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Subject[PATCH v5 00/14] KVM: arm64: Optimise FPSIMD context switching
Date
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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