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[PATCH v2 00/21] arm64: Virtualization Host Extension support

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  [PATCH v2 00/21] arm64: Virtualization Host Extension support Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:00 +0100
    [PATCH v2 16/21] arm64: KVM: VHE: Add fpsimd enabling on guest access Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:00 +0100
    [PATCH v2 09/21] arm64: KVM: VHE: Differenciate host/guest sysreg save/restore Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:00 +0100
    [PATCH v2 06/21] arm64: KVM: VHE: Patch out use of HVC Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:00 +0100
    [PATCH v2 15/21] arm64: KVM: VHE: Use unified sysreg accessors for timer Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:00 +0100
    [PATCH v2 21/21] arm64: Panic when VHE and non VHE CPUs coexist Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:00 +0100
      Re: [PATCH v2 21/21] arm64: Panic when VHE and non VHE CPUs coexist "Suzuki K. Poulose" <Suzuki.Poulose@arm.com> - 2016-01-26 15:30 +0100
        Re: [PATCH v2 21/21] arm64: Panic when VHE and non VHE CPUs coexist Marc Zyngier <marc.zyngier@arm.com> - 2016-01-26 15:40 +0100
    [PATCH v2 10/21] arm64: KVM: VHE: Split save/restore of sysregs shared between EL1 and EL2 Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:00 +0100
    [PATCH v2 20/21] arm64: VHE: Add support for running Linux in EL2 mode Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:00 +0100
      Re: [PATCH v2 20/21] arm64: VHE: Add support for running Linux in EL2  mode "Suzuki K. Poulose" <Suzuki.Poulose@arm.com> - 2016-01-26 15:10 +0100
        Re: [PATCH v2 20/21] arm64: VHE: Add support for running Linux in EL2  mode "Suzuki K. Poulose" <Suzuki.Poulose@arm.com> - 2016-01-26 15:40 +0100
    [PATCH v2 17/21] arm64: KVM: VHE: Add alternative panic handling Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:00 +0100
    [PATCH v2 05/21] arm64: KVM: VHE: Turn VTCR_EL2 setup into a reusable macro Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:00 +0100
    [PATCH v2 11/21] arm64: KVM: VHE: Use unified system register accessors Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:10 +0100
    [PATCH v2 03/21] arm64: Add ARM64_HAS_VIRT_HOST_EXTN feature Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:10 +0100
    [PATCH v2 08/21] arm64: KVM: VHE: Introduce unified system register accessors Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:10 +0100
    [PATCH v2 04/21] arm64: KVM: Skip HYP setup when already running in HYP Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:10 +0100
    [PATCH v2 02/21] arm64: Allow the arch timer to use the HYP timer Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:10 +0100
    [PATCH v2 13/21] arm64: KVM: VHE: Make __fpsimd_enabled VHE aware Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:10 +0100
    [PATCH v2 14/21] arm64: KVM: VHE: Implement VHE activate/deactivate_traps Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:10 +0100
    [PATCH v2 07/21] arm64: KVM: VHE: Patch out kern_hyp_va Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:10 +0100
    Re: [PATCH v2 00/21] arm64: Virtualization Host Extension support Arnd Bergmann <arnd@arndb.de> - 2016-01-25 17:20 +0100
      Re: [PATCH v2 00/21] arm64: Virtualization Host Extension support Arnd Bergmann <arnd@arndb.de> - 2016-01-25 17:30 +0100
      Re: [PATCH v2 00/21] arm64: Virtualization Host Extension support Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:30 +0100
    Re: [PATCH v2 00/21] arm64: Virtualization Host Extension support Will Deacon <will.deacon@arm.com> - 2016-01-25 17:30 +0100
      Re: [PATCH v2 00/21] arm64: Virtualization Host Extension support Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 17:40 +0100
        Re: [PATCH v2 00/21] arm64: Virtualization Host Extension support Will Deacon <will.deacon@arm.com> - 2016-01-25 17:50 +0100
          Re: [PATCH v2 00/21] arm64: Virtualization Host Extension support Marc Zyngier <marc.zyngier@arm.com> - 2016-01-25 20:20 +0100

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#1316892 — [PATCH v2 00/21] arm64: Virtualization Host Extension support

ARMv8.1 comes with the "Virtualization Host Extension" (VHE for
short), which enables simpler support of Type-2 hypervisors.

This extension allows the kernel to directly run at EL2, and
significantly reduces the number of system registers shared between
host and guest, reducing the overhead of virtualization.

In order to have the same kernel binary running on all versions of the
architecture, this series makes heavy use of runtime code patching.

The first 20 patches massage the KVM code to deal with VHE and enable
Linux to run at EL2. The last patch catches an ugly case when VHE
capable CPUs are paired with some of their less capable siblings. This
should never happen, but hey...

I have deliberately left out some of the more "advanced"
optimizations, as they are likely to distract the reviewer from the
core infrastructure, which is what I care about at the moment.

A few things to note:

- Given that the code has been almost entierely rewritten, I've
  dropped all Acks from the new patches

- GDB is currently busted on VHE systems, as it checks for version 6
  on the debug architecture, while VHE is version 7. The binutils
  people are on the case.

This has been tested on the FVP_Base_SLV-V8-A model, and based on
v4.5-rc1. I've put a branch out on:

git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git kvm-arm64/vhe

* From v1:
  - Full rewrite now that the World Switch is written in C code.
  - Dropped the "early IRQ handling" for the moment.

Marc Zyngier (21):
  arm/arm64: Add new is_kernel_in_hyp_mode predicate
  arm64: Allow the arch timer to use the HYP timer
  arm64: Add ARM64_HAS_VIRT_HOST_EXTN feature
  arm64: KVM: Skip HYP setup when already running in HYP
  arm64: KVM: VHE: Turn VTCR_EL2 setup into a reusable macro
  arm64: KVM: VHE: Patch out use of HVC
  arm64: KVM: VHE: Patch out kern_hyp_va
  arm64: KVM: VHE: Introduce unified system register accessors
  arm64: KVM: VHE: Differenciate host/guest sysreg save/restore
  arm64: KVM: VHE: Split save/restore of sysregs shared between EL1 and
    EL2
  arm64: KVM: VHE: Use unified system register accessors
  arm64: KVM: VHE: Enable minimal sysreg save/restore
  arm64: KVM: VHE: Make __fpsimd_enabled VHE aware
  arm64: KVM: VHE: Implement VHE activate/deactivate_traps
  arm64: KVM: VHE: Use unified sysreg accessors for timer
  arm64: KVM: VHE: Add fpsimd enabling on guest access
  arm64: KVM: VHE: Add alternative panic handling
  arm64: KVM: Introduce hyp_alternate_value helper
  arm64: KVM: Move most of the fault decoding to C
  arm64: VHE: Add support for running Linux in EL2 mode
  arm64: Panic when VHE and non VHE CPUs coexist

 arch/arm/include/asm/virt.h          |   5 ++
 arch/arm/kvm/arm.c                   | 151 +++++++++++++++++++------------
 arch/arm/kvm/mmu.c                   |   7 ++
 arch/arm64/Kconfig                   |  13 +++
 arch/arm64/include/asm/cpufeature.h  |   3 +-
 arch/arm64/include/asm/kvm_arm.h     |   1 +
 arch/arm64/include/asm/kvm_emulate.h |   3 +
 arch/arm64/include/asm/kvm_mmu.h     |  34 ++++++-
 arch/arm64/include/asm/virt.h        |  27 ++++++
 arch/arm64/kernel/asm-offsets.c      |   3 -
 arch/arm64/kernel/cpufeature.c       |  15 +++-
 arch/arm64/kernel/head.S             |  51 ++++++++++-
 arch/arm64/kernel/smp.c              |   3 +
 arch/arm64/kvm/hyp-init.S            |  18 +---
 arch/arm64/kvm/hyp.S                 |   7 ++
 arch/arm64/kvm/hyp/entry.S           |   6 ++
 arch/arm64/kvm/hyp/hyp-entry.S       | 107 +++++++---------------
 arch/arm64/kvm/hyp/hyp.h             | 119 ++++++++++++++++++++++--
 arch/arm64/kvm/hyp/switch.c          | 170 +++++++++++++++++++++++++++++++----
 arch/arm64/kvm/hyp/sysreg-sr.c       | 147 ++++++++++++++++++++----------
 arch/arm64/kvm/hyp/timer-sr.c        |  10 +--
 drivers/clocksource/arm_arch_timer.c |  96 ++++++++++++--------
 22 files changed, 724 insertions(+), 272 deletions(-)

-- 
2.1.4

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#1316893 — [PATCH v2 16/21] arm64: KVM: VHE: Add fpsimd enabling on guest access

Despite the fact that a VHE enabled kernel runs at EL2, it uses
CPACR_EL1 to trap FPSIMD access. Add the required alternative
code to re-enable guest FPSIMD access when it has trapped to
EL2.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp/entry.S | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index fd0fbe9..759a0ec 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -130,9 +130,15 @@ ENDPROC(__guest_exit)
 ENTRY(__fpsimd_guest_restore)
 	stp	x4, lr, [sp, #-16]!
 
+alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
 	mrs	x2, cptr_el2
 	bic	x2, x2, #CPTR_EL2_TFP
 	msr	cptr_el2, x2
+alternative_else
+	mrs	x2, cpacr_el1
+	orr	x2, x2, #(3 << 20)
+	msr	cpacr_el1, x2
+alternative_endif
 	isb
 
 	mrs	x3, tpidr_el2
-- 
2.1.4

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#1316894 — [PATCH v2 09/21] arm64: KVM: VHE: Differenciate host/guest sysreg save/restore

With ARMv8, host and guest share the same system register file,
making the save/restore procedure completely symetrical.
With VHE, host and guest now have different requirements, as they
use different sysregs.

