From: Sean Christopherson <seanjc@xxxxxxxxxx> Reject KVM_CAP_X86_DISABLE_EXITS if userspace attempts to disable MWAIT exits and KVM previously reported (via KVM_CHECK_EXTENSION) that MWAIT is not allowed in guest, e.g. because it's not supported or the CPU doesn't have an aways-running APIC timer. Fixes: 4d5422cea3b6 ("KVM: X86: Provide a capability to disable MWAIT intercepts") Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> Signed-off-by: Kechen Lu <kechenl@xxxxxxxxxx> --- arch/x86/kvm/x86.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9a77b55142c6..60caa3fd40e5 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4326,6 +4326,16 @@ static inline bool kvm_can_mwait_in_guest(void) boot_cpu_has(X86_FEATURE_ARAT); } +static u64 kvm_get_allowed_disable_exits(void) +{ + u64 r = KVM_X86_DISABLE_VALID_EXITS; + + if (!kvm_can_mwait_in_guest()) + r &= ~KVM_X86_DISABLE_EXITS_MWAIT; + + return r; +} + static int kvm_ioctl_get_supported_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 __user *cpuid_arg) { @@ -4448,10 +4458,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = KVM_CLOCK_VALID_FLAGS; break; case KVM_CAP_X86_DISABLE_EXITS: - r |= KVM_X86_DISABLE_EXITS_HLT | KVM_X86_DISABLE_EXITS_PAUSE | - KVM_X86_DISABLE_EXITS_CSTATE; - if(kvm_can_mwait_in_guest()) - r |= KVM_X86_DISABLE_EXITS_MWAIT; + r |= kvm_get_allowed_disable_exits(); break; case KVM_CAP_X86_SMM: if (!IS_ENABLED(CONFIG_KVM_SMM)) @@ -6224,15 +6231,14 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, break; case KVM_CAP_X86_DISABLE_EXITS: r = -EINVAL; - if (cap->args[0] & ~KVM_X86_DISABLE_VALID_EXITS) + if (cap->args[0] & ~kvm_get_allowed_disable_exits()) break; mutex_lock(&kvm->lock); if (kvm->created_vcpus) goto disable_exits_unlock; - if ((cap->args[0] & KVM_X86_DISABLE_EXITS_MWAIT) && - kvm_can_mwait_in_guest()) + if (cap->args[0] & KVM_X86_DISABLE_EXITS_MWAIT) kvm->arch.mwait_in_guest = true; if (cap->args[0] & KVM_X86_DISABLE_EXITS_HLT) kvm->arch.hlt_in_guest = true; -- 2.34.1