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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>,
	Jim Mattson <jmattson@google.com>,
	Aaron Lewis <aaronlewis@google.com>
Subject: [PATCH v2 1/5] KVM: VMX: Remove unneeded check for X86_FEATURE_XSAVE
Date: Fri, 11 Oct 2019 12:40:28 -0700	[thread overview]
Message-ID: <20191011194032.240572-2-aaronlewis@google.com> (raw)
In-Reply-To: <20191011194032.240572-1-aaronlewis@google.com>

Volume 4 of 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
-- 
2.23.0.700.g56cf767bdb-goog


  reply	other threads:[~2019-10-11 19:41 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-11 19:40 [PATCH v2 0/5] Add support for XSAVES on AMD and unify it with Intel Aaron Lewis
2019-10-11 19:40 ` Aaron Lewis [this message]
2019-10-11 19:40 ` [PATCH v2 2/5] KVM: VMX: Use wrmsr for switching between guest and host IA32_XSS Aaron Lewis
2019-10-12  0:18   ` Sean Christopherson
2019-10-12 17:36     ` Jim Mattson
2019-10-14 19:05       ` Sean Christopherson
2019-10-14 21:01         ` Jim Mattson
2019-10-14 23:55           ` Sean Christopherson
2019-10-11 19:40 ` [PATCH v2 3/5] kvm: svm: Add support for XSAVES on AMD Aaron Lewis
2019-10-11 19:40 ` [PATCH v2 4/5] kvm: x86: Add IA32_XSS to the emulated_msrs list Aaron Lewis
2019-10-11 19:40 ` [PATCH v2 5/5] kvm: tests: Add test to verify MSR_IA32_XSS Aaron Lewis

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