In order to prepare for this, add split sysreg save/restore functions
for both host and guest. No functionnal change yet.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp/hyp.h       |  6 ++++--
 arch/arm64/kvm/hyp/switch.c    | 10 +++++-----
 arch/arm64/kvm/hyp/sysreg-sr.c | 24 ++++++++++++++++++++++--
 3 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
index 744c919..5dfa883 100644
--- a/arch/arm64/kvm/hyp/hyp.h
+++ b/arch/arm64/kvm/hyp/hyp.h
@@ -153,8 +153,10 @@ void __vgic_v3_restore_state(struct kvm_vcpu *vcpu);
 void __timer_save_state(struct kvm_vcpu *vcpu);
 void __timer_restore_state(struct kvm_vcpu *vcpu);
 
-void __sysreg_save_state(struct kvm_cpu_context *ctxt);
-void __sysreg_restore_state(struct kvm_cpu_context *ctxt);
+void __sysreg_save_host_state(struct kvm_cpu_context *ctxt);
+void __sysreg_restore_host_state(struct kvm_cpu_context *ctxt);
+void __sysreg_save_guest_state(struct kvm_cpu_context *ctxt);
+void __sysreg_restore_guest_state(struct kvm_cpu_context *ctxt);
 void __sysreg32_save_state(struct kvm_vcpu *vcpu);
 void __sysreg32_restore_state(struct kvm_vcpu *vcpu);
 
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index ca8f5a5..9071dee 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -98,7 +98,7 @@ static int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
 	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
 	guest_ctxt = &vcpu->arch.ctxt;
 
-	__sysreg_save_state(host_ctxt);
+	__sysreg_save_host_state(host_ctxt);
 	__debug_cond_save_host_state(vcpu);
 
 	__activate_traps(vcpu);
@@ -112,7 +112,7 @@ static int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
 	 * to Cortex-A57 erratum #852523.
 	 */
 	__sysreg32_restore_state(vcpu);
-	__sysreg_restore_state(guest_ctxt);
+	__sysreg_restore_guest_state(guest_ctxt);
 	__debug_restore_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt);
 
 	/* Jump in the fire! */
@@ -121,7 +121,7 @@ static int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
 
 	fp_enabled = __fpsimd_enabled();
 
-	__sysreg_save_state(guest_ctxt);
+	__sysreg_save_guest_state(guest_ctxt);
 	__sysreg32_save_state(vcpu);
 	__timer_save_state(vcpu);
 	__vgic_save_state(vcpu);
@@ -129,7 +129,7 @@ static int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
 	__deactivate_traps(vcpu);
 	__deactivate_vm(vcpu);
 
-	__sysreg_restore_state(host_ctxt);
+	__sysreg_restore_host_state(host_ctxt);
 
 	if (fp_enabled) {
 		__fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
@@ -161,7 +161,7 @@ void __hyp_text __noreturn __hyp_panic(void)
 		host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
 		__deactivate_traps(vcpu);
 		__deactivate_vm(vcpu);
-		__sysreg_restore_state(host_ctxt);
+		__sysreg_restore_host_state(host_ctxt);
 	}
 
 	/* Call panic for real */
diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index 42563098..bd5b543 100644
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -24,7 +24,7 @@
 #include "hyp.h"
 
 /* ctxt is already in the HYP VA space */
-void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
+static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
 {
 	ctxt->sys_regs[MPIDR_EL1]	= read_sysreg(vmpidr_el2);
 	ctxt->sys_regs[CSSELR_EL1]	= read_sysreg(csselr_el1);
@@ -57,7 +57,17 @@ void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
 	ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg(spsr_el1);
 }
 
-void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
+void __hyp_text __sysreg_save_host_state(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_save_state(ctxt);
+}
+
+void __hyp_text __sysreg_save_guest_state(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_save_state(ctxt);
+}
+
+static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
 {
 	write_sysreg(ctxt->sys_regs[MPIDR_EL1],	  vmpidr_el2);
 	write_sysreg(ctxt->sys_regs[CSSELR_EL1],  csselr_el1);
@@ -90,6 +100,16 @@ void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
 	write_sysreg(ctxt->gp_regs.spsr[KVM_SPSR_EL1], spsr_el1);
 }
 
+void __hyp_text __sysreg_restore_host_state(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_restore_state(ctxt);
+}
+
+void __hyp_text __sysreg_restore_guest_state(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_restore_state(ctxt);
+}
+
 void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
 {
 	u64 *spsr, *sysreg;
-- 
2.1.4

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#1316895 — [PATCH v2 06/21] arm64: KVM: VHE: Patch out use of HVC

With VHE, the host never issues an HVC instruction to get into the
KVM code, as we can simply branch there.

Use runtime code patching to simplify things a bit.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp.S           |  7 +++++++
 arch/arm64/kvm/hyp/hyp-entry.S | 38 +++++++++++++++++++++++++++++---------
 2 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 0ccdcbb..0689a74 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -17,7 +17,9 @@
 
 #include <linux/linkage.h>
 
+#include <asm/alternative.h>
 #include <asm/assembler.h>
+#include <asm/cpufeature.h>
 
 /*
  * u64 kvm_call_hyp(void *hypfn, ...);
@@ -38,6 +40,11 @@
  * arch/arm64/kernel/hyp_stub.S.
  */
 ENTRY(kvm_call_hyp)
+alternative_if_not ARM64_HAS_VIRT_HOST_EXTN	
 	hvc	#0
 	ret
+alternative_else
+	b	__vhe_hyp_call
+	nop
+alternative_endif
 ENDPROC(kvm_call_hyp)
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 93e8d983..9e0683f 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -38,6 +38,32 @@
 	ldp	x0, x1, [sp], #16
 .endm
 
+.macro do_el2_call
+	/*
+	 * Shuffle the parameters before calling the function
+	 * pointed to in x0. Assumes parameters in x[1,2,3].
+	 */
+	stp	lr, xzr, [sp, #-16]!
+	mov	lr, x0
+	mov	x0, x1
+	mov	x1, x2
+	mov	x2, x3
+	blr	lr
+	ldp	lr, xzr, [sp], #16
+.endm
+
+ENTRY(__vhe_hyp_call)
+	do_el2_call
+	/*
+	 * We used to rely on having an exception return to get
+	 * an implicit isb. In the E2H case, we don't have it anymore.
+	 * rather than changing all the leaf functions, just do it here
+	 * before returning to the rest of the kernel.
+	 */
+	isb
+	ret
+ENDPROC(__vhe_hyp_call)
+	
 el1_sync:				// Guest trapped into EL2
 	save_x0_to_x3
 
@@ -58,19 +84,13 @@ el1_sync:				// Guest trapped into EL2
 	mrs	x0, vbar_el2
 	b	2f
 
-1:	stp	lr, xzr, [sp, #-16]!
-
+1:
 	/*
-	 * Compute the function address in EL2, and shuffle the parameters.
+	 * Perform the EL2 call
 	 */
 	kern_hyp_va	x0
-	mov	lr, x0
-	mov	x0, x1
-	mov	x1, x2
-	mov	x2, x3
-	blr	lr
+	do_el2_call
 
-	ldp	lr, xzr, [sp], #16
 2:	eret
 
 el1_trap:
-- 
2.1.4

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#1316900 — [PATCH v2 15/21] arm64: KVM: VHE: Use unified sysreg accessors for timer

Switch the timer code to the unified sysreg accessors.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp/timer-sr.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/hyp/timer-sr.c b/arch/arm64/kvm/hyp/timer-sr.c
index 1051e5d..f276d9e 100644
--- a/arch/arm64/kvm/hyp/timer-sr.c
+++ b/arch/arm64/kvm/hyp/timer-sr.c
@@ -31,12 +31,12 @@ void __hyp_text __timer_save_state(struct kvm_vcpu *vcpu)
 	u64 val;
 
 	if (kvm->arch.timer.enabled) {
-		timer->cntv_ctl = read_sysreg(cntv_ctl_el0);
-		timer->cntv_cval = read_sysreg(cntv_cval_el0);
+		timer->cntv_ctl = read_sysreg_el0(cntv_ctl);
+		timer->cntv_cval = read_sysreg_el0(cntv_cval);
 	}
 
 	/* Disable the virtual timer */
-	write_sysreg(0, cntv_ctl_el0);
+	write_sysreg_el0(0, cntv_ctl);
 
 	/* Allow physical timer/counter access for the host */
 	val = read_sysreg(cnthctl_el2);
@@ -64,8 +64,8 @@ void __hyp_text __timer_restore_state(struct kvm_vcpu *vcpu)
 
 	if (kvm->arch.timer.enabled) {
 		write_sysreg(kvm->arch.timer.cntvoff, cntvoff_el2);
-		write_sysreg(timer->cntv_cval, cntv_cval_el0);
+		write_sysreg_el0(timer->cntv_cval, cntv_cval);
 		isb();
-		write_sysreg(timer->cntv_ctl, cntv_ctl_el0);
+		write_sysreg_el0(timer->cntv_ctl, cntv_ctl);
 	}
 }
-- 
2.1.4

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#1316903 — [PATCH v2 21/21] arm64: Panic when VHE and non VHE CPUs coexist

Having both VHE and non-VHE capable CPUs in the same system
is likely to be a recipe for disaster.

If the boot CPU has VHE, but a secondary is not, we won't be
able to downgrade and run the kernel at EL1. Add CPU hotplug
to the mix, and this produces a terrifying mess.

Let's solve the problem once and for all. If you mix VHE and
non-VHE CPUs in the same system, you deserve to loose, and this
patch makes sure you don't get a chance.

