From 36f998de853cfad60508dfdfb41c9c40a2245f19 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Sun, 12 Jan 2025 16:50:29 +0000 Subject: [PATCH] KVM: arm64: nv: Apply RESx settings to sysreg reset values While we have sanitisation in place for the guest sysregs, we lack that sanitisation out of reset. So some of the fields could be evaluated and not reflect their RESx status, which sounds like a very bad idea. Apply the RESx masks to the the sysreg file in two situations: - when going via a reset of the sysregs - after having computed the RESx masks Having this separate reset phase from the actual reset handling is a bit grotty, but we need to apply this after the ID registers are final. Tested-by: Joey Gouly Reviewed-by: Joey Gouly Link: https://lore.kernel.org/r/20250112165029.1181056-3-maz@kernel.org Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_nested.h | 2 +- arch/arm64/kvm/nested.c | 9 +++++++-- arch/arm64/kvm/sys_regs.c | 5 ++++- 3 files changed, 12 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h index 233e655227164..f616e25e204f1 100644 --- a/arch/arm64/include/asm/kvm_nested.h +++ b/arch/arm64/include/asm/kvm_nested.h @@ -186,7 +186,7 @@ static inline bool kvm_supported_tlbi_s1e2_op(struct kvm_vcpu *vpcu, u32 instr) return true; } -int kvm_init_nv_sysregs(struct kvm *kvm); +int kvm_init_nv_sysregs(struct kvm_vcpu *vcpu); #ifdef CONFIG_ARM64_PTR_AUTH bool kvm_auth_eretax(struct kvm_vcpu *vcpu, u64 *elr); diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index 9b36218b48def..dd6480cf90ea5 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -963,14 +963,15 @@ static __always_inline void set_sysreg_masks(struct kvm *kvm, int sr, u64 res0, kvm->arch.sysreg_masks->mask[i].res1 = res1; } -int kvm_init_nv_sysregs(struct kvm *kvm) +int kvm_init_nv_sysregs(struct kvm_vcpu *vcpu) { + struct kvm *kvm = vcpu->kvm; u64 res0, res1; lockdep_assert_held(&kvm->arch.config_lock); if (kvm->arch.sysreg_masks) - return 0; + goto out; kvm->arch.sysreg_masks = kzalloc(sizeof(*(kvm->arch.sysreg_masks)), GFP_KERNEL_ACCOUNT); @@ -1271,6 +1272,10 @@ int kvm_init_nv_sysregs(struct kvm *kvm) res0 |= MDCR_EL2_EnSTEPOP; set_sysreg_masks(kvm, MDCR_EL2, res0, res1); +out: + for (enum vcpu_sysreg sr = __SANITISED_REG_START__; sr < NR_SYS_REGS; sr++) + (void)__vcpu_sys_reg(vcpu, sr); + return 0; } diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 83c6b4a07ef56..8671d46f53e59 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -4396,6 +4396,9 @@ void kvm_reset_sys_regs(struct kvm_vcpu *vcpu) reset_vcpu_ftr_id_reg(vcpu, r); else r->reset(vcpu, r); + + if (r->reg >= __SANITISED_REG_START__ && r->reg < NR_SYS_REGS) + (void)__vcpu_sys_reg(vcpu, r->reg); } set_bit(KVM_ARCH_FLAG_ID_REGS_INITIALIZED, &kvm->arch.flags); @@ -4999,7 +5002,7 @@ int kvm_finalize_sys_regs(struct kvm_vcpu *vcpu) } if (vcpu_has_nv(vcpu)) { - int ret = kvm_init_nv_sysregs(kvm); + int ret = kvm_init_nv_sysregs(vcpu); if (ret) return ret; } -- 2.49.0