KVM: x86: Introduce supported_quirks to block disabling quirks

Introduce supported_quirks in kvm_caps to store platform-specific force-enabled
quirks.

No functional changes intended.

Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Message-ID: <20250224070832.31394-1-yan.y.zhao@intel.com>
[Remove unsupported quirks at KVM_ENABLE_CAP time. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 93168a4..920b36c 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4790,7 +4790,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
                r = enable_pmu ? KVM_CAP_PMU_VALID_MASK : 0;
                break;
        case KVM_CAP_DISABLE_QUIRKS2:
-               r = KVM_X86_VALID_QUIRKS;
+               r = kvm_caps.supported_quirks;
                break;
        case KVM_CAP_X86_NOTIFY_VMEXIT:
                r = kvm_caps.has_notify_vmexit;
@@ -6529,11 +6529,11 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
        switch (cap->cap) {
        case KVM_CAP_DISABLE_QUIRKS2:
                r = -EINVAL;
-               if (cap->args[0] & ~KVM_X86_VALID_QUIRKS)
+               if (cap->args[0] & ~kvm_caps.supported_quirks)
                        break;
                fallthrough;
        case KVM_CAP_DISABLE_QUIRKS:
-               kvm->arch.disabled_quirks |= cap->args[0];
+               kvm->arch.disabled_quirks |= cap->args[0] & kvm_caps.supported_quirks;
                r = 0;
                break;
        case KVM_CAP_SPLIT_IRQCHIP: {
@@ -9783,6 +9783,7 @@ int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
                kvm_host.xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
                kvm_caps.supported_xcr0 = kvm_host.xcr0 & KVM_SUPPORTED_XCR0;
        }
+       kvm_caps.supported_quirks = KVM_X86_VALID_QUIRKS;
        kvm_caps.inapplicable_quirks = KVM_X86_CONDITIONAL_QUIRKS;
 
        rdmsrl_safe(MSR_EFER, &kvm_host.efer);
@@ -12734,7 +12735,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
        /* Decided by the vendor code for other VM types.  */
        kvm->arch.pre_fault_allowed =
                type == KVM_X86_DEFAULT_VM || type == KVM_X86_SW_PROTECTED_VM;
-       kvm->arch.disabled_quirks = kvm_caps.inapplicable_quirks;
+       kvm->arch.disabled_quirks = kvm_caps.inapplicable_quirks & kvm_caps.supported_quirks;
 
        ret = kvm_page_track_init(kvm);
        if (ret)

diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 2217787..287dac3 100644 (file)
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -34,6 +34,8 @@ struct kvm_caps {
        u64 supported_xcr0;
        u64 supported_xss;
        u64 supported_perf_cap;
+
+       u64 supported_quirks;
        u64 inapplicable_quirks;
 };