This is implemented by storing the kernel execution level in
a global variable. Secondaries will park themselves in a
WFI loop if they observe a mismatch. Also, the primary CPU
will detect that the secondary CPU has died on a mismatched
execution level. Panic will follow.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/virt.h | 17 +++++++++++++++++
 arch/arm64/kernel/head.S      | 19 +++++++++++++++++++
 arch/arm64/kernel/smp.c       |  3 +++
 3 files changed, 39 insertions(+)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 9f22dd6..f81a345 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -36,6 +36,11 @@
  */
 extern u32 __boot_cpu_mode[2];
 
+/*
+ * __run_cpu_mode records the mode the boot CPU uses for the kernel.
+ */
+extern u32 __run_cpu_mode[2];
+
 void __hyp_set_vectors(phys_addr_t phys_vector_base);
 phys_addr_t __hyp_get_vectors(void);
 
@@ -60,6 +65,18 @@ static inline bool is_kernel_in_hyp_mode(void)
 	return el == CurrentEL_EL2;
 }
 
+static inline bool is_kernel_mode_mismatched(void)
+{
+	/*
+	 * A mismatched CPU will have written its own CurrentEL in
+	 * __run_cpu_mode[1] (initially set to zero) after failing to
+	 * match the value in __run_cpu_mode[0]. Thus, a non-zero
+	 * value in __run_cpu_mode[1] is enough to detect the
+	 * pathological case.
+	 */
+	return !!ACCESS_ONCE(__run_cpu_mode[1]);
+}
+
 /* The section containing the hypervisor text */
 extern char __hyp_text_start[];
 extern char __hyp_text_end[];
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 2a7134c..bc44cf8 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -577,7 +577,23 @@ ENTRY(set_cpu_boot_mode_flag)
 1:	str	w20, [x1]			// This CPU has booted in EL1
 	dmb	sy
 	dc	ivac, x1			// Invalidate potentially stale cache line
+	adr_l	x1, __run_cpu_mode
+	ldr	w0, [x1]
+	mrs	x20, CurrentEL
+	cbz	x0, skip_el_check
+	cmp	x0, x20
+	bne	mismatched_el
+skip_el_check:			// Only the first CPU gets to set the rule
+	str	w20, [x1]
+	dmb	sy
+	dc	ivac, x1	// Invalidate potentially stale cache line
 	ret
+mismatched_el:
+	str	w20, [x1, #4]
+	dmb	sy
+	dc	ivac, x1	// Invalidate potentially stale cache line
+1:	wfi
+	b	1b
 ENDPROC(set_cpu_boot_mode_flag)
 
 /*
@@ -592,6 +608,9 @@ ENDPROC(set_cpu_boot_mode_flag)
 ENTRY(__boot_cpu_mode)
 	.long	BOOT_CPU_MODE_EL2
 	.long	BOOT_CPU_MODE_EL1
+ENTRY(__run_cpu_mode)
+	.long	0
+	.long	0
 	.popsection
 
 	/*
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index b1adc51..bc7650a 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -113,6 +113,9 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
 			pr_crit("CPU%u: failed to come online\n", cpu);
 			ret = -EIO;
 		}
+
+		if (is_kernel_mode_mismatched())
+			panic("CPU%u: incompatible execution level", cpu);
 	} else {
 		pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
 	}
-- 
2.1.4

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#1317963 — Re: [PATCH v2 21/21] arm64: Panic when VHE and non VHE CPUs coexist

On 25/01/16 15:53, Marc Zyngier wrote:
> Having both VHE and non-VHE capable CPUs in the same system
> is likely to be a recipe for disaster.


> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index b1adc51..bc7650a 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -113,6 +113,9 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
>   			pr_crit("CPU%u: failed to come online\n", cpu);
>   			ret = -EIO;
>   		}
> +
> +		if (is_kernel_mode_mismatched())
> +			panic("CPU%u: incompatible execution level", cpu);


fyi,

I have a series which tries to perform some checks for early CPU features,
like this at [1] and adds support for early CPU boot failures, passing the error
status back to the master. May be we could move this check there(once it settles),
and fail the CPU boot with CPU_PANIC_KERNEL status.


[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-January/401727.html

Thanks
Suzuki

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#1317981 — Re: [PATCH v2 21/21] arm64: Panic when VHE and non VHE CPUs coexist

On 26/01/16 14:25, Suzuki K. Poulose wrote:
> On 25/01/16 15:53, Marc Zyngier wrote:
>> Having both VHE and non-VHE capable CPUs in the same system
>> is likely to be a recipe for disaster.
> 
> 
>> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
>> index b1adc51..bc7650a 100644
>> --- a/arch/arm64/kernel/smp.c
>> +++ b/arch/arm64/kernel/smp.c
>> @@ -113,6 +113,9 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
>>   			pr_crit("CPU%u: failed to come online\n", cpu);
>>   			ret = -EIO;
>>   		}
>> +
>> +		if (is_kernel_mode_mismatched())
>> +			panic("CPU%u: incompatible execution level", cpu);
> 
> 
> fyi,
> 
> I have a series which tries to perform some checks for early CPU features,
> like this at [1] and adds support for early CPU boot failures, passing the error
> status back to the master. May be we could move this check there(once it settles),
> and fail the CPU boot with CPU_PANIC_KERNEL status.
> 
> 
> [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-January/401727.html

Definitely, there is room for consolidation in this area...

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

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#1316904 — [PATCH v2 10/21] arm64: KVM: VHE: Split save/restore of sysregs shared between EL1 and EL2

A handful of system registers are still shared between EL1 and EL2,
even while using VHE. These are tpidr*_el[01], actlr_el1, sp0, elr,
and spsr.

In order to facilitate the introduction of a VHE-specific sysreg
save/restore, make move the access to these registers to their
own save/restore functions.

No functionnal change.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp/sysreg-sr.c | 48 +++++++++++++++++++++++++++++-------------
 1 file changed, 33 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index bd5b543..61bad17 100644
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -23,13 +23,29 @@
 
 #include "hyp.h"
 
-/* ctxt is already in the HYP VA space */
+/*
+ * Non-VHE: Both host and guest must save everything.
+ *
+ * VHE: Host must save tpidr*_el[01], actlr_el1, sp0, pc, pstate, and
+ * guest must save everything.
+ */
+
+static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
+{
+	ctxt->sys_regs[ACTLR_EL1]	= read_sysreg(actlr_el1);
+	ctxt->sys_regs[TPIDR_EL0]	= read_sysreg(tpidr_el0);
+	ctxt->sys_regs[TPIDRRO_EL0]	= read_sysreg(tpidrro_el0);
+	ctxt->sys_regs[TPIDR_EL1]	= read_sysreg(tpidr_el1);
+	ctxt->gp_regs.regs.sp		= read_sysreg(sp_el0);
+	ctxt->gp_regs.regs.pc		= read_sysreg(elr_el2);
+	ctxt->gp_regs.regs.pstate	= read_sysreg(spsr_el2);
+}
+
 static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
 {
 	ctxt->sys_regs[MPIDR_EL1]	= read_sysreg(vmpidr_el2);
 	ctxt->sys_regs[CSSELR_EL1]	= read_sysreg(csselr_el1);
 	ctxt->sys_regs[SCTLR_EL1]	= read_sysreg(sctlr_el1);
-	ctxt->sys_regs[ACTLR_EL1]	= read_sysreg(actlr_el1);
 	ctxt->sys_regs[CPACR_EL1]	= read_sysreg(cpacr_el1);
 	ctxt->sys_regs[TTBR0_EL1]	= read_sysreg(ttbr0_el1);
 	ctxt->sys_regs[TTBR1_EL1]	= read_sysreg(ttbr1_el1);
@@ -41,17 +57,11 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
 	ctxt->sys_regs[MAIR_EL1]	= read_sysreg(mair_el1);
 	ctxt->sys_regs[VBAR_EL1]	= read_sysreg(vbar_el1);
 	ctxt->sys_regs[CONTEXTIDR_EL1]	= read_sysreg(contextidr_el1);
-	ctxt->sys_regs[TPIDR_EL0]	= read_sysreg(tpidr_el0);
-	ctxt->sys_regs[TPIDRRO_EL0]	= read_sysreg(tpidrro_el0);
-	ctxt->sys_regs[TPIDR_EL1]	= read_sysreg(tpidr_el1);
 	ctxt->sys_regs[AMAIR_EL1]	= read_sysreg(amair_el1);
 	ctxt->sys_regs[CNTKCTL_EL1]	= read_sysreg(cntkctl_el1);
 	ctxt->sys_regs[PAR_EL1]		= read_sysreg(par_el1);
 	ctxt->sys_regs[MDSCR_EL1]	= read_sysreg(mdscr_el1);
 
-	ctxt->gp_regs.regs.sp		= read_sysreg(sp_el0);
-	ctxt->gp_regs.regs.pc		= read_sysreg(elr_el2);
-	ctxt->gp_regs.regs.pstate	= read_sysreg(spsr_el2);
 	ctxt->gp_regs.sp_el1		= read_sysreg(sp_el1);
 	ctxt->gp_regs.elr_el1		= read_sysreg(elr_el1);
 	ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg(spsr_el1);
@@ -60,11 +70,24 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
 void __hyp_text __sysreg_save_host_state(struct kvm_cpu_context *ctxt)
 {
 	__sysreg_save_state(ctxt);
+	__sysreg_save_common_state(ctxt);
 }
 
 void __hyp_text __sysreg_save_guest_state(struct kvm_cpu_context *ctxt)
 {
 	__sysreg_save_state(ctxt);
+	__sysreg_save_common_state(ctxt);
+}
+
+static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
+{
+	write_sysreg(ctxt->sys_regs[ACTLR_EL1],	  actlr_el1);
+	write_sysreg(ctxt->sys_regs[TPIDR_EL0],	  tpidr_el0);
+	write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
+	write_sysreg(ctxt->sys_regs[TPIDR_EL1],	  tpidr_el1);
+	write_sysreg(ctxt->gp_regs.regs.sp,	  sp_el0);
+	write_sysreg(ctxt->gp_regs.regs.pc,	  elr_el2);
+	write_sysreg(ctxt->gp_regs.regs.pstate,	  spsr_el2);
 }
 
 static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
@@ -72,7 +95,6 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
 	write_sysreg(ctxt->sys_regs[MPIDR_EL1],	  vmpidr_el2);
 	write_sysreg(ctxt->sys_regs[CSSELR_EL1],  csselr_el1);
 	write_sysreg(ctxt->sys_regs[SCTLR_EL1],	  sctlr_el1);
-	write_sysreg(ctxt->sys_regs[ACTLR_EL1],	  actlr_el1);
 	write_sysreg(ctxt->sys_regs[CPACR_EL1],	  cpacr_el1);
 	write_sysreg(ctxt->sys_regs[TTBR0_EL1],	  ttbr0_el1);
 	write_sysreg(ctxt->sys_regs[TTBR1_EL1],	  ttbr1_el1);
@@ -84,17 +106,11 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
 	write_sysreg(ctxt->sys_regs[MAIR_EL1],	  mair_el1);
 	write_sysreg(ctxt->sys_regs[VBAR_EL1],	  vbar_el1);
 	write_sysreg(ctxt->sys_regs[CONTEXTIDR_EL1], contextidr_el1);
-	write_sysreg(ctxt->sys_regs[TPIDR_EL0],	  tpidr_el0);
-	write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
-	write_sysreg(ctxt->sys_regs[TPIDR_EL1],	  tpidr_el1);
 	write_sysreg(ctxt->sys_regs[AMAIR_EL1],	  amair_el1);
 	write_sysreg(ctxt->sys_regs[CNTKCTL_EL1], cntkctl_el1);
 	write_sysreg(ctxt->sys_regs[PAR_EL1],	  par_el1);
 	write_sysreg(ctxt->sys_regs[MDSCR_EL1],	  mdscr_el1);
 
