The handling for FPSIMD/SVE traps is multi stage and involves some trap
manipulation which isn't quite so immediately obvious as might be desired
so add a few more comments.
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
arch/arm64/kvm/hyp/include/hyp/switch.h | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 58e14f8ead23..1995808d8766 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -173,6 +173,8 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
return false;
/* Valid trap. Switch the context: */
+
+ /* First disable enough traps to allow us to update the registers */
if (has_vhe()) {
reg = CPACR_EL1_FPEN;
if (sve_guest)
@@ -188,11 +190,13 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
}
isb();
+ /* Write out the host state if it's in the registers */
if (vcpu->arch.flags & KVM_ARM64_FP_HOST) {
__fpsimd_save_state(vcpu->arch.host_fpsimd_state);
vcpu->arch.flags &= ~KVM_ARM64_FP_HOST;
}
+ /* Restore the guest state */
if (sve_guest)
__hyp_sve_restore_guest(vcpu);
else
--
2.30.2
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