This is a note to let you know that I've just added the patch titled
KVM/VMX: Emulate MSR_IA32_ARCH_CAPABILITIES
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-vmx-emulate-msr_ia32_arch_capabilities.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 28c1c9fabf48d6ad596273a11c46e0d0da3e14cd Mon Sep 17 00:00:00 2001
From: KarimAllah Ahmed <karahmed@xxxxxxxxx>
Date: Thu, 1 Feb 2018 22:59:44 +0100
Subject: KVM/VMX: Emulate MSR_IA32_ARCH_CAPABILITIES
From: KarimAllah Ahmed <karahmed@xxxxxxxxx>
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 <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
Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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(-)
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -380,6 +380,10 @@ static inline int __do_cpuid_ent(struct
/* 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
/* 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:
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -171,6 +171,14 @@ 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));
+}
+
/*
* NRIPS is provided through cpuidfn 0x8000000a.edx bit 3
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -550,6 +550,8 @@ struct vcpu_vmx {
u64 msr_guest_kernel_gs_base;
#endif
+ u64 arch_capabilities;
+
u32 vm_entry_controls_shadow;
u32 vm_exit_controls_shadow;
/*
@@ -2981,6 +2983,12 @@ static int vmx_get_msr(struct kvm_vcpu *
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;
@@ -3112,6 +3120,11 @@ 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))
@@ -5202,6 +5215,8 @@ 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
@@ -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;
Patches currently in stable-queue which might be from karahmed@xxxxxxxxx are
queue-4.9/kvm-vmx-allow-direct-access-to-msr_ia32_spec_ctrl.patch
queue-4.9/kvm-x86-add-ibpb-support.patch
queue-4.9/kvm-svm-allow-direct-access-to-msr_ia32_spec_ctrl.patch
queue-4.9/kvm-vmx-emulate-msr_ia32_arch_capabilities.patch