-	write_sysreg(ctxt->gp_regs.regs.sp,	sp_el0);
-	write_sysreg(ctxt->gp_regs.regs.pc,	elr_el2);
-	write_sysreg(ctxt->gp_regs.regs.pstate,	spsr_el2);
 	write_sysreg(ctxt->gp_regs.sp_el1,	sp_el1);
 	write_sysreg(ctxt->gp_regs.elr_el1,	elr_el1);
 	write_sysreg(ctxt->gp_regs.spsr[KVM_SPSR_EL1], spsr_el1);
@@ -103,11 +119,13 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
 void __hyp_text __sysreg_restore_host_state(struct kvm_cpu_context *ctxt)
 {
 	__sysreg_restore_state(ctxt);
+	__sysreg_restore_common_state(ctxt);
 }
 
 void __hyp_text __sysreg_restore_guest_state(struct kvm_cpu_context *ctxt)
 {
 	__sysreg_restore_state(ctxt);
+	__sysreg_restore_common_state(ctxt);
 }
 
 void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
-- 
2.1.4

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#1316905 — [PATCH v2 20/21] arm64: VHE: Add support for running Linux in EL2 mode

With ARMv8.1 VHE, the architecture is able to (almost) transparently
run the kernel at EL2, despite being written for EL1.

This patch takes care of the "almost" part, mostly preventing the kernel
from dropping from EL2 to EL1, and setting up the HYP configuration.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/Kconfig       | 13 +++++++++++++
 arch/arm64/kernel/head.S | 32 +++++++++++++++++++++++++++++++-
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 8cc6228..ada34df 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -750,6 +750,19 @@ config ARM64_LSE_ATOMICS
 	  not support these instructions and requires the kernel to be
 	  built with binutils >= 2.25.
 
+config ARM64_VHE
+	bool "Enable support for Virtualization Host Extension (VHE)"
+	default y
+	help
+	  Virtualization Host Extension (VHE) allows the kernel to run
+	  directly at EL2 (instead of EL1) on processors that support
+	  it. This leads to better performance for KVM, as it reduces
+	  the cost of the world switch.
+
+	  Selecting this option allows the VHE feature to be detected
+	  at runtime, and does not affect processors that do not
+	  implement this feature.
+
 endmenu
 
 endmenu
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index ffe9c2b..2a7134c 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -30,6 +30,7 @@
 #include <asm/cache.h>
 #include <asm/cputype.h>
 #include <asm/kernel-pgtable.h>
+#include <asm/kvm_mmu.h>
 #include <asm/memory.h>
 #include <asm/pgtable-hwdef.h>
 #include <asm/pgtable.h>
@@ -464,8 +465,25 @@ CPU_LE(	bic	x0, x0, #(3 << 24)	)	// Clear the EE and E0E bits for EL1
 	isb
 	ret
 
+2:
+#ifdef CONFIG_ARM64_VHE
+	/*
+	 * Check for VHE being present. For the rest of the EL2 setup,
+	 * x2 being non-zero indicates that we do have VHE, and that the
+	 * kernel is intended to run at EL2.
+	 */
+	mrs	x2, id_aa64mmfr1_el1
+	ubfx	x2, x2, #8, #4
+#else
+	mov	x2, xzr
+#endif
+
 	/* Hyp configuration. */
-2:	mov	x0, #(1 << 31)			// 64-bit EL1
+	mov	x0, #HCR_RW			// 64-bit EL1
+	cbz	x2, set_hcr
+	orr	x0, x0, #HCR_TGE		// Enable Host Extensions
+	orr	x0, x0, #HCR_E2H
+set_hcr:
 	msr	hcr_el2, x0
 
 	/* Generic timers. */
@@ -507,6 +525,9 @@ CPU_LE(	movk	x0, #0x30d0, lsl #16	)	// Clear EE and E0E on LE systems
 
 	/* Coprocessor traps. */
 	mov	x0, #0x33ff
+	cbz	x2, set_cptr
+	orr	x0, x0, #(3 << 20)		// Don't trap FP
+set_cptr:
 	msr	cptr_el2, x0			// Disable copro. traps to EL2
 
 #ifdef CONFIG_COMPAT
@@ -521,6 +542,15 @@ CPU_LE(	movk	x0, #0x30d0, lsl #16	)	// Clear EE and E0E on LE systems
 	/* Stage-2 translation */
 	msr	vttbr_el2, xzr
 
+	cbz	x2, install_el2_stub
+
+	setup_vtcr x4, x5
+
+	mov	w20, #BOOT_CPU_MODE_EL2		// This CPU booted in EL2
+	isb
+	ret
+
+install_el2_stub:
 	/* Hypervisor stub */
 	adrp	x0, __hyp_stub_vectors
 	add	x0, x0, #:lo12:__hyp_stub_vectors
-- 
2.1.4

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#1317942 — Re: [PATCH v2 20/21] arm64: VHE: Add support for running Linux in EL2 mode

On 25/01/16 15:53, Marc Zyngier wrote:
> With ARMv8.1 VHE, the architecture is able to (almost) transparently
> run the kernel at EL2, despite being written for EL1.
>
> This patch takes care of the "almost" part, mostly preventing the kernel
> from dropping from EL2 to EL1, and setting up the HYP configuration.

>   #ifdef CONFIG_COMPAT
> @@ -521,6 +542,15 @@ CPU_LE(	movk	x0, #0x30d0, lsl #16	)	// Clear EE and E0E on LE systems
>   	/* Stage-2 translation */
>   	msr	vttbr_el2, xzr
>
> +	cbz	x2, install_el2_stub

Though it is apparent, may be its worth adding a comment here that we don't drop to EL1 here ?

> +
> +	setup_vtcr x4, x5
> +
> +	mov	w20, #BOOT_CPU_MODE_EL2		// This CPU booted in EL2
> +	isb
> +	ret

> +
> +install_el2_stub:

And a comment here mentioning, install the hyp stub and drops to EL1 ?

>   	/* Hypervisor stub */
>   	adrp	x0, __hyp_stub_vectors
>   	add	x0, x0, #:lo12:__hyp_stub_vectors
>

Cheers
Suzuki

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#1317985 — Re: [PATCH v2 20/21] arm64: VHE: Add support for running Linux in EL2 mode

On 26/01/16 14:04, Suzuki K. Poulose wrote:
> On 25/01/16 15:53, Marc Zyngier wrote:
>> With ARMv8.1 VHE, the architecture is able to (almost) transparently
>> run the kernel at EL2, despite being written for EL1.
>>
>> This patch takes care of the "almost" part, mostly preventing the kernel
>> from dropping from EL2 to EL1, and setting up the HYP configuration.
>
>>   #ifdef CONFIG_COMPAT
>> @@ -521,6 +542,15 @@ CPU_LE(    movk    x0, #0x30d0, lsl #16    )    // Clear EE and E0E on LE systems
>>       /* Stage-2 translation */
>>       msr    vttbr_el2, xzr
>>
>> +    cbz    x2, install_el2_stub
>
> Though it is apparent, may be its worth adding a comment here that we don't drop to EL1 here ?
>
>> +
>> +    setup_vtcr x4, x5
>> +
>> +    mov    w20, #BOOT_CPU_MODE_EL2        // This CPU booted in EL2
>> +    isb
>> +    ret
>
>> +
>> +install_el2_stub:
>
> And a comment here mentioning, install the hyp stub and drops to EL1 ?

Also, the comments around el2_setup invocation still says, Drop to EL1 which may
need to be updated.

Cheers
Suzuki

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#1316906 — [PATCH v2 17/21] arm64: KVM: VHE: Add alternative panic handling

As the kernel fully runs in HYP when VHE is enabled, we can
directly branch to the kernel's panic() implementation, and
not perform an exception return.

