From 5cb57a1aff7551bcb3b800d33141b06ef0ac178b Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 27 Aug 2024 16:25:11 +0100 Subject: [PATCH] KVM: arm64: Zero ID_AA64PFR0_EL1.GIC when no GICv3 is presented to the guest In order to be consistent, we shouldn't advertise a GICv3 when none is actually usable by the guest. Wipe the feature when these conditions apply, and allow the field to be written from userspace. This now allows us to rewrite the kvm_has_gicv3 helper() in terms of kvm_has_feat(), given that it is always evaluated at runtime. Reviewed-by: Oliver Upton Link: https://lore.kernel.org/r/20240827152517.3909653-6-maz@kernel.org Signed-off-by: Marc Zyngier --- arch/arm64/kvm/sys_regs.c | 8 +++++++- arch/arm64/kvm/vgic/vgic.h | 4 +--- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index bc2d54da38279..e9d8e916e3af4 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2365,7 +2365,6 @@ static const struct sys_reg_desc sys_reg_descs[] = { ID_AA64PFR0_EL1_MPAM | ID_AA64PFR0_EL1_SVE | ID_AA64PFR0_EL1_RAS | - ID_AA64PFR0_EL1_GIC | ID_AA64PFR0_EL1_AdvSIMD | ID_AA64PFR0_EL1_FP), }, ID_SANITISED(ID_AA64PFR1_EL1), @@ -4634,6 +4633,13 @@ int kvm_finalize_sys_regs(struct kvm_vcpu *vcpu) guard(mutex)(&kvm->arch.config_lock); + if (!(static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif) && + irqchip_in_kernel(kvm) && + kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3)) { + kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64PFR0_EL1)] &= ~ID_AA64PFR0_EL1_GIC_MASK; + kvm->arch.id_regs[IDREG_IDX(SYS_ID_PFR1_EL1)] &= ~ID_PFR1_EL1_GIC_MASK; + } + if (vcpu_has_nv(vcpu)) { int ret = kvm_init_nv_sysregs(kvm); if (ret) diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h index c72c38b442340..f2486b4d9f956 100644 --- a/arch/arm64/kvm/vgic/vgic.h +++ b/arch/arm64/kvm/vgic/vgic.h @@ -350,9 +350,7 @@ void vcpu_set_ich_hcr(struct kvm_vcpu *vcpu); static inline bool kvm_has_gicv3(struct kvm *kvm) { - return (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif) && - irqchip_in_kernel(kvm) && - kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3); + return kvm_has_feat(kvm, ID_AA64PFR0_EL1, GIC, IMP); } #endif -- 2.39.5