diff --git a/target-i386-check-for-availability-of-MSR_IA32_UCODE.patch b/target-i386-check-for-availability-of-MSR_IA32_UCODE.patch new file mode 100644 index 0000000..377226a --- /dev/null +++ b/target-i386-check-for-availability-of-MSR_IA32_UCODE.patch @@ -0,0 +1,58 @@ +From 0633e7684b4f4da858a3739d68cb57a1d49bdf01 Mon Sep 17 00:00:00 2001 +From: Paolo Bonzini +Date: Tue, 11 Feb 2020 18:55:16 +0100 +Subject: [PATCH] target/i386: check for availability of MSR_IA32_UCODE_REV as + an emulated MSR + +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 +Message-id: <20200211175516.10716-1-pbonzini@redhat.com> +Signed-off-by: Paolo Bonzini +--- + target/i386/kvm.c | 7 +++++-- + 1 file changed, 5 insertions(+), 2 deletions(-) + +diff --git a/target/i386/kvm.c b/target/i386/kvm.c +index 7437f86130..e49a2d2585 100644 +--- a/target/i386/kvm.c ++++ b/target/i386/kvm.c +@@ -99,6 +99,7 @@ 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 bool has_msr_vmx_procbased_ctls2; + + static uint32_t has_architectural_pmu_version; +@@ -1985,6 +1986,9 @@ 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; + case MSR_IA32_VMX_PROCBASED_CTLS2: + has_msr_vmx_procbased_ctls2 = true; + break; +@@ -2628,8 +2632,7 @@ 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); + } + +-- +2.27.0 +