Add the alternative code to deal with this.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp/switch.c | 35 +++++++++++++++++++++++++++--------
 1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 77f7c94..0cadb7f 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -211,11 +211,34 @@ __alias(__guest_run) int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
 
 static const char __hyp_panic_string[] = "HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n";
 
-void __hyp_text __noreturn __hyp_panic(void)
+static void __hyp_text __hyp_call_panic_nvhe(u64 spsr, u64 elr, u64 par)
 {
 	unsigned long str_va = (unsigned long)__hyp_panic_string;
-	u64 spsr = read_sysreg(spsr_el2);
-	u64 elr = read_sysreg(elr_el2);
+
+	__hyp_do_panic(hyp_kern_va(str_va),
+		       spsr,  elr,
+		       read_sysreg(esr_el2),   read_sysreg_el2(far),
+		       read_sysreg(hpfar_el2), par,
+		       (void *)read_sysreg(tpidr_el2));
+}
+
+static void __hyp_text __hyp_call_panic_vhe(u64 spsr, u64 elr, u64 par)
+{
+	panic(__hyp_panic_string,
+	      spsr,  elr,
+	      read_sysreg_el2(esr),   read_sysreg_el2(far),
+	      read_sysreg(hpfar_el2), par,
+	      (void *)read_sysreg(tpidr_el2));
+}
+
+static hyp_alternate_select(__hyp_call_panic,
+			    __hyp_call_panic_nvhe, __hyp_call_panic_vhe,
+			    ARM64_HAS_VIRT_HOST_EXTN);
+
+void __hyp_text __noreturn __hyp_panic(void)
+{
+	u64 spsr = read_sysreg_el2(spsr);
+	u64 elr = read_sysreg_el2(elr);
 	u64 par = read_sysreg(par_el1);
 
 	if (read_sysreg(vttbr_el2)) {
@@ -230,11 +253,7 @@ void __hyp_text __noreturn __hyp_panic(void)
 	}
 
 	/* Call panic for real */
-	__hyp_do_panic(hyp_kern_va(str_va),
-		       spsr,  elr,
-		       read_sysreg(esr_el2),   read_sysreg(far_el2),
-		       read_sysreg(hpfar_el2), par,
-		       (void *)read_sysreg(tpidr_el2));
+	__hyp_call_panic()(spsr, elr, par);
 
 	unreachable();
 }
-- 
2.1.4

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#1316907 — [PATCH v2 05/21] arm64: KVM: VHE: Turn VTCR_EL2 setup into a reusable macro

On a VHE-capable system, there is no point in setting VTCR_EL2
at KVM init time. We can perfectly set it up when the kernel
boots, removing the need for a more complicated configuration.

In order to allow this, turn VTCR_EL2 setup into a macro that
we'll be able to reuse at boot time.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/kvm_mmu.h | 23 +++++++++++++++++++++++
 arch/arm64/kvm/hyp-init.S        | 18 +-----------------
 2 files changed, 24 insertions(+), 17 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 7364339..d3e6d7b 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -56,6 +56,29 @@
 
 #ifdef __ASSEMBLY__
 
+#include <asm/kvm_arm.h>
+
+.macro setup_vtcr tmp1, tmp2
+	mov	\tmp1, #(VTCR_EL2_FLAGS & 0xffff)
+	movk	\tmp1, #(VTCR_EL2_FLAGS >> 16), lsl #16
+	/*
+	 * Read the PARange bits from ID_AA64MMFR0_EL1 and set the PS bits in
+	 * VTCR_EL2.
+	 */
+	mrs	\tmp2, id_aa64mmfr0_el1
+	bfi	\tmp1, \tmp2, #16, #3
+	/*
+	 * Read the VMIDBits bits from ID_AA64MMFR1_EL1 and set the VS bit in
+	 * VTCR_EL2.
+	 */
+	mrs	\tmp2, ID_AA64MMFR1_EL1
+	ubfx	\tmp2, \tmp2, #5, #1
+	lsl	\tmp2, \tmp2, #VTCR_EL2_VS
+	orr	\tmp1, \tmp1, \tmp2
+
+	msr	vtcr_el2, \tmp1
+	isb
+.endm
 /*
  * Convert a kernel VA into a HYP VA.
  * reg: VA to be converted.
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 3e568dc..4143e2c 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -87,23 +87,7 @@ __do_hyp_init:
 #endif
 	msr	tcr_el2, x4
 
-	ldr	x4, =VTCR_EL2_FLAGS
-	/*
-	 * Read the PARange bits from ID_AA64MMFR0_EL1 and set the PS bits in
-	 * VTCR_EL2.
-	 */
-	mrs	x5, ID_AA64MMFR0_EL1
-	bfi	x4, x5, #16, #3
-	/*
-	 * Read the VMIDBits bits from ID_AA64MMFR1_EL1 and set the VS bit in
-	 * VTCR_EL2.
-	 */
-	mrs	x5, ID_AA64MMFR1_EL1
-	ubfx	x5, x5, #5, #1
-	lsl	x5, x5, #VTCR_EL2_VS
-	orr	x4, x4, x5
-
-	msr	vtcr_el2, x4
+	setup_vtcr x4, x5
 
 	mrs	x4, mair_el1
 	msr	mair_el2, x4
-- 
2.1.4

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#1316908 — [PATCH v2 11/21] arm64: KVM: VHE: Use unified system register accessors

Use the recently introduced unified system register accessors for
those sysregs that behave differently depending on VHE being in
use or not.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp/sysreg-sr.c | 84 +++++++++++++++++++++---------------------
 1 file changed, 42 insertions(+), 42 deletions(-)

diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index 61bad17..7d7d757 100644
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -37,34 +37,34 @@ static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
 	ctxt->sys_regs[TPIDRRO_EL0]	= read_sysreg(tpidrro_el0);
 	ctxt->sys_regs[TPIDR_EL1]	= read_sysreg(tpidr_el1);
 	ctxt->gp_regs.regs.sp		= read_sysreg(sp_el0);
-	ctxt->gp_regs.regs.pc		= read_sysreg(elr_el2);
-	ctxt->gp_regs.regs.pstate	= read_sysreg(spsr_el2);
+	ctxt->gp_regs.regs.pc		= read_sysreg_el2(elr);
+	ctxt->gp_regs.regs.pstate	= read_sysreg_el2(spsr);
 }
 
 static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
 {
 	ctxt->sys_regs[MPIDR_EL1]	= read_sysreg(vmpidr_el2);
 	ctxt->sys_regs[CSSELR_EL1]	= read_sysreg(csselr_el1);
-	ctxt->sys_regs[SCTLR_EL1]	= read_sysreg(sctlr_el1);
-	ctxt->sys_regs[CPACR_EL1]	= read_sysreg(cpacr_el1);
-	ctxt->sys_regs[TTBR0_EL1]	= read_sysreg(ttbr0_el1);
-	ctxt->sys_regs[TTBR1_EL1]	= read_sysreg(ttbr1_el1);
-	ctxt->sys_regs[TCR_EL1]		= read_sysreg(tcr_el1);
-	ctxt->sys_regs[ESR_EL1]		= read_sysreg(esr_el1);
-	ctxt->sys_regs[AFSR0_EL1]	= read_sysreg(afsr0_el1);
-	ctxt->sys_regs[AFSR1_EL1]	= read_sysreg(afsr1_el1);
-	ctxt->sys_regs[FAR_EL1]		= read_sysreg(far_el1);
-	ctxt->sys_regs[MAIR_EL1]	= read_sysreg(mair_el1);
-	ctxt->sys_regs[VBAR_EL1]	= read_sysreg(vbar_el1);
-	ctxt->sys_regs[CONTEXTIDR_EL1]	= read_sysreg(contextidr_el1);
-	ctxt->sys_regs[AMAIR_EL1]	= read_sysreg(amair_el1);
-	ctxt->sys_regs[CNTKCTL_EL1]	= read_sysreg(cntkctl_el1);
+	ctxt->sys_regs[SCTLR_EL1]	= read_sysreg_el1(sctlr);
+	ctxt->sys_regs[CPACR_EL1]	= read_sysreg_el1(cpacr);
+	ctxt->sys_regs[TTBR0_EL1]	= read_sysreg_el1(ttbr0);
+	ctxt->sys_regs[TTBR1_EL1]	= read_sysreg_el1(ttbr1);
+	ctxt->sys_regs[TCR_EL1]		= read_sysreg_el1(tcr);
+	ctxt->sys_regs[ESR_EL1]		= read_sysreg_el1(esr);
+	ctxt->sys_regs[AFSR0_EL1]	= read_sysreg_el1(afsr0);
+	ctxt->sys_regs[AFSR1_EL1]	= read_sysreg_el1(afsr1);
+	ctxt->sys_regs[FAR_EL1]		= read_sysreg_el1(far);
+	ctxt->sys_regs[MAIR_EL1]	= read_sysreg_el1(mair);
+	ctxt->sys_regs[VBAR_EL1]	= read_sysreg_el1(vbar);
+	ctxt->sys_regs[CONTEXTIDR_EL1]	= read_sysreg_el1(contextidr);
+	ctxt->sys_regs[AMAIR_EL1]	= read_sysreg_el1(amair);
+	ctxt->sys_regs[CNTKCTL_EL1]	= read_sysreg_el1(cntkctl);
 	ctxt->sys_regs[PAR_EL1]		= read_sysreg(par_el1);
 	ctxt->sys_regs[MDSCR_EL1]	= read_sysreg(mdscr_el1);
 
 	ctxt->gp_regs.sp_el1		= read_sysreg(sp_el1);
-	ctxt->gp_regs.elr_el1		= read_sysreg(elr_el1);
-	ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg(spsr_el1);
+	ctxt->gp_regs.elr_el1		= read_sysreg_el1(elr);
+	ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg_el1(spsr);
 }
 
 void __hyp_text __sysreg_save_host_state(struct kvm_cpu_context *ctxt)
@@ -86,34 +86,34 @@ static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctx
 	write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
 	write_sysreg(ctxt->sys_regs[TPIDR_EL1],	  tpidr_el1);
 	write_sysreg(ctxt->gp_regs.regs.sp,	  sp_el0);
-	write_sysreg(ctxt->gp_regs.regs.pc,	  elr_el2);
-	write_sysreg(ctxt->gp_regs.regs.pstate,	  spsr_el2);
+	write_sysreg_el2(ctxt->gp_regs.regs.pc,	  elr);
+	write_sysreg_el2(ctxt->gp_regs.regs.pstate, spsr);
 }
 
