pve-kernel-lowlatency-qoup/patches/kernel/0012-KVM-x86-Emulate-MSR_IA32_ARCH_CAPABILITIES-on-AMD-ho.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <sean.j.christopherson@intel.com>
Date: Thu, 7 Mar 2019 15:43:02 -0800
Subject: [PATCH] KVM: x86: Emulate MSR_IA32_ARCH_CAPABILITIES on AMD hosts

BugLink: https://bugs.launchpad.net/bugs/1823060

commit 0cf9135b773bf32fba9dd8e6699c1b331ee4b749 upstream.

The CPUID flag ARCH_CAPABILITIES is unconditioinally exposed to host
userspace for all x86 hosts, i.e. KVM advertises ARCH_CAPABILITIES
regardless of hardware support under the pretense that KVM fully
emulates MSR_IA32_ARCH_CAPABILITIES.  Unfortunately, only VMX hosts
handle accesses to MSR_IA32_ARCH_CAPABILITIES (despite KVM_GET_MSRS
also reporting MSR_IA32_ARCH_CAPABILITIES for all hosts).

Move the MSR_IA32_ARCH_CAPABILITIES handling to common x86 code so
that it's emulated on AMD hosts.

Fixes: 1eaafe91a0df4 ("kvm: x86: IA32_ARCH_CAPABILITIES is always supported")
Cc: stable@vger.kernel.org
Reported-by: Xiaoyao Li <xiaoyao.li@linux.intel.com>
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>

(back ported from commit 0cf9135b773bf32fba9dd8e6699c1b331ee4b749)
Backported-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kvm/vmx.c              | 14 --------------
 arch/x86/kvm/x86.c              | 12 ++++++++++++
 3 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index e76012ca0ddc..fa57f78dff2d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -508,6 +508,7 @@ struct kvm_vcpu_arch {
 	bool tpr_access_reporting;
 	u64 ia32_xss;
 	u64 microcode_version;
+	u64 arch_capabilities;
 
 	/*
 	 * Paging state of the vcpu
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 38e50b40db5a..1911ec5e26c1 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -750,7 +750,6 @@ struct vcpu_vmx {
 	u64 		      msr_guest_kernel_gs_base;
 #endif
 
-	u64 		      arch_capabilities;
 	u64 		      spec_ctrl;
 
 	u32 vm_entry_controls_shadow;
@@ -3477,12 +3476,6 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 
 		msr_info->data = to_vmx(vcpu)->spec_ctrl;
 		break;
-	case MSR_IA32_ARCH_CAPABILITIES:
-		if (!msr_info->host_initiated &&
-		    !guest_cpuid_has(vcpu, X86_FEATURE_ARCH_CAPABILITIES))
-			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;
@@ -3644,11 +3637,6 @@ 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))
@@ -5906,8 +5894,6 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx)
 		++vmx->nmsrs;
 	}
 
-	vmx->arch_capabilities = kvm_get_arch_capabilities();
-
 	vm_exit_controls_init(vmx, vmcs_config.vmexit_ctrl);
 
 	/* 22.2.1, 20.8.1 */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3d3d6d6548c3..92a8b20b7103 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2247,6 +2247,11 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		if (msr_info->host_initiated)
 			vcpu->arch.microcode_version = data;
 		break;
+	case MSR_IA32_ARCH_CAPABILITIES:
+		if (!msr_info->host_initiated)
+			return 1;
+		vcpu->arch.arch_capabilities = data;
+		break;
 	case MSR_EFER:
 		return set_efer(vcpu, data);
 	case MSR_K7_HWCR:
@@ -2543,6 +2548,12 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_IA32_UCODE_REV:
 		msr_info->data = vcpu->arch.microcode_version;
 		break;
+	case MSR_IA32_ARCH_CAPABILITIES:
+		if (!msr_info->host_initiated &&
+		    !guest_cpuid_has(vcpu, X86_FEATURE_ARCH_CAPABILITIES))
+			return 1;
+		msr_info->data = vcpu->arch.arch_capabilities;
+		break;
 	case MSR_IA32_TSC:
 		msr_info->data = kvm_scale_tsc(vcpu, rdtsc()) + vcpu->arch.tsc_offset;
 		break;
@@ -7951,6 +7962,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
 
 int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
 {
+	vcpu->arch.arch_capabilities = kvm_get_arch_capabilities();
 	vcpu->arch.msr_platform_info = MSR_PLATFORM_INFO_CPUID_FAULT;
 	kvm_vcpu_mtrr_init(vcpu);
 	vcpu_load(vcpu);