diff mbox series

[v3,3/3] i386: Add support for SUCCOR feature

Message ID 20230906205308.50334-4-john.allen@amd.com (mailing list archive)
State New, archived
Headers show
Series Fix MCE handling on AMD hosts | expand

Commit Message

John Allen Sept. 6, 2023, 8:53 p.m. UTC 
Add cpuid bit definition for the SUCCOR feature. This cpuid bit is required to
be exposed to guests to allow them to handle machine check exceptions on AMD
hosts.

Reported-by: William Roche <william.roche@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: John Allen <john.allen@amd.com>
----
v2:
  - Add "succor" feature word.
  - Add case to kvm_arch_get_supported_cpuid for the SUCCOR feature.
---
 target/i386/cpu.c     | 18 +++++++++++++++++-
 target/i386/cpu.h     |  4 ++++
 target/i386/kvm/kvm.c |  2 ++
 3 files changed, 23 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 00f913b638..d90d3a9489 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1029,6 +1029,22 @@  FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         .tcg_features = TCG_APM_FEATURES,
         .unmigratable_flags = CPUID_APM_INVTSC,
     },
+    [FEAT_8000_0007_EBX] = {
+        .type = CPUID_FEATURE_WORD,
+        .feat_names = {
+            NULL, "succor", NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+        },
+        .cpuid = { .eax = 0x80000007, .reg = R_EBX, },
+        .tcg_features = 0,
+        .unmigratable_flags = 0,
+    },
     [FEAT_8000_0008_EBX] = {
         .type = CPUID_FEATURE_WORD,
         .feat_names = {
@@ -6554,7 +6570,7 @@  void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         break;
     case 0x80000007:
         *eax = 0;
-        *ebx = 0;
+        *ebx = env->features[FEAT_8000_0007_EBX];
         *ecx = 0;
         *edx = env->features[FEAT_8000_0007_EDX];
         break;
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index a6000e93bd..f5afc5e4fd 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -598,6 +598,7 @@  typedef enum FeatureWord {
     FEAT_7_1_EAX,       /* CPUID[EAX=7,ECX=1].EAX */
     FEAT_8000_0001_EDX, /* CPUID[8000_0001].EDX */
     FEAT_8000_0001_ECX, /* CPUID[8000_0001].ECX */
+    FEAT_8000_0007_EBX, /* CPUID[8000_0007].EBX */
     FEAT_8000_0007_EDX, /* CPUID[8000_0007].EDX */
     FEAT_8000_0008_EBX, /* CPUID[8000_0008].EBX */
     FEAT_8000_0021_EAX, /* CPUID[8000_0021].EAX */
@@ -942,6 +943,9 @@  uint64_t x86_cpu_get_supported_feature_word(FeatureWord w,
 /* Packets which contain IP payload have LIP values */
 #define CPUID_14_0_ECX_LIP              (1U << 31)
 
+/* RAS Features */
+#define CPUID_8000_0007_EBX_SUCCOR      (1U << 1)
+
 /* CLZERO instruction */
 #define CPUID_8000_0008_EBX_CLZERO      (1U << 0)
 /* Always save/restore FP error pointers */
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 4d42d3ed4c..0255863421 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -477,6 +477,8 @@  uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function,
          */
         cpuid_1_edx = kvm_arch_get_supported_cpuid(s, 1, 0, R_EDX);
         ret |= cpuid_1_edx & CPUID_EXT2_AMD_ALIASES;
+    } else if (function == 0x80000007 && reg == R_EBX) {
+        ret |= CPUID_8000_0007_EBX_SUCCOR;
     } else if (function == KVM_CPUID_FEATURES && reg == R_EAX) {
         /* kvm_pv_unhalt is reported by GET_SUPPORTED_CPUID, but it can't
          * be enabled without the in-kernel irqchip