 static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
 {
-	write_sysreg(ctxt->sys_regs[MPIDR_EL1],	  vmpidr_el2);
-	write_sysreg(ctxt->sys_regs[CSSELR_EL1],  csselr_el1);
-	write_sysreg(ctxt->sys_regs[SCTLR_EL1],	  sctlr_el1);
-	write_sysreg(ctxt->sys_regs[CPACR_EL1],	  cpacr_el1);
-	write_sysreg(ctxt->sys_regs[TTBR0_EL1],	  ttbr0_el1);
-	write_sysreg(ctxt->sys_regs[TTBR1_EL1],	  ttbr1_el1);
-	write_sysreg(ctxt->sys_regs[TCR_EL1],	  tcr_el1);
-	write_sysreg(ctxt->sys_regs[ESR_EL1],	  esr_el1);
-	write_sysreg(ctxt->sys_regs[AFSR0_EL1],	  afsr0_el1);
-	write_sysreg(ctxt->sys_regs[AFSR1_EL1],	  afsr1_el1);
-	write_sysreg(ctxt->sys_regs[FAR_EL1],	  far_el1);
-	write_sysreg(ctxt->sys_regs[MAIR_EL1],	  mair_el1);
-	write_sysreg(ctxt->sys_regs[VBAR_EL1],	  vbar_el1);
-	write_sysreg(ctxt->sys_regs[CONTEXTIDR_EL1], contextidr_el1);
-	write_sysreg(ctxt->sys_regs[AMAIR_EL1],	  amair_el1);
-	write_sysreg(ctxt->sys_regs[CNTKCTL_EL1], cntkctl_el1);
-	write_sysreg(ctxt->sys_regs[PAR_EL1],	  par_el1);
-	write_sysreg(ctxt->sys_regs[MDSCR_EL1],	  mdscr_el1);
-
-	write_sysreg(ctxt->gp_regs.sp_el1,	sp_el1);
-	write_sysreg(ctxt->gp_regs.elr_el1,	elr_el1);
-	write_sysreg(ctxt->gp_regs.spsr[KVM_SPSR_EL1], spsr_el1);
+	write_sysreg(ctxt->sys_regs[MPIDR_EL1],		vmpidr_el2);
+	write_sysreg(ctxt->sys_regs[CSSELR_EL1],	csselr_el1);
+	write_sysreg_el1(ctxt->sys_regs[SCTLR_EL1],	sctlr);
+	write_sysreg_el1(ctxt->sys_regs[CPACR_EL1],	cpacr);
+	write_sysreg_el1(ctxt->sys_regs[TTBR0_EL1],	ttbr0);
+	write_sysreg_el1(ctxt->sys_regs[TTBR1_EL1],	ttbr1);
+	write_sysreg_el1(ctxt->sys_regs[TCR_EL1],	tcr);
+	write_sysreg_el1(ctxt->sys_regs[ESR_EL1],	esr);
+	write_sysreg_el1(ctxt->sys_regs[AFSR0_EL1],	afsr0);
+	write_sysreg_el1(ctxt->sys_regs[AFSR1_EL1],	afsr1);
+	write_sysreg_el1(ctxt->sys_regs[FAR_EL1],	far);
+	write_sysreg_el1(ctxt->sys_regs[MAIR_EL1],	mair);
+	write_sysreg_el1(ctxt->sys_regs[VBAR_EL1],	vbar);
+	write_sysreg_el1(ctxt->sys_regs[CONTEXTIDR_EL1],contextidr);
+	write_sysreg_el1(ctxt->sys_regs[AMAIR_EL1],	amair);
+	write_sysreg_el1(ctxt->sys_regs[CNTKCTL_EL1], 	cntkctl);
+	write_sysreg(ctxt->sys_regs[PAR_EL1],		par_el1);
+	write_sysreg(ctxt->sys_regs[MDSCR_EL1],		mdscr_el1);
+
+	write_sysreg(ctxt->gp_regs.sp_el1,		sp_el1);
+	write_sysreg_el1(ctxt->gp_regs.elr_el1,		elr);
+	write_sysreg_el1(ctxt->gp_regs.spsr[KVM_SPSR_EL1],spsr);
 }
 
 void __hyp_text __sysreg_restore_host_state(struct kvm_cpu_context *ctxt)
-- 
2.1.4

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#1316912 — [PATCH v2 03/21] arm64: Add ARM64_HAS_VIRT_HOST_EXTN feature

Add a new ARM64_HAS_VIRT_HOST_EXTN features to indicate that the
CPU has the ARMv8.1 VHE capability.

This will be used to trigger kernel patching in KVM.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/cpufeature.h |  3 ++-
 arch/arm64/kernel/cpufeature.c      | 15 +++++++++++++--
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 8f271b8..c705d6a 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -30,8 +30,9 @@
 #define ARM64_HAS_LSE_ATOMICS			5
 #define ARM64_WORKAROUND_CAVIUM_23154		6
 #define ARM64_WORKAROUND_834220			7
+#define ARM64_HAS_VIRT_HOST_EXTN		8
 
-#define ARM64_NCAPS				8
+#define ARM64_NCAPS				9
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 5c90aa4..8d3961e 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -26,6 +26,9 @@
 #include <asm/cpu_ops.h>
 #include <asm/processor.h>
 #include <asm/sysreg.h>
+#include <asm/virt.h>
+
+#include <linux/irqchip/arm-gic-v3.h>
 
 unsigned long elf_hwcap __read_mostly;
 EXPORT_SYMBOL_GPL(elf_hwcap);
@@ -587,8 +590,6 @@ u64 read_system_reg(u32 id)
 	return regp->sys_val;
 }
 
-#include <linux/irqchip/arm-gic-v3.h>
-
 static bool
 feature_matches(u64 reg, const struct arm64_cpu_capabilities *entry)
 {
@@ -621,6 +622,11 @@ static bool has_useable_gicv3_cpuif(const struct arm64_cpu_capabilities *entry)
 	return has_sre;
 }
 
+static bool runs_at_el2(const struct arm64_cpu_capabilities *entry)
+{
+	return is_kernel_in_hyp_mode();
+}
+
 static const struct arm64_cpu_capabilities arm64_features[] = {
 	{
 		.desc = "GIC system register CPU interface",
@@ -651,6 +657,11 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.min_field_value = 2,
 	},
 #endif /* CONFIG_AS_LSE && CONFIG_ARM64_LSE_ATOMICS */
+	{
+		.desc = "Virtualization Host Extensions",
+		.capability = ARM64_HAS_VIRT_HOST_EXTN,
+		.matches = runs_at_el2,
+	},
 	{},
 };
 
-- 
2.1.4

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#1316915 — [PATCH v2 08/21] arm64: KVM: VHE: Introduce unified system register accessors

VHE brings its own bag of new system registers, or rather system
register accessors, as it define new ways to access both guest
and host system registers. For example, from the host:

- The host TCR_EL2 register is accessed using the TCR_EL1 accessor
- The guest TCR_EL1 register is accessed using the TCR_EL12 accessor

Obviously, this is confusing. A way to somehow reduce the complexity
of writing code for both ARMv8 and ARMv8.1 is to use a set of unified
accessors that will generate the right sysreg, depending on the mode
the CPU is running in. For example:

- read_sysreg_el1(tcr) will use TCR_EL1 on ARMv8, and TCR_EL12 on
  ARMv8.1 with VHE.
- read_sysreg_el2(tcr) will use TCR_EL2 on ARMv8, and TCR_EL1 on
  ARMv8.1 with VHE.

We end up with three sets of accessors ({read,write}_sysreg_el[012])
that can be directly used from C code. We take this opportunity to
also add the definition for the new VHE sysregs.(

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp/hyp.h | 72 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
index fc502f3..744c919 100644
--- a/arch/arm64/kvm/hyp/hyp.h
+++ b/arch/arm64/kvm/hyp/hyp.h
@@ -48,6 +48,78 @@ static inline unsigned long __hyp_kern_va(unsigned long v)
 
 #define hyp_kern_va(v) (typeof(v))(__hyp_kern_va((unsigned long)(v)))
 
+#define read_sysreg_elx(r,nvh,vh)					\
+	({								\
+		u64 reg;						\
+		asm volatile(ALTERNATIVE("mrs %0, " __stringify(r##nvh),\
+					 "mrs_s %0, " __stringify(r##vh),\
+					 ARM64_HAS_VIRT_HOST_EXTN)	\
+			     : "=r" (reg));				\
+		reg;							\
+	})
+
+#define write_sysreg_elx(v,r,nvh,vh)					\
+	do {								\
+		u64 __val = (u64)(v);					\
+		asm volatile(ALTERNATIVE("msr " __stringify(r##nvh) ", %x0",\
+					 "msr_s " __stringify(r##vh) ", %x0",\
+					 ARM64_HAS_VIRT_HOST_EXTN)	\
+					 : : "rZ" (__val));		\
+	} while (0)
+
+/*
+ * Unified accessors for registers that have a different encoding
+ * between VHE and non-VHE. They must be specified without their "ELx"
+ * encoding.
+ */
+#define read_sysreg_el2(r)						\
+	({								\
+		u64 reg;						\
+		asm volatile(ALTERNATIVE("mrs %0, " __stringify(r##_EL2),\
+					 "mrs %0, " __stringify(r##_EL1),\
+					 ARM64_HAS_VIRT_HOST_EXTN)	\
+			     : "=r" (reg));				\
+		reg;							\
+	})
+
+#define write_sysreg_el2(v,r)						\
+	do {								\
+		u64 __val = (u64)(v);					\
+		asm volatile(ALTERNATIVE("msr " __stringify(r##_EL2) ", %x0",\
+					 "msr " __stringify(r##_EL1) ", %x0",\
+					 ARM64_HAS_VIRT_HOST_EXTN)	\
+					 : : "rZ" (__val));		\
+	} while (0)
+
+#define read_sysreg_el0(r)	read_sysreg_elx(r, _EL0, _EL02)
+#define write_sysreg_el0(v,r)	write_sysreg_elx(v, r, _EL0, _EL02)
+#define read_sysreg_el1(r)	read_sysreg_elx(r, _EL1, _EL12)
+#define write_sysreg_el1(v,r)	write_sysreg_elx(v, r, _EL1, _EL12)
+
+/* The VHE specific system registers and their encoding */
+#define sctlr_EL12              sys_reg(3, 5, 1, 0, 0)
+#define cpacr_EL12              sys_reg(3, 5, 1, 0, 2)
+#define ttbr0_EL12              sys_reg(3, 5, 2, 0, 0)
+#define ttbr1_EL12              sys_reg(3, 5, 2, 0, 1)
+#define tcr_EL12                sys_reg(3, 5, 2, 0, 2)
+#define afsr0_EL12              sys_reg(3, 5, 5, 1, 0)
+#define afsr1_EL12              sys_reg(3, 5, 5, 1, 1)
+#define esr_EL12                sys_reg(3, 5, 5, 2, 0)
+#define far_EL12                sys_reg(3, 5, 6, 0, 0)
+#define mair_EL12               sys_reg(3, 5, 10, 2, 0)
+#define amair_EL12              sys_reg(3, 5, 10, 3, 0)
+#define vbar_EL12               sys_reg(3, 5, 12, 0, 0)
+#define contextidr_EL12         sys_reg(3, 5, 13, 0, 1)
+#define cntkctl_EL12            sys_reg(3, 5, 14, 1, 0)
+#define cntp_tval_EL02          sys_reg(3, 5, 14, 2, 0)
+#define cntp_ctl_EL02           sys_reg(3, 5, 14, 2, 1)
+#define cntp_cval_EL02          sys_reg(3, 5, 14, 2, 2)
+#define cntv_tval_EL02          sys_reg(3, 5, 14, 3, 0)
+#define cntv_ctl_EL02           sys_reg(3, 5, 14, 3, 1)
+#define cntv_cval_EL02          sys_reg(3, 5, 14, 3, 2)
+#define spsr_EL12               sys_reg(3, 5, 4, 0, 0)
+#define elr_EL12                sys_reg(3, 5, 4, 0, 1)
+
 /**
  * hyp_alternate_select - Generates patchable code sequences that are
  * used to switch between two implementations of a function, depending
-- 
2.1.4

