From 8f39b0c9523630efeb451e2298cf64b88cd2ac81 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Mon, 17 Feb 2020 16:23:13 +0000
Subject: [PATCH 3/9] target/i386: kvm: initialize microcode revision from KVM
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RH-Author: Paolo Bonzini <pbonzini@redhat.com>
Message-id: <20200217162316.2464-4-pbonzini@redhat.com>
Patchwork-id: 93897
O-Subject: [RHEL-AV-8.2.0 qemu-kvm PATCH 3/6] target/i386: kvm: initialize microcode revision from KVM
Bugzilla: 1791648
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
RH-Acked-by: Maxim Levitsky <mlevitsk@redhat.com>
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

KVM can return the host microcode revision as a feature MSR.
Use it as the default value for -cpu host.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1579544504-3616-4-git-send-email-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 32c87d70ff55b96741f08c35108935cac6f40fe4)
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 target/i386/cpu.c | 4 ++++
 target/i386/kvm.c | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index e505d3e..5ac843d 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -6323,6 +6323,10 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
                        &cpu->mwait.ecx, &cpu->mwait.edx);
             env->features[FEAT_1_ECX] |= CPUID_EXT_MONITOR;
         }
+        if (kvm_enabled() && cpu->ucode_rev == 0) {
+            cpu->ucode_rev = kvm_arch_get_supported_msr_feature(kvm_state,
+                                                                MSR_IA32_UCODE_REV);
+        }
     }
 
     if (cpu->ucode_rev == 0) {
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index f41605b..6c61aef 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -2696,6 +2696,11 @@ 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)) {
+        kvm_msr_entry_add(cpu, MSR_IA32_UCODE_REV, cpu->ucode_rev);
+    }
+
     /*
      * Older kernels do not include VMX MSRs in KVM_GET_MSR_INDEX_LIST, but
      * all kernels with MSR features should have them.
-- 
1.8.3.1