From: Oliver Upton Date: Thu, 18 Sep 2025 16:46:31 +0000 (-0700) Subject: KVM: arm64: nv: Treat AMO as 1 when at EL2 and {E2H,TGE} = {1, 0} X-Git-Tag: v6.18-rc1~95^2~5^2~2^2~1 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ff37a41db8b47834b747b3bb427825fc75bc86a7;p=thirdparty%2Flinux.git KVM: arm64: nv: Treat AMO as 1 when at EL2 and {E2H,TGE} = {1, 0} SErrors are not deliverable at EL2 when the effective value of HCR_EL2.{TGE,AMO} = {0, 0}. This is bothersome to deal with in nested as we need to use auxiliary pending state to track the pending vSError since HCR_EL2.VSE has no mechanism for honoring the guest HCR. On top of that, we have no way of making that auxiliary pending state visible in ISR_EL1. A defect against the architecture now allows an implementation to treat HCR_EL2.AMO as 1 when HCR_EL2.{E2H,TGE} = {1, 0}. Let's do exactly that, meaning SErrors are always deliverable at EL2 for the typical E2H=RES1 VM. Signed-off-by: Oliver Upton Signed-off-by: Marc Zyngier --- diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index fa8a08a1ccd5c..64ce3fec73ee9 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -220,6 +220,20 @@ static inline bool vcpu_el2_tge_is_set(const struct kvm_vcpu *vcpu) static inline bool vcpu_el2_amo_is_set(const struct kvm_vcpu *vcpu) { + /* + * DDI0487L.b Known Issue D22105 + * + * When executing at EL2 and HCR_EL2.{E2H,TGE} = {1, 0} it is + * IMPLEMENTATION DEFINED whether the effective value of HCR_EL2.AMO + * is the value programmed or 1. + * + * Make the implementation choice of treating the effective value as 1 as + * we cannot subsequently catch changes to TGE or AMO that would + * otherwise lead to the SError becoming deliverable. + */ + if (vcpu_is_el2(vcpu) && vcpu_el2_e2h_is_set(vcpu) && !vcpu_el2_tge_is_set(vcpu)) + return true; + return ctxt_sys_reg(&vcpu->arch.ctxt, HCR_EL2) & HCR_AMO; }