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#1316918 — [PATCH v2 04/21] arm64: KVM: Skip HYP setup when already running in HYP

With the kernel running at EL2, there is no point trying to
configure page tables for HYP, as the kernel is already mapped.

Take this opportunity to refactor the whole init a bit, allowing
the various parts of the hypervisor bringup to be split across
multiple functions.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kvm/arm.c | 151 +++++++++++++++++++++++++++++++++--------------------
 arch/arm/kvm/mmu.c |   7 +++
 2 files changed, 100 insertions(+), 58 deletions(-)

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index dda1959..66e2d04 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -1035,6 +1035,67 @@ static inline void hyp_cpu_pm_init(void)
 }
 #endif
 
+static void teardown_common_resources(void)
+{
+	free_percpu(kvm_host_cpu_state);
+}
+
+static int init_common_resources(void)
+{
+	kvm_host_cpu_state = alloc_percpu(kvm_cpu_context_t);
+	if (!kvm_host_cpu_state) {
+		kvm_err("Cannot allocate host CPU state\n");
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int init_subsystems(void)
+{
+	int err;
+
+	/*
+	 * Init HYP view of VGIC
+	 */
+	err = kvm_vgic_hyp_init();
+	switch (err) {
+	case 0:
+		vgic_present = true;
+		break;
+	case -ENODEV:
+	case -ENXIO:
+		vgic_present = false;
+		break;
+	default:
+		return err;
+	}
+
+	/*
+	 * Init HYP architected timer support
+	 */
+	err = kvm_timer_hyp_init();
+	if (err)
+		return err;
+
+	kvm_perf_init();
+	kvm_coproc_table_init();
+
+	return 0;
+}
+
+static void teardown_hyp_mode(void)
+{
+	int cpu;
+
+	if (is_kernel_in_hyp_mode())
+		return;
+
+	free_hyp_pgds();
+	for_each_possible_cpu(cpu)
+		free_page(per_cpu(kvm_arm_hyp_stack_page, cpu));
+}
+
 /**
  * Inits Hyp-mode on all online CPUs
  */
@@ -1043,6 +1104,9 @@ static int init_hyp_mode(void)
 	int cpu;
 	int err = 0;
 
+	if (is_kernel_in_hyp_mode())
+		return 0;
+
 	/*
 	 * Allocate Hyp PGD and setup Hyp identity mapping
 	 */
@@ -1065,7 +1129,7 @@ static int init_hyp_mode(void)
 		stack_page = __get_free_page(GFP_KERNEL);
 		if (!stack_page) {
 			err = -ENOMEM;
-			goto out_free_stack_pages;
+			goto out_err;
 		}
 
 		per_cpu(kvm_arm_hyp_stack_page, cpu) = stack_page;
@@ -1077,13 +1141,13 @@ static int init_hyp_mode(void)
 	err = create_hyp_mappings(__kvm_hyp_code_start, __kvm_hyp_code_end);
 	if (err) {
 		kvm_err("Cannot map world-switch code\n");
-		goto out_free_mappings;
+		goto out_err;
 	}
 
 	err = create_hyp_mappings(__start_rodata, __end_rodata);
 	if (err) {
 		kvm_err("Cannot map rodata section\n");
-		goto out_free_mappings;
+		goto out_err;
 	}
 
 	/*
@@ -1095,20 +1159,10 @@ static int init_hyp_mode(void)
 
 		if (err) {
 			kvm_err("Cannot map hyp stack\n");
-			goto out_free_mappings;
+			goto out_err;
 		}
 	}
 
-	/*
-	 * Map the host CPU structures
-	 */
-	kvm_host_cpu_state = alloc_percpu(kvm_cpu_context_t);
-	if (!kvm_host_cpu_state) {
-		err = -ENOMEM;
-		kvm_err("Cannot allocate host CPU state\n");
-		goto out_free_mappings;
-	}
-
 	for_each_possible_cpu(cpu) {
 		kvm_cpu_context_t *cpu_ctxt;
 
@@ -1117,7 +1171,7 @@ static int init_hyp_mode(void)
 
 		if (err) {
 			kvm_err("Cannot map host CPU state: %d\n", err);
-			goto out_free_context;
+			goto out_err;
 		}
 	}
 
@@ -1126,34 +1180,22 @@ static int init_hyp_mode(void)
 	 */
 	on_each_cpu(cpu_init_hyp_mode, NULL, 1);
 
-	/*
-	 * Init HYP view of VGIC
-	 */
-	err = kvm_vgic_hyp_init();
-	switch (err) {
-	case 0:
-		vgic_present = true;
-		break;
-	case -ENODEV:
-	case -ENXIO:
-		vgic_present = false;
-		break;
-	default:
-		goto out_free_context;
-	}
-
-	/*
-	 * Init HYP architected timer support
-	 */
-	err = kvm_timer_hyp_init();
-	if (err)
-		goto out_free_context;
-
 #ifndef CONFIG_HOTPLUG_CPU
 	free_boot_hyp_pgd();
 #endif
 
-	kvm_perf_init();
+	cpu_notifier_register_begin();
+
+	err = __register_cpu_notifier(&hyp_init_cpu_nb);
+
+	cpu_notifier_register_done();
+
+	if (err) {
+		kvm_err("Cannot register HYP init CPU notifier (%d)\n", err);
+		goto out_err;
+	}
+
+	hyp_cpu_pm_init();
 
 	/* set size of VMID supported by CPU */
 	kvm_vmid_bits = kvm_get_vmid_bits();
@@ -1162,14 +1204,9 @@ static int init_hyp_mode(void)
 	kvm_info("Hyp mode initialized successfully\n");
 
 	return 0;
-out_free_context:
-	free_percpu(kvm_host_cpu_state);
-out_free_mappings:
-	free_hyp_pgds();
-out_free_stack_pages:
-	for_each_possible_cpu(cpu)
-		free_page(per_cpu(kvm_arm_hyp_stack_page, cpu));
+
 out_err:
+	teardown_hyp_mode();
 	kvm_err("error initializing Hyp mode: %d\n", err);
 	return err;
 }
@@ -1213,26 +1250,24 @@ int kvm_arch_init(void *opaque)
 		}
 	}
 
-	cpu_notifier_register_begin();
+	err = init_common_resources();
+	if (err)
+		return err;
 
 	err = init_hyp_mode();
 	if (err)
 		goto out_err;
 
-	err = __register_cpu_notifier(&hyp_init_cpu_nb);
-	if (err) {
-		kvm_err("Cannot register HYP init CPU notifier (%d)\n", err);
-		goto out_err;
-	}
-
-	cpu_notifier_register_done();
-
-	hyp_cpu_pm_init();
+	err = init_subsystems();
+	if (err)
+		goto out_hyp;
 
-	kvm_coproc_table_init();
 	return 0;
+
+out_hyp:
+	teardown_hyp_mode();
 out_err:
-	cpu_notifier_register_done();
+	teardown_common_resources();
 	return err;
 }
 
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index aba61fd..920d0c3 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -28,6 +28,7 @@
 #include <asm/kvm_mmio.h>
 #include <asm/kvm_asm.h>
 #include <asm/kvm_emulate.h>
+#include <asm/virt.h>
 
 #include "trace.h"
 
@@ -598,6 +599,9 @@ int create_hyp_mappings(void *from, void *to)
 	unsigned long start = KERN_TO_HYP((unsigned long)from);
 	unsigned long end = KERN_TO_HYP((unsigned long)to);
 
+	if (is_kernel_in_hyp_mode())
+		return 0;
+
 	start = start & PAGE_MASK;
 	end = PAGE_ALIGN(end);
 
@@ -630,6 +634,9 @@ int create_hyp_io_mappings(void *from, void *to, phys_addr_t phys_addr)
 	unsigned long start = KERN_TO_HYP((unsigned long)from);
 	unsigned long end = KERN_TO_HYP((unsigned long)to);
 
+	if (is_kernel_in_hyp_mode())
+		return 0;
+
 	/* Check for a valid kernel IO mapping */
 	if (!is_vmalloc_addr(from) || !is_vmalloc_addr(to - 1))
 		return -EINVAL;
-- 
2.1.4

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#1316924 — [PATCH v2 02/21] arm64: Allow the arch timer to use the HYP timer

With the ARMv8.1 VHE, the kernel can run in HYP mode, and thus
use the HYP timer instead of the normal guest timer in a mostly
transparent way, except for the interrupt line.

