From: Marc Zyngier Date: Mon, 21 Jul 2025 10:19:51 +0000 (+0100) Subject: KVM: arm64: Make RAS registers UNDEF when RAS isn't advertised X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d9c5c2320156ba4c7ac79db2ea98f4445a18c2e7;p=thirdparty%2Flinux.git KVM: arm64: Make RAS registers UNDEF when RAS isn't advertised We currently always expose FEAT_RAS when available on the host. As we are about to make this feature selectable from userspace, check for it being present before emulating register accesses as RAZ/WI, and inject an UNDEF otherwise. Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20250721101955.535159-4-maz@kernel.org Signed-off-by: Oliver Upton --- diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 9d4fe892e8b4b..0baa1b6050e70 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2656,6 +2656,23 @@ static bool access_mdcr(struct kvm_vcpu *vcpu, return true; } +static bool access_ras(struct kvm_vcpu *vcpu, + struct sys_reg_params *p, + const struct sys_reg_desc *r) +{ + struct kvm *kvm = vcpu->kvm; + + switch(reg_to_encoding(r)) { + default: + if (!kvm_has_feat(kvm, ID_AA64PFR0_EL1, RAS, IMP)) { + kvm_inject_undefined(vcpu); + return false; + } + } + + return trap_raz_wi(vcpu, p, r); +} + /* * For historical (ahem ABI) reasons, KVM treated MIDR_EL1, REVIDR_EL1, and * AIDR_EL1 as "invariant" registers, meaning userspace cannot change them. @@ -3003,14 +3020,14 @@ static const struct sys_reg_desc sys_reg_descs[] = { { SYS_DESC(SYS_AFSR1_EL1), access_vm_reg, reset_unknown, AFSR1_EL1 }, { SYS_DESC(SYS_ESR_EL1), access_vm_reg, reset_unknown, ESR_EL1 }, - { SYS_DESC(SYS_ERRIDR_EL1), trap_raz_wi }, - { SYS_DESC(SYS_ERRSELR_EL1), trap_raz_wi }, - { SYS_DESC(SYS_ERXFR_EL1), trap_raz_wi }, - { SYS_DESC(SYS_ERXCTLR_EL1), trap_raz_wi }, - { SYS_DESC(SYS_ERXSTATUS_EL1), trap_raz_wi }, - { SYS_DESC(SYS_ERXADDR_EL1), trap_raz_wi }, - { SYS_DESC(SYS_ERXMISC0_EL1), trap_raz_wi }, - { SYS_DESC(SYS_ERXMISC1_EL1), trap_raz_wi }, + { SYS_DESC(SYS_ERRIDR_EL1), access_ras }, + { SYS_DESC(SYS_ERRSELR_EL1), access_ras }, + { SYS_DESC(SYS_ERXFR_EL1), access_ras }, + { SYS_DESC(SYS_ERXCTLR_EL1), access_ras }, + { SYS_DESC(SYS_ERXSTATUS_EL1), access_ras }, + { SYS_DESC(SYS_ERXADDR_EL1), access_ras }, + { SYS_DESC(SYS_ERXMISC0_EL1), access_ras }, + { SYS_DESC(SYS_ERXMISC1_EL1), access_ras }, MTE_REG(TFSR_EL1), MTE_REG(TFSRE0_EL1),