| Message ID | 20250304060647.2903469-3-pbonzini@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | KVM: x86: Introduce quirk KVM_X86_QUIRK_IGNORE_GUEST_PAT | expand |
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 35d03fcdb8e9..5abea6c73a38 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -9775,6 +9775,7 @@ 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.inapplicable_quirks = KVM_X86_CONDITIONAL_QUIRKS; > > rdmsrl_safe(MSR_EFER, &kvm_host.efer); > > @@ -12754,6 +12755,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) > kvm->arch.apic_bus_cycle_ns = APIC_BUS_CYCLE_NS_DEFAULT; > kvm->arch.guest_can_read_msr_platform_info = true; > kvm->arch.enable_pmu = enable_pmu; > + kvm->arch.disabled_quirks = kvm_caps.inapplicable_quirks; Should be kvm->arch.disabled_quirks |= kvm_caps.inapplicable_quirks; Otherwise, it may overwrite the disabled_quirks value set in vm_init hook. > > #if IS_ENABLED(CONFIG_HYPERV) > spin_lock_init(&kvm->arch.hv_root_tdp_lock);
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 7ebbedc566ff..a4f213d235dd 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -2420,6 +2420,9 @@ int memslot_rmap_alloc(struct kvm_memory_slot *slot, unsigned long npages); KVM_X86_QUIRK_SLOT_ZAP_ALL | \ KVM_X86_QUIRK_STUFF_FEATURE_MSRS) +#define KVM_X86_CONDITIONAL_QUIRKS \ + KVM_X86_QUIRK_CD_NW_CLEARED + /* * KVM previously used a u32 field in kvm_run to indicate the hypercall was * initiated from long mode. KVM now sets bit 0 to indicate long mode, but the diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index ebaa5a41db07..51cfef44b58d 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -5426,6 +5426,7 @@ static __init int svm_hardware_setup(void) */ allow_smaller_maxphyaddr = !npt_enabled; + kvm_caps.inapplicable_quirks &= ~KVM_X86_QUIRK_CD_NW_CLEARED; return 0; err: diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 35d03fcdb8e9..5abea6c73a38 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9775,6 +9775,7 @@ 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.inapplicable_quirks = KVM_X86_CONDITIONAL_QUIRKS; rdmsrl_safe(MSR_EFER, &kvm_host.efer); @@ -12754,6 +12755,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) kvm->arch.apic_bus_cycle_ns = APIC_BUS_CYCLE_NS_DEFAULT; kvm->arch.guest_can_read_msr_platform_info = true; kvm->arch.enable_pmu = enable_pmu; + kvm->arch.disabled_quirks = kvm_caps.inapplicable_quirks; #if IS_ENABLED(CONFIG_HYPERV) spin_lock_init(&kvm->arch.hv_root_tdp_lock); diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index 8ce6da98b5a2..221778792c3c 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -34,6 +34,7 @@ struct kvm_caps { u64 supported_xcr0; u64 supported_xss; u64 supported_perf_cap; + u64 inapplicable_quirks; }; struct kvm_host_values {
In some cases, the handling of quirks is split between platform-specific code and generic code, or it is done entirely in generic code, but the relevant bug does not trigger on some platforms; for example, this will be the case for "ignore guest PAT". Allow unaffected vendor modules to disable handling of a quirk for all VMs via a new entry in kvm_caps. Such quirks remain available in KVM_CAP_DISABLE_QUIRKS2, because that API tells userspace that KVM *knows* that some of its past behavior was bogus or just undesirable. In other words, it's plausible for userspace to refuse to run if a quirk is not listed by KVM_CAP_DISABLE_QUIRKS2, so preserve that and make it part of the API. As an example, mark KVM_X86_QUIRK_CD_NW_CLEARED as auto-disabled on Intel systems. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- arch/x86/include/asm/kvm_host.h | 3 +++ arch/x86/kvm/svm/svm.c | 1 + arch/x86/kvm/x86.c | 2 ++ arch/x86/kvm/x86.h | 1 + 4 files changed, 7 insertions(+)