This patch reworks the arch timer code to allow the selection of
the HYP PPI, possibly falling back to the guest timer if not
available.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/clocksource/arm_arch_timer.c | 96 ++++++++++++++++++++++--------------
 1 file changed, 59 insertions(+), 37 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index c64d543..ffe9d1c 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -67,7 +67,7 @@ static int arch_timer_ppi[MAX_TIMER_PPI];
 
 static struct clock_event_device __percpu *arch_timer_evt;
 
-static bool arch_timer_use_virtual = true;
+static enum ppi_nr arch_timer_uses_ppi = VIRT_PPI;
 static bool arch_timer_c3stop;
 static bool arch_timer_mem_use_virtual;
 
@@ -263,14 +263,20 @@ static void __arch_timer_setup(unsigned type,
 		clk->name = "arch_sys_timer";
 		clk->rating = 450;
 		clk->cpumask = cpumask_of(smp_processor_id());
-		if (arch_timer_use_virtual) {
-			clk->irq = arch_timer_ppi[VIRT_PPI];
+		clk->irq = arch_timer_ppi[arch_timer_uses_ppi];
+		switch (arch_timer_uses_ppi) {
+		case VIRT_PPI:
 			clk->set_state_shutdown = arch_timer_shutdown_virt;
 			clk->set_next_event = arch_timer_set_next_event_virt;
-		} else {
-			clk->irq = arch_timer_ppi[PHYS_SECURE_PPI];
+			break;
+		case PHYS_SECURE_PPI:
+		case PHYS_NONSECURE_PPI:
+		case HYP_PPI:
 			clk->set_state_shutdown = arch_timer_shutdown_phys;
 			clk->set_next_event = arch_timer_set_next_event_phys;
+			break;
+		default:
+			BUG();
 		}
 	} else {
 		clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
@@ -338,17 +344,20 @@ static void arch_counter_set_user_access(void)
 	arch_timer_set_cntkctl(cntkctl);
 }
 
+static bool arch_timer_has_nonsecure_ppi(void)
+{
+	return (arch_timer_uses_ppi == PHYS_SECURE_PPI &&
+		arch_timer_ppi[PHYS_NONSECURE_PPI]);
+}
+
 static int arch_timer_setup(struct clock_event_device *clk)
 {
 	__arch_timer_setup(ARCH_CP15_TIMER, clk);
 
-	if (arch_timer_use_virtual)
-		enable_percpu_irq(arch_timer_ppi[VIRT_PPI], 0);
-	else {
-		enable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI], 0);
-		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
-			enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], 0);
-	}
+	enable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], 0);
+
+	if (arch_timer_has_nonsecure_ppi())
+		enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], 0);
 
 	arch_counter_set_user_access();
 	if (IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM))
@@ -390,7 +399,7 @@ static void arch_timer_banner(unsigned type)
 		     (unsigned long)arch_timer_rate / 1000000,
 		     (unsigned long)(arch_timer_rate / 10000) % 100,
 		     type & ARCH_CP15_TIMER ?
-			arch_timer_use_virtual ? "virt" : "phys" :
+		     (arch_timer_uses_ppi == VIRT_PPI) ? "virt" : "phys" :
 			"",
 		     type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ?  "/" : "",
 		     type & ARCH_MEM_TIMER ?
@@ -460,7 +469,7 @@ static void __init arch_counter_register(unsigned type)
 
 	/* Register the CP15 based counter if we have one */
 	if (type & ARCH_CP15_TIMER) {
-		if (IS_ENABLED(CONFIG_ARM64) || arch_timer_use_virtual)
+		if (IS_ENABLED(CONFIG_ARM64) || arch_timer_uses_ppi == VIRT_PPI)
 			arch_timer_read_counter = arch_counter_get_cntvct;
 		else
 			arch_timer_read_counter = arch_counter_get_cntpct;
@@ -490,13 +499,9 @@ static void arch_timer_stop(struct clock_event_device *clk)
 	pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n",
 		 clk->irq, smp_processor_id());
 
-	if (arch_timer_use_virtual)
-		disable_percpu_irq(arch_timer_ppi[VIRT_PPI]);
-	else {
-		disable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI]);
-		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
-			disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]);
-	}
+	disable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi]);
+	if (arch_timer_has_nonsecure_ppi())
+		disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]);
 
 	clk->set_state_shutdown(clk);
 }
@@ -562,12 +567,14 @@ static int __init arch_timer_register(void)
 		goto out;
 	}
 
-	if (arch_timer_use_virtual) {
-		ppi = arch_timer_ppi[VIRT_PPI];
+	ppi = arch_timer_ppi[arch_timer_uses_ppi];
+	switch (arch_timer_uses_ppi) {
+	case VIRT_PPI:
 		err = request_percpu_irq(ppi, arch_timer_handler_virt,
 					 "arch_timer", arch_timer_evt);
-	} else {
-		ppi = arch_timer_ppi[PHYS_SECURE_PPI];
+		break;
+	case PHYS_SECURE_PPI:
+	case PHYS_NONSECURE_PPI:
 		err = request_percpu_irq(ppi, arch_timer_handler_phys,
 					 "arch_timer", arch_timer_evt);
 		if (!err && arch_timer_ppi[PHYS_NONSECURE_PPI]) {
@@ -578,6 +585,13 @@ static int __init arch_timer_register(void)
 				free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
 						arch_timer_evt);
 		}
+		break;
+	case HYP_PPI:
+		err = request_percpu_irq(ppi, arch_timer_handler_phys,
+					 "arch_timer", arch_timer_evt);
+		break;
+	default:
+		BUG();
 	}
 
 	if (err) {
@@ -602,15 +616,10 @@ static int __init arch_timer_register(void)
 out_unreg_notify:
 	unregister_cpu_notifier(&arch_timer_cpu_nb);
 out_free_irq:
-	if (arch_timer_use_virtual)
-		free_percpu_irq(arch_timer_ppi[VIRT_PPI], arch_timer_evt);
-	else {
-		free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
+	free_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], arch_timer_evt);
+	if (arch_timer_has_nonsecure_ppi())
+		free_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI],
 				arch_timer_evt);
-		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
-			free_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI],
-					arch_timer_evt);
-	}
 
 out_free:
 	free_percpu(arch_timer_evt);
@@ -697,12 +706,25 @@ static void __init arch_timer_init(void)
 	 *
 	 * If no interrupt provided for virtual timer, we'll have to
 	 * stick to the physical timer. It'd better be accessible...
+	 *
+	 * On ARMv8.1 with VH extensions, the kernel runs in HYP. VHE
+	 * accesses to CNTP_*_EL1 registers are silently redirected to
+	 * their CNTHP_*_EL2 counterparts, and use a different PPI
+	 * number.
 	 */
 	if (is_hyp_mode_available() || !arch_timer_ppi[VIRT_PPI]) {
-		arch_timer_use_virtual = false;
+		bool has_ppi;
+
+		if (is_kernel_in_hyp_mode()) {
+			arch_timer_uses_ppi = HYP_PPI;
+			has_ppi = !!arch_timer_ppi[HYP_PPI];
+		} else {
+			arch_timer_uses_ppi = PHYS_SECURE_PPI;
+			has_ppi = (!!arch_timer_ppi[PHYS_SECURE_PPI] ||
+				   !!arch_timer_ppi[PHYS_NONSECURE_PPI]);
+		}
 
-		if (!arch_timer_ppi[PHYS_SECURE_PPI] ||
-		    !arch_timer_ppi[PHYS_NONSECURE_PPI]) {
+		if (!has_ppi) {
 			pr_warn("arch_timer: No interrupt available, giving up\n");
 			return;
 		}
@@ -735,7 +757,7 @@ static void __init arch_timer_of_init(struct device_node *np)
 	 */
 	if (IS_ENABLED(CONFIG_ARM) &&
 	    of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
-			arch_timer_use_virtual = false;
+		arch_timer_uses_ppi = PHYS_SECURE_PPI;
 
 	arch_timer_init();
 }
-- 
2.1.4

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#1316930 — [PATCH v2 13/21] arm64: KVM: VHE: Make __fpsimd_enabled VHE aware

As non-VHE and VHE have different ways to express the trapping of
FPSIMD registers to EL2, make __fpsimd_enabled a patchable predicate
and provide a VHE implementation.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp/hyp.h    |  5 +----
 arch/arm64/kvm/hyp/switch.c | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
index 5dfa883..44eaff7 100644
--- a/arch/arm64/kvm/hyp/hyp.h
+++ b/arch/arm64/kvm/hyp/hyp.h
@@ -171,10 +171,7 @@ void __debug_cond_restore_host_state(struct kvm_vcpu *vcpu);
 
 void __fpsimd_save_state(struct user_fpsimd_state *fp_regs);
 void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs);
-static inline bool __fpsimd_enabled(void)
-{
-	return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP);
-}
+bool __fpsimd_enabled(void);
 
 u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt);
 void __noreturn __hyp_do_panic(unsigned long, ...);
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 9071dee..6f264dc 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -17,6 +17,25 @@
 
 #include "hyp.h"
 
+static bool __hyp_text __fpsimd_enabled_nvhe(void)
+{
+	return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP);
+}
+
+static bool __hyp_text __fpsimd_enabled_vhe(void)
+{
+	return !!(read_sysreg(cpacr_el1) & (3 << 20));
+}
+
+static hyp_alternate_select(__fpsimd_is_enabled,
+			    __fpsimd_enabled_nvhe, __fpsimd_enabled_vhe,
+			    ARM64_HAS_VIRT_HOST_EXTN);
+
+bool __hyp_text __fpsimd_enabled(void)
+{
+	return __fpsimd_is_enabled()();
+}
+
 static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
 {
 	u64 val;
-- 
2.1.4

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