Sean Christopherson <[email protected]> writes: > +Vitaly > > On Thu, Feb 25, 2021, Yang Weijiang wrote: >> These fields are rarely updated by L1 QEMU/KVM, sync them when L1 is trying >> to >> read/write them and after they're changed. If CET guest entry-load bit is not >> set by L1 guest, migrate them to L2 manaully. >> >> Suggested-by: Sean Christopherson <[email protected]> >> Signed-off-by: Yang Weijiang <[email protected]> >> >> change in v2: >> - Per Sean's review feedback, change CET guest states as rarely-updated >> fields. >> And also migrate L1's CET states to L2 if the entry-load bit is not set. >> - Opportunistically removed one blank line. >> --- >> arch/x86/kvm/cpuid.c | 1 - >> arch/x86/kvm/vmx/nested.c | 29 +++++++++++++++++++++++++++++ >> arch/x86/kvm/vmx/vmx.h | 3 +++ >> 3 files changed, 32 insertions(+), 1 deletion(-) >> >> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c >> index 46087bca9418..afc97122c05c 100644 >> --- a/arch/x86/kvm/cpuid.c >> +++ b/arch/x86/kvm/cpuid.c >> @@ -143,7 +143,6 @@ void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu) >> } >> vcpu->arch.guest_supported_xss = >> (((u64)best->edx << 32) | best->ecx) & supported_xss; >> - >> } else { >> vcpu->arch.guest_supported_xss = 0; >> } >> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c >> index 9728efd529a1..1703b8874fad 100644 >> --- a/arch/x86/kvm/vmx/nested.c >> +++ b/arch/x86/kvm/vmx/nested.c >> @@ -2516,6 +2516,12 @@ static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, >> struct vmcs12 *vmcs12) >> vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.guest.nr); >> >> set_cr4_guest_host_mask(vmx); >> + >> + if (kvm_cet_supported()) { > > This needs to be conditioned on CET coming from vmcs12, it's on the loading of > host state on VM-Exit that is unconditional (if CET is supported). > > if (kvm_cet_supported() && vmx->nested.nested_run_pending && > (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_CET_STATE)) { > > I also assume these should be guarded by one of the eVMCS fields, though a > quick > search of the public docs didn't provide a hit on the CET fields. > > Vitaly, any idea if these will be GUEST_GRP2 or something else? >
The latest published TLFS I see is 6.0b and it doesn't list anything CET related in eVMCS v1.0 :-( So I agree with Paolo: we just need to adjust EVMCS1_UNSUPPORTED_VMENTRY_CTRL/ EVMCS1_UNSUPPORTED_VMEXIT_CTRL for now and enable it separately later. >> + vmcs_writel(GUEST_SSP, vmcs12->guest_ssp); >> + vmcs_writel(GUEST_S_CET, vmcs12->guest_s_cet); >> + vmcs_writel(GUEST_INTR_SSP_TABLE, vmcs12->guest_ssp_tbl); >> + } >> } > -- Vitaly
