KVM: x86: Keep MSR_IA32_XSS unchanged for INIT

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>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a50baf4..b6d60c2 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11266,6 +11266,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
                vcpu->arch.msr_misc_features_enables = 0;
 
                vcpu->arch.xcr0 = XFEATURE_MASK_FP;
+               vcpu->arch.ia32_xss = 0;
        }
 
        /* All GPRs except RDX (handled below) are zeroed on RESET/INIT. */
@@ -11282,8 +11283,6 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
        cpuid_0x1 = kvm_find_cpuid_entry(vcpu, 1, 0);
        kvm_rdx_write(vcpu, cpuid_0x1 ? cpuid_0x1->eax : 0x600);
 
-       vcpu->arch.ia32_xss = 0;
-
        static_call(kvm_x86_vcpu_reset)(vcpu, init_event);
 
        kvm_set_rflags(vcpu, X86_EFLAGS_FIXED);