Re: [PATCH 4/4] KVM: arm64: Check HCR_EL2 instead of shadow copy to swap PtrAuth registers
From: Mark Rutland <mark.rutland@arm.com>
Date: 2020-06-15 10:25:42
Also in:
kvm, kvmarm
On Mon, Jun 15, 2020 at 09:19:54AM +0100, Marc Zyngier wrote:
When save/restoring PtrAuth registers between host and guest, it is pretty useless to fetch the in-memory state, while we have the right state in the HCR_EL2 system register. Use that instead. Signed-off-by: Marc Zyngier <maz@kernel.org>
It took me a while to spot that we switched the guest/host hcr_el2 value in the __activate_traps() and __deactivate_traps() paths, but given that this is only called in the __kvm_vcpu_run_*() paths called between those, I agree this is sound. Given that: Acked-by: Mark Rutland <mark.rutland@arm.com> Mark.
quoted hunk ↗ jump to hunk
--- arch/arm64/include/asm/kvm_ptrauth.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/arch/arm64/include/asm/kvm_ptrauth.h b/arch/arm64/include/asm/kvm_ptrauth.h index 6301813dcace..f1830173fa9e 100644 --- a/arch/arm64/include/asm/kvm_ptrauth.h +++ b/arch/arm64/include/asm/kvm_ptrauth.h@@ -74,7 +74,7 @@ alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF b 1001f alternative_else_nop_endif 1000: - ldr \reg1, [\g_ctxt, #(VCPU_HCR_EL2 - VCPU_CONTEXT)] + mrs \reg1, hcr_el2 and \reg1, \reg1, #(HCR_API | HCR_APK) cbz \reg1, 1001f add \reg1, \g_ctxt, #CPU_APIAKEYLO_EL1@@ -90,7 +90,7 @@ alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF b 2001f alternative_else_nop_endif 2000: - ldr \reg1, [\g_ctxt, #(VCPU_HCR_EL2 - VCPU_CONTEXT)] + mrs \reg1, hcr_el2 and \reg1, \reg1, #(HCR_API | HCR_APK) cbz \reg1, 2001f add \reg1, \g_ctxt, #CPU_APIAKEYLO_EL1-- 2.27.0 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
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