[1/6] KVM: VMX: Remove unneeded check for X86_FEATURE_XSAVE

Message ID	20191009004142.225377-1-aaronlewis@google.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=YPTB=YC=vger.kernel.org=kvm-owner@kernel.org> Date: Tue, 8 Oct 2019 17:41:37 -0700 Message-Id: <20191009004142.225377-1-aaronlewis@google.com> Mime-Version: 1.0 Subject: [Patch 1/6] KVM: VMX: Remove unneeded check for X86_FEATURE_XSAVE From: Aaron Lewis <aaronlewis@google.com> To: Babu Moger <Babu.Moger@amd.com>, Yang Weijiang <weijiang.yang@intel.com>, Sebastian Andrzej Siewior <bigeasy@linutronix.de>, kvm@vger.kernel.org Cc: Paolo Bonzini <pbonzini@redhat.com>, Aaron Lewis <aaronlewis@google.com>, Jim Mattson <jmattson@google.com> Content-Type: text/plain; charset="UTF-8" Sender: kvm-owner@vger.kernel.org Precedence: bulk
Series	[1/6] KVM: VMX: Remove unneeded check for X86_FEATURE_XSAVE \| expand [1/6] KVM: VMX: Remove unneeded check for X86_FEATURE_XSAVE [2/6] KVM: VMX: Use wrmsr for switching between guest and host IA32_XSS [3/6] kvm: svm: Add support for XSAVES on AMD [4/6] kvm: svm: Enumerate XSAVES in guest CPUID when it is available to the guest [5/6] kvm: x86: Add IA32_XSS to the emulated_msrs list [6/6] kvm: tests: Add test to verify MSR_IA32_XSS

Message ID

20191009004142.225377-1-aaronlewis@google.com (mailing list archive)

State

New, archived

Headers

Date: Tue,  8 Oct 2019 17:41:37 -0700
Message-Id: <20191009004142.225377-1-aaronlewis@google.com>
Mime-Version: 1.0
Subject: [Patch 1/6] KVM: VMX: Remove unneeded check for X86_FEATURE_XSAVE
From: Aaron Lewis <aaronlewis@google.com>
To: Babu Moger <Babu.Moger@amd.com>,
        Yang Weijiang <weijiang.yang@intel.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
        Aaron Lewis <aaronlewis@google.com>,
        Jim Mattson <jmattson@google.com>
Content-Type: text/plain; charset="UTF-8"
Sender: kvm-owner@vger.kernel.org
Precedence: bulk

Series

[1/6] KVM: VMX: Remove unneeded check for X86_FEATURE_XSAVE | expand

Commit Message

Aaron Lewis Oct. 9, 2019, 12:41 a.m. UTC

The SDM says that IA32_XSS is supported "If(CPUID.(0DH, 1):EAX.[3] = 1",
so only the X86_FEATURE_XSAVES check is necessary.

Fixes: 4d763b168e9c5 ("KVM: VMX: check CPUID before allowing read/write of IA32_XSS")
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
---
 arch/x86/kvm/vmx/vmx.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index e7970a2e8eae..409e9a7323f1 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1823,8 +1823,7 @@  static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_IA32_XSS:
 		if (!vmx_xsaves_supported() ||
 		    (!msr_info->host_initiated &&
-		     !(guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
-		       guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))))
+		     !guest_cpuid_has(vcpu, X86_FEATURE_XSAVES)))
 			return 1;
 		msr_info->data = vcpu->arch.ia32_xss;
 		break;
@@ -2066,8 +2065,7 @@  static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_IA32_XSS:
 		if (!vmx_xsaves_supported() ||
 		    (!msr_info->host_initiated &&
-		     !(guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
-		       guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))))
+		     !guest_cpuid_has(vcpu, X86_FEATURE_XSAVES)))
 			return 1;
 		/*
 		 * The only supported bit as of Skylake is bit 8, but