From: Like Xu <likexu@xxxxxxxxxxx> XCR0 is reset to 1 by RESET but not INIT and IA32_XSS is zeroed by both RESET and INIT. The kvm_set_msr_common()'s handling of MSR_IA32_XSS also needs to update kvm_update_cpuid_runtime(). In the above cases, the size in bytes of the XSAVE area containing all states enabled by XCR0 or (XCRO | IA32_XSS) needs to be updated. For simplicity and consistency, legacy helpers are used to write values and call kvm_update_cpuid_runtime(), and it's not exactly a fast path. Fixes: a554d207dc46 ("KVM: X86: Processor States following Reset or INIT") Signed-off-by: Like Xu <likexu@xxxxxxxxxxx> --- v1 -> v2 Changelog: - Strongly prefer that use the helpers to write the values; (Sean) - Postpone IA32_XSS test cases once non-zero values are supported; (Paolo) - User space may call SET_CPUID2 after kvm_vcpu_reset(init_event=false); (Paolo) arch/x86/kvm/x86.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 55518b7d3b96..22d4b1d15e94 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11256,7 +11256,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) vcpu->arch.msr_misc_features_enables = 0; - vcpu->arch.xcr0 = XFEATURE_MASK_FP; + __kvm_set_xcr(vcpu, 0, XFEATURE_MASK_FP); } /* All GPRs except RDX (handled below) are zeroed on RESET/INIT. */ @@ -11273,7 +11273,7 @@ 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; + __kvm_set_msr(vcpu, MSR_IA32_XSS, 0, true); static_call(kvm_x86_vcpu_reset)(vcpu, init_event); -- 2.33.1