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

From Marc Zyngier <marc.zyngier@arm.com>
Newsgroups linux.kernel
Subject [PATCH v2 04/21] arm64: KVM: Skip HYP setup when already running in HYP
Date 2016-01-25 17:10 +0100
Message-ID <qURSi-6uy-29@gated-at.bofh.it> (permalink)
References <qURIC-68y-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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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Thread

[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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