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| author | Mark Brown <broonie@kernel.org> | 2023-03-07 17:37:14 +0000 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2023-04-21 13:46:20 +0100 |
| commit | 4c181e3d352e9280c84fb4b4c7a8940ce005374e (patch) | |
| tree | a6b4102317e80bc45c1447383897aa09201784a1 | |
| parent | 3d1793562858f2bc42cc722fe00ec9b2ff0618e1 (diff) | |
| download | linux-stable-4c181e3d352e9280c84fb4b4c7a8940ce005374e.tar.gz linux-stable-4c181e3d352e9280c84fb4b4c7a8940ce005374e.tar.bz2 linux-stable-4c181e3d352e9280c84fb4b4c7a8940ce005374e.zip | |
KVM: arm64: Document check for TIF_FOREIGN_FPSTATE
In kvm_arch_vcpu_load_fp() we unconditionally set the current FP state
to FP_STATE_HOST_OWNED, this will be overridden to FP_STATE_NONE if
TIF_FOREIGN_FPSTATE is set but the check is deferred until
kvm_arch_vcpu_ctxflush_fp() where we are no longer preemptable. Add a
comment to this effect to help avoid people being concerned about the
lack of a check and discover where the check is done.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221214-kvm-arm64-sme-context-switch-v2-1-57ba0082e9ff@kernel.org
| -rw-r--r-- | arch/arm64/kvm/fpsimd.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index 1279949599b5..3fd0ce6a3500 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -81,6 +81,11 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) fpsimd_kvm_prepare(); + /* + * We will check TIF_FOREIGN_FPSTATE just before entering the + * guest in kvm_arch_vcpu_ctxflush_fp() and override this to + * FP_STATE_FREE if the flag set. + */ vcpu->arch.fp_state = FP_STATE_HOST_OWNED; vcpu_clear_flag(vcpu, HOST_SVE_ENABLED); |