Messages in this thread | | | From | Dave Martin <> | Subject | [PATCH v5 00/14] KVM: arm64: Optimise FPSIMD context switching | Date | Fri, 4 May 2018 17:05:21 +0100 |
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Note: Most of these patches are Arm-specific. People not Cc'd on the whole series can find it in the linux-arm-kernel archive [3].
This series aims to improve the way FPSIMD context is handled by KVM, building on the previous RFC v4 [1].
Patches 1-2 are picked from a separate RFC series [2] since they introduce a helper I wanted to use here.
The main changes since RFC v4 are:
* Rebased to -rc3.
* Patches 1-2 pulled into series from [2], and other patches modified to use it.
* Redundant additions by patch 3 that were reverted by other patches are now gone.
* New patches 12-14 move the call to __hyp_switch_fpsimd() out of asm completely, moving it to the fixup_guest_exit() path instead. This should significantly cleaner, but does add a bit of overhead to FPSIMD trapping.
This is presented as an independent change in case people want to benchmark with/without.
Other minor changes as noted.
Some testing done on Juno and the Arm fast model (arm64), including combinations of (non-)SVE and (non-)VHE configurations.
Cheers ---Dave
[1] [RFC PATCH 0/8] KVM: arm64: Optimise FPSIMD context switching http://lists.infradead.org/pipermail/linux-arm-kernel/2018-April/572781.html
[2] [RFC PATCH 0/6] Simplify setting thread flags to a particular value https://lkml.org/lkml/2018/4/19/225
[3] linux-arm-kernel archive http://lists.infradead.org/pipermail/linux-arm-kernel/2018-May/thread.html
Christoffer Dall (1): KVM: arm/arm64: Introduce kvm_arch_vcpu_run_pid_change
Dave Martin (13): thread_info: Add update_thread_flag() helpers arm64: Use update{,_tsk}_thread_flag() KVM: arm64: Convert lazy FPSIMD context switch trap to C arm64: fpsimd: Generalise context saving for non-task contexts KVM: arm64: Optimise FPSIMD handling to reduce guest/host thrashing arm64/sve: Move read_zcr_features() out of cpufeature.h arm64/sve: Switch sve_pffr() argument from task to thread arm64/sve: Move sve_pffr() to fpsimd.h and make inline KVM: arm64: Save host SVE context as appropriate KVM: arm64: Remove eager host SVE state saving KVM: arm64: Remove redundant *exit_code changes in fpsimd_guest_exit() KVM: arm64: Fold redundant exit code checks out of fixup_guest_exit() KVM: arm64: Invoke FPSIMD context switch trap from C
arch/arm/include/asm/kvm_host.h | 9 ++- arch/arm64/Kconfig | 7 +++ arch/arm64/include/asm/cpufeature.h | 29 --------- arch/arm64/include/asm/fpsimd.h | 20 ++++++ arch/arm64/include/asm/kvm_host.h | 22 ++++--- arch/arm64/include/asm/processor.h | 2 + arch/arm64/kernel/fpsimd.c | 120 +++++++++++++++++------------------ arch/arm64/kernel/ptrace.c | 1 + arch/arm64/kvm/Kconfig | 1 + arch/arm64/kvm/Makefile | 2 +- arch/arm64/kvm/fpsimd.c | 105 +++++++++++++++++++++++++++++++ arch/arm64/kvm/hyp/entry.S | 43 ------------- arch/arm64/kvm/hyp/hyp-entry.S | 19 ------ arch/arm64/kvm/hyp/switch.c | 121 +++++++++++++++++++++++++----------- include/linux/kvm_host.h | 9 +++ include/linux/sched.h | 6 ++ include/linux/thread_info.h | 11 ++++ virt/kvm/Kconfig | 3 + virt/kvm/arm/arm.c | 25 +++++++- virt/kvm/kvm_main.c | 7 ++- 20 files changed, 360 insertions(+), 202 deletions(-) create mode 100644 arch/arm64/kvm/fpsimd.c
-- 2.1.4
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