3.16.57-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: KarimAllah Ahmed <[email protected]> commit 28c1c9fabf48d6ad596273a11c46e0d0da3e14cd upstream. 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. [dwmw2: The bit in kvm_cpuid_7_0_edx_x86_features can be unconditional] Signed-off-by: KarimAllah Ahmed <[email protected]> Signed-off-by: David Woodhouse <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Paolo Bonzini <[email protected]> Reviewed-by: Darren Kenny <[email protected]> Reviewed-by: Jim Mattson <[email protected]> Reviewed-by: Konrad Rzeszutek Wilk <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Jun Nakajima <[email protected]> Cc: [email protected] Cc: Dave Hansen <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Asit Mallick <[email protected]> Cc: Arjan Van De Ven <[email protected]> Cc: Greg KH <[email protected]> Cc: Dan Williams <[email protected]> Cc: Tim Chen <[email protected]> Cc: Ashok Raj <[email protected]> Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: David Woodhouse <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> [bwh: Backported to 3.16: - Add mapping of the relevant CPUID word - Adjust context] Signed-off-by: Ben Hutchings <[email protected]> --- arch/x86/kvm/cpuid.c | 11 +++++++++-- arch/x86/kvm/cpuid.h | 8 ++++++++ arch/x86/kvm/vmx.c | 15 +++++++++++++++ arch/x86/kvm/x86.c | 3 ++- 4 files changed, 34 insertions(+), 3 deletions(-) --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -316,6 +316,10 @@ static inline int __do_cpuid_ent(struct F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) | F(ADX) | F(SMAP); + /* 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(); @@ -387,11 +391,14 @@ static inline int __do_cpuid_ent(struct cpuid_mask(&entry->ebx, 9); // TSC_ADJUST is emulated entry->ebx |= F(TSC_ADJUST); - } else + entry->edx &= kvm_cpuid_7_0_edx_x86_features; + cpuid_mask(&entry->edx, 10); + } else { entry->ebx = 0; + entry->edx = 0; + } entry->eax = 0; entry->ecx = 0; - entry->edx = 0; break; } case 9: --- a/arch/x86/kvm/cpuid.h +++ b/arch/x86/kvm/cpuid.h @@ -115,5 +115,13 @@ static inline bool guest_cpuid_has_ibpb( 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)); +} + #endif --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -432,6 +432,8 @@ struct vcpu_vmx { u64 msr_guest_kernel_gs_base; #endif + u64 arch_capabilities; + u32 vm_entry_controls_shadow; u32 vm_exit_controls_shadow; /* @@ -2522,6 +2524,12 @@ static int vmx_get_msr(struct kvm_vcpu * case MSR_IA32_TSC: msr_info->data = guest_read_tsc(); 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; @@ -2641,6 +2649,11 @@ static int vmx_set_msr(struct kvm_vcpu * 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)) @@ -4584,6 +4597,8 @@ static int vmx_vcpu_setup(struct vcpu_vm ++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); --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -893,7 +893,8 @@ static u32 msrs_to_save[] = { MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR, #endif MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA, - MSR_IA32_FEATURE_CONTROL, MSR_IA32_BNDCFGS + MSR_IA32_FEATURE_CONTROL, MSR_IA32_BNDCFGS, + MSR_IA32_ARCH_CAPABILITIES }; static unsigned num_msrs_to_save;
