Messages in this thread | | | Date | Mon, 15 Nov 2021 23:39:21 +0800 | Subject | Re: [PATCH 04/11] KVM: x86: Disable MCE related stuff for TDX | From | Xiaoyao Li <> |
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On 11/13/2021 1:01 AM, Sean Christopherson wrote: > On Fri, Nov 12, 2021, Xiaoyao Li wrote: >> From: Sean Christopherson <sean.j.christopherson@intel.com> >> >> MCE is not supported for TDX VM and KVM cannot inject #MC to TDX VM. >> >> Introduce kvm_guest_mce_disallowed() which actually reports the MCE >> availability based on vm_type. And use it to guard all the MCE related >> CAPs and IOCTLs. >> >> Note: KVM_X86_GET_MCE_CAP_SUPPORTED is KVM scope so that what it reports >> may not match the behavior of specific VM (e.g., here for TDX VM). The >> same for KVM_CAP_MCE when queried from /dev/kvm. To qeuery the precise >> KVM_CAP_MCE of the VM, it should use VM's fd. >> >> [ Xiaoyao: Guard MCE related CAPs ] >> >> Co-developed-by: Kai Huang <kai.huang@linux.intel.com> >> Signed-off-by: Kai Huang <kai.huang@linux.intel.com> >> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> >> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> >> --- >> arch/x86/kvm/x86.c | 10 ++++++++++ >> arch/x86/kvm/x86.h | 5 +++++ >> 2 files changed, 15 insertions(+) >> >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index b02088343d80..2b21c5169f32 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -4150,6 +4150,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) >> break; >> case KVM_CAP_MCE: >> r = KVM_MAX_MCE_BANKS; >> + if (kvm) >> + r = kvm_guest_mce_disallowed(kvm) ? 0 : r; > > r = KVM_MAX_MCE_BANKS; > if (kvm && kvm_guest_mce_disallowed(kvm)) > r = 0; > > or > > r = (kvm && kvm_guest_mce_disallowed(kvm)) ? 0 : KVM_MAX_MCE_BANKS;
I will use this one in next submission.
>> break; >> case KVM_CAP_XCRS: >> r = boot_cpu_has(X86_FEATURE_XSAVE); >> @@ -5155,6 +5157,10 @@ long kvm_arch_vcpu_ioctl(struct file *filp, >> case KVM_X86_SETUP_MCE: { >> u64 mcg_cap; >> >> + r = EINVAL; >> + if (kvm_guest_mce_disallowed(vcpu->kvm)) >> + goto out; >> + >> r = -EFAULT; >> if (copy_from_user(&mcg_cap, argp, sizeof(mcg_cap))) >> goto out; >> @@ -5164,6 +5170,10 @@ long kvm_arch_vcpu_ioctl(struct file *filp, >> case KVM_X86_SET_MCE: { >> struct kvm_x86_mce mce; >> >> + r = EINVAL; >> + if (kvm_guest_mce_disallowed(vcpu->kvm)) >> + goto out; >> + >> r = -EFAULT; >> if (copy_from_user(&mce, argp, sizeof(mce))) >> goto out; >> diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h >> index a2813892740d..69c60297bef2 100644 >> --- a/arch/x86/kvm/x86.h >> +++ b/arch/x86/kvm/x86.h >> @@ -441,6 +441,11 @@ static __always_inline bool kvm_irq_injection_disallowed(struct kvm_vcpu *vcpu) >> return vcpu->kvm->arch.vm_type == KVM_X86_TDX_VM; >> } >> >> +static __always_inline bool kvm_guest_mce_disallowed(struct kvm *kvm) > > The "guest" part is potentially confusing and incosistent with e.g. > kvm_irq_injection_disallowed. And given the current ridiculous spec, CR4.MCE=1 > is _required_, so saying "mce disallowed" is arguably wrong from that perspective. > > kvm_mce_injection_disallowed() would be more appropriate.
Good advice, I'll rename to it.
>> +{ >> + return kvm->arch.vm_type == KVM_X86_TDX_VM; >> +} >> + >> void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu); >> void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu); >> int kvm_spec_ctrl_test_value(u64 value); >> -- >> 2.27.0 >>
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