On 06/02/2018 18:29, David Woodhouse wrote: > From: KarimAllah Ahmed <karahmed@xxxxxxxxx> > > Intel processors use MSR_IA32_ARCH_CAPABILITIES MSR to indicate RDCL_NO > (bit 0) and IBRS_ALL (bit 1). This is a read-only MSR. By default the > contents will come directly from the hardware, but user-space can still > override it. Uhm, taking contents from the hardware is wrong (guess why---live migration). I'll send a revert of those two lines. Paolo > [dwmw2: The bit in kvm_cpuid_7_0_edx_x86_features can be unconditional] > > Signed-off-by: KarimAllah Ahmed <karahmed@xxxxxxxxx> > Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx> > Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> > Reviewed-by: Darren Kenny <darren.kenny@xxxxxxxxxx> > Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx> > Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> > Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx> > Cc: Jun Nakajima <jun.nakajima@xxxxxxxxx> > Cc: kvm@xxxxxxxxxxxxxxx > Cc: Dave Hansen <dave.hansen@xxxxxxxxx> > Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Cc: Andy Lutomirski <luto@xxxxxxxxxx> > Cc: Asit Mallick <asit.k.mallick@xxxxxxxxx> > Cc: Arjan Van De Ven <arjan.van.de.ven@xxxxxxxxx> > Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> > Cc: Dan Williams <dan.j.williams@xxxxxxxxx> > Cc: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> > Cc: Ashok Raj <ashok.raj@xxxxxxxxx> > Link: https://lkml.kernel.org/r/1517522386-18410-4-git-send-email-karahmed@xxxxxxxxx > > (cherry picked from commit 28c1c9fabf48d6ad596273a11c46e0d0da3e14cd) > Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx> > --- > arch/x86/kvm/cpuid.c | 8 +++++++- > arch/x86/kvm/cpuid.h | 8 ++++++++ > arch/x86/kvm/vmx.c | 15 +++++++++++++++ > arch/x86/kvm/x86.c | 1 + > 4 files changed, 31 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index 6f24483..9c6493f 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -380,6 +380,10 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, > /* cpuid 7.0.ecx*/ > const u32 kvm_cpuid_7_0_ecx_x86_features = F(PKU) | 0 /*OSPKE*/; > > + /* cpuid 7.0.edx*/ > + const u32 kvm_cpuid_7_0_edx_x86_features = > + F(ARCH_CAPABILITIES); > + > /* all calls to cpuid_count() should be made on the same cpu */ > get_cpu(); > > @@ -462,12 +466,14 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, > /* PKU is not yet implemented for shadow paging. */ > if (!tdp_enabled || !boot_cpu_has(X86_FEATURE_OSPKE)) > entry->ecx &= ~F(PKU); > + entry->edx &= kvm_cpuid_7_0_edx_x86_features; > + cpuid_mask(&entry->edx, CPUID_7_EDX); > } else { > entry->ebx = 0; > entry->ecx = 0; > + entry->edx = 0; > } > entry->eax = 0; > - entry->edx = 0; > break; > } > case 9: > diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h > index ec4f9dc..8719997 100644 > --- a/arch/x86/kvm/cpuid.h > +++ b/arch/x86/kvm/cpuid.h > @@ -171,6 +171,14 @@ static inline bool guest_cpuid_has_ibpb(struct kvm_vcpu *vcpu) > return best && (best->edx & bit(X86_FEATURE_SPEC_CTRL)); > } > > +static inline bool guest_cpuid_has_arch_capabilities(struct kvm_vcpu *vcpu) > +{ > + struct kvm_cpuid_entry2 *best; > + > + best = kvm_find_cpuid_entry(vcpu, 7, 0); > + return best && (best->edx & bit(X86_FEATURE_ARCH_CAPABILITIES)); > +} > + > > /* > * NRIPS is provided through cpuidfn 0x8000000a.edx bit 3 > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index dd6c831..92bf61f 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -551,6 +551,8 @@ struct vcpu_vmx { > u64 msr_guest_kernel_gs_base; > #endif > > + u64 arch_capabilities; > + > u32 vm_entry_controls_shadow; > u32 vm_exit_controls_shadow; > /* > @@ -2979,6 +2981,12 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > case MSR_IA32_TSC: > msr_info->data = guest_read_tsc(vcpu); > break; > + case MSR_IA32_ARCH_CAPABILITIES: > + if (!msr_info->host_initiated && > + !guest_cpuid_has_arch_capabilities(vcpu)) > + return 1; > + msr_info->data = to_vmx(vcpu)->arch_capabilities; > + break; > case MSR_IA32_SYSENTER_CS: > msr_info->data = vmcs_read32(GUEST_SYSENTER_CS); > break; > @@ -3110,6 +3118,11 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > vmx_disable_intercept_for_msr(vmx->vmcs01.msr_bitmap, MSR_IA32_PRED_CMD, > MSR_TYPE_W); > break; > + case MSR_IA32_ARCH_CAPABILITIES: > + if (!msr_info->host_initiated) > + return 1; > + vmx->arch_capabilities = data; > + break; > case MSR_IA32_CR_PAT: > if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) { > if (!kvm_mtrr_valid(vcpu, MSR_IA32_CR_PAT, data)) > @@ -5200,6 +5213,8 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx) > ++vmx->nmsrs; > } > > + if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES)) > + rdmsrl(MSR_IA32_ARCH_CAPABILITIES, vmx->arch_capabilities); > > vm_exit_controls_init(vmx, vmcs_config.vmexit_ctrl); > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index e023ef9..94d1573 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -975,6 +975,7 @@ static u32 msrs_to_save[] = { > #endif > MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA, > MSR_IA32_FEATURE_CONTROL, MSR_IA32_BNDCFGS, MSR_TSC_AUX, > + MSR_IA32_ARCH_CAPABILITIES > }; > > static unsigned num_msrs_to_save; >