kernel/SOURCES/1043-KVM-x86-Advertise-that-the-SMM_CTL-MSR-is-not-suppor.patch

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From 35b7cde8ddf1c374c533ec0de2958d2cd74e587d Mon Sep 17 00:00:00 2001
From: Jim Mattson <jmattson@google.com>
Date: Fri, 7 Oct 2022 15:16:44 -0700
Subject: [PATCH 29/36] KVM: x86: Advertise that the SMM_CTL MSR is not
supported
CPUID.80000021H:EAX[bit 9] indicates that the SMM_CTL MSR (0xc0010116) is
not supported. This defeature can be advertised by KVM_GET_SUPPORTED_CPUID
regardless of whether or not the host enumerates it; currently it will be
included only if the host enumerates at least leaf 8000001DH, due to a
preexisting bug in QEMU that KVM has to work around (commit f751d8eac176,
"KVM: x86: work around QEMU issue with synthetic CPUID leaves", 2022-04-29).
Signed-off-by: Jim Mattson <jmattson@google.com>
Message-Id: <20221007221644.138355-1-jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 74bee0cad8dcd8ddec5e763c369239fc5990676a)
Signed-off-by: Mridula Shastry <mridula.c.shastry@oracle.com>
Reviewed-by: Todd Vierling <todd.vierling@oracle.com>
---
arch/x86/kvm/cpuid.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 6e3f385a3648..3726861ae52a 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1180,8 +1180,12 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
* Other defined bits are for MSRs that KVM does not expose:
* EAX 3 SPCL, SMM page configuration lock
* EAX 13 PCMSR, Prefetch control MSR
+ *
+ * KVM doesn't support SMM_CTL.
+ * EAX 9 SMM_CTL MSR is not supported
*/
entry->eax &= BIT(0) | BIT(2) | BIT(6);
+ entry->eax |= BIT(9);
if (static_cpu_has(X86_FEATURE_LFENCE_RDTSC))
entry->eax |= BIT(2);
if (!static_cpu_has_bug(X86_BUG_NULL_SEG))
--
2.39.3