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Subject[PATCH 5.16 058/200] KVM: x86: Sync the states size with the XCR0/IA32_XSS at, any time
Date
From: Like Xu <likexu@tencent.com>

commit 05a9e065059e566f218f8778c4d17ee75db56c55 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/x86.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11065,8 +11065,8 @@ 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;
+ __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. */

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