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Groups > linux.kernel > #1317221
| From | Marc Zyngier <marc.zyngier@arm.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v2 00/21] arm64: Virtualization Host Extension support |
| Date | 2016-01-25 20:20 +0100 |
| Message-ID | <qUUQ9-cl-1@gated-at.bofh.it> (permalink) |
| References | <qURIC-68y-3@gated-at.bofh.it> <qUSbE-6CP-39@gated-at.bofh.it> <qUSlk-6Ia-33@gated-at.bofh.it> <qUSv1-6M7-51@gated-at.bofh.it> |
| Organization | ARM Ltd |
On 25/01/16 16:44, Will Deacon wrote: > On Mon, Jan 25, 2016 at 04:37:39PM +0000, Marc Zyngier wrote: >> On 25/01/16 16:26, Will Deacon wrote: >>> On Mon, Jan 25, 2016 at 03:53:34PM +0000, Marc Zyngier wrote: >>>> 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. >>> >>> [...] >>> >>>> 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(-) >>> >>> Have you tried hw_breakpoint/perf/ptrace with these changes? I was under >>> the impression that the debug architecture was aware of E2H and did need >>> some changes made. I know you say that GDB is broken anyway, but we should >>> check that the kernel does the right thing if userspace pokes it the >>> right way. >> >> I did use HW breakpoints on the model by hacking the host kernel to >> return Debug Version 6 instead of 7, and things seem to work as >> expected. strace also works out of the box. >> >> As for perf, did you have something precise in mind? > > It would be worth trying things like the filter options on perf events > (perf stat -e cycles:k to count cycles in kernel space) and also > breakpoints (perf stat -e mem:<addr>:rwx on kernel addresses). So indeed these didn't work (perf reported 0 for kernel accesses). The fixes are pretty trivial, and I've put them on top of my kvm-arm64/vhe branch, for those who want to have a look. Thanks, M. -- Jazz is not dead. It just smells funny...
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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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