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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Xiaoyao Li <xiaoyao.li@intel.com>,
        Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>
Subject: [PATCH 5.15 039/171] KVM: x86: Keep MSR_IA32_XSS unchanged for INIT
Date:   Mon, 31 Jan 2022 11:55:04 +0100
Message-Id: <20220131105231.341874862@linuxfoundation.org>
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From: Xiaoyao Li <xiaoyao.li@intel.com>

commit be4f3b3f82271c3193ce200a996dc70682c8e622 upstream.

It has been corrected from SDM version 075 that MSR_IA32_XSS is reset to
zero on Power up and Reset but keeps unchanged on INIT.

Fixes: a554d207dc46 ("KVM: X86: Processor States following Reset or INIT")
Cc: stable@vger.kernel.org
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220126172226.2298529-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/kvm/x86.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10990,6 +10990,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcp
 		vcpu->arch.msr_misc_features_enables = 0;
 
 		vcpu->arch.xcr0 = XFEATURE_MASK_FP;
+		vcpu->arch.ia32_xss = 0;
 	}
 
 	memset(vcpu->arch.regs, 0, sizeof(vcpu->arch.regs));
@@ -11008,8 +11009,6 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcp
 		eax = 0x600;
 	kvm_rdx_write(vcpu, eax);
 
-	vcpu->arch.ia32_xss = 0;
-
 	static_call(kvm_x86_vcpu_reset)(vcpu, init_event);
 
 	kvm_set_rflags(vcpu, X86_EFLAGS_FIXED);