[PATCH] KVM: x86: Keep MSR_IA32_XSS unchanged for INIT

From: Xiaoyao Li
Date: Tue Jan 25 2022 - 22:47:56 EST


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")
Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
---
arch/x86/kvm/x86.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 55518b7d3b96..c0727939684e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11257,6 +11257,7 @@ 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. */
@@ -11273,8 +11274,6 @@ 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);
--
2.27.0