The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 05a9e065059e566f218f8778c4d17ee75db56c55 Mon Sep 17 00:00:00 2001 From: Like Xu likexu@tencent.com Date: Wed, 26 Jan 2022 17:22:26 +0000 Subject: [PATCH] KVM: x86: Sync the states size with the XCR0/IA32_XSS at, any time
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, existing 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") Cc: stable@vger.kernel.org Signed-off-by: Like Xu likexu@tencent.com Signed-off-by: Sean Christopherson seanjc@google.com Message-Id: 20220126172226.2298529-4-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 9c984eeed30c..5481d2259f02 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11266,8 +11266,8 @@ 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; + __kvm_set_xcr(vcpu, 0, XFEATURE_MASK_FP); + __kvm_set_msr(vcpu, MSR_IA32_XSS, 0, true); }
/* All GPRs except RDX (handled below) are zeroed on RESET/INIT. */