KVM: arm64: Discard any SVE state when entering KVM guests

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Since 8383741ab2 (KVM: arm64: Get rid of host SVE tracking/saving)
KVM has not tracked the host SVE state, relying on the fact that we
currently disable SVE whenever we perform a syscall. This may not be true
in future since performance optimisation may result in us keeping SVE
enabled in order to avoid needing to take access traps to reenable it.
Handle this by clearing TIF_SVE and converting the stored task state to
FPSIMD format when preparing to run the guest.  This is done with a new
call fpsimd_kvm_prepare() to keep the direct state manipulation
functions internal to fpsimd.c.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221115094640.112848-2-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

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Mark Brown 2022-11-15 09:46:33 +00:00 • committed by Will Deacon

parent f0c4d9fc9c

commit 93ae6b01ba

3 changed files with 26 additions and 1 deletions

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1

arch/arm64/include/asm/fpsimd.h

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23

arch/arm64/kernel/fpsimd.c

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3

arch/arm64/kvm/fpsimd.c

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