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