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target/i386: check for availability of MSR_IA32_UCODE_REV as an emulated MSR

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Even though MSR_IA32_UCODE_REV has been available long before Linux 5.6,
which added it to the emulated MSR list, a bug caused the microcode
version to revert to 0x100000000 on INIT.  As a result, processors other
than the bootstrap processor would not see the host microcode revision;
some Windows version complain loudly about this and crash with a
fairly explicit MICROCODE REVISION MISMATCH error.

[If running 5.6 prereleases, the kernel fix "KVM: x86: do not reset
 microcode version on INIT or RESET" should also be applied.]

Reported-by: Alex Williamson <alex.williamson@redhat.com>
Message-id: <20200211175516.10716-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2020-02-11 18:55:16 +01:00
parent 9028c75c9d
commit 6702514814
1 changed files with 5 additions and 2 deletions
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7
target/i386/kvm.c
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@ -105,6 +105,7 @@ static bool has_msr_smi_count;
static bool has_msr_arch_capabs;
static bool has_msr_core_capabs;
static bool has_msr_vmx_vmfunc;
static bool has_msr_ucode_rev;
static uint32_t has_architectural_pmu_version;
static uint32_t num_architectural_pmu_gp_counters;
@ -2056,6 +2057,9 @@ static int kvm_get_supported_msrs(KVMState *s)
case MSR_IA32_VMX_VMFUNC:
has_msr_vmx_vmfunc = true;
break;
case MSR_IA32_UCODE_REV:
has_msr_ucode_rev = true;
break;
}
}
}
@ -2696,8 +2700,7 @@ static void kvm_init_msrs(X86CPU *cpu)
env->features[FEAT_CORE_CAPABILITY]);
}
if (kvm_arch_get_supported_msr_feature(kvm_state,
MSR_IA32_UCODE_REV)) {
if (has_msr_ucode_rev) {
kvm_msr_entry_add(cpu, MSR_IA32_UCODE_REV, cpu->ucode_rev);
}