On Fri, Aug 7, 2020 at 1:47 AM Chenyi Qiang <chenyi.qiang@xxxxxxxxx> wrote: > > PKS MSR passes through guest directly. Configure the MSR to match the > L0/L1 settings so that nested VM runs PKS properly. > > Signed-off-by: Chenyi Qiang <chenyi.qiang@xxxxxxxxx> > --- > arch/x86/kvm/vmx/nested.c | 32 ++++++++++++++++++++++++++++++++ > arch/x86/kvm/vmx/vmcs12.c | 2 ++ > arch/x86/kvm/vmx/vmcs12.h | 6 +++++- > arch/x86/kvm/vmx/vmx.c | 10 ++++++++++ > arch/x86/kvm/vmx/vmx.h | 1 + > 5 files changed, 50 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c > index df2c2e733549..1f9823d21ecd 100644 > --- a/arch/x86/kvm/vmx/nested.c > +++ b/arch/x86/kvm/vmx/nested.c > @@ -647,6 +647,12 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu, > MSR_IA32_PRED_CMD, > MSR_TYPE_W); > > + if (!msr_write_intercepted_l01(vcpu, MSR_IA32_PKRS)) > + nested_vmx_disable_intercept_for_msr( > + msr_bitmap_l1, msr_bitmap_l0, > + MSR_IA32_PKRS, > + MSR_TYPE_R | MSR_TYPE_W); What if L1 intercepts only *reads* of MSR_IA32_PKRS? > kvm_vcpu_unmap(vcpu, &to_vmx(vcpu)->nested.msr_bitmap_map, false); > > return true; > @@ -2509,6 +2519,11 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, > if (kvm_mpx_supported() && (!vmx->nested.nested_run_pending || > !(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS))) > vmcs_write64(GUEST_BNDCFGS, vmx->nested.vmcs01_guest_bndcfgs); > + > + if (kvm_cpu_cap_has(X86_FEATURE_PKS) && Is the above check superfluous? I would assume that the L1 guest can't set VM_ENTRY_LOAD_IA32_PKRS unless this is true. > + (!vmx->nested.nested_run_pending || > + !(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_PKRS))) > + vmcs_write64(GUEST_IA32_PKRS, vmx->nested.vmcs01_guest_pkrs); This doesn't seem right to me. On the target of a live migration, with L2 active at the time the snapshot was taken (i.e., vmx->nested.nested_run_pending=0), it looks like we're going to try to overwrite the current L2 PKRS value with L1's PKRS value (except that in this situation, vmx->nested.vmcs01_guest_pkrs should actually be 0). Am I missing something? > vmx_set_rflags(vcpu, vmcs12->guest_rflags); > > /* EXCEPTION_BITMAP and CR0_GUEST_HOST_MASK should basically be the > @@ -3916,6 +3943,8 @@ static void sync_vmcs02_to_vmcs12_rare(struct kvm_vcpu *vcpu, > vmcs_readl(GUEST_PENDING_DBG_EXCEPTIONS); > if (kvm_mpx_supported()) > vmcs12->guest_bndcfgs = vmcs_read64(GUEST_BNDCFGS); > + if (kvm_cpu_cap_has(X86_FEATURE_PKS)) Shouldn't we be checking to see if the *virtual* CPU supports PKS before writing anything into vmcs12->guest_ia32_pkrs? > + vmcs12->guest_ia32_pkrs = vmcs_read64(GUEST_IA32_PKRS); > > vmx->nested.need_sync_vmcs02_to_vmcs12_rare = false; > }
