Re: [PATCH] KVM: SVM: fix trashing of MSR_TSC_AUX

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On Thu, Jul 07, 2016 at 03:16:21PM +0200, Paolo Bonzini wrote:
> Eduardo is the one to answer, but usually we add features to QEMU 
> before the processors are released (typically as soon as KVM supports 
> them).  So with a new enough QEMU this in theory should not be 
> necessary.
> 
> Adding a new feature that's not in a CPU model and that's not 
> associated to new state is really trivial:

Cool.

Btw, how about something like this?

Specifically, I'd like to test RAS features on the new upcoming AMD
Zen CPU and I've defined one from the stuff we know so far from kernel
patches.

The "filter=off" thing I've added in case I want to disable
x86_cpu_filter_features() but it works just fine without it when I boot
with -cpu Zen. So I can remove it too.

Would something like that be acceptable?

We can continue improving on this as features become known and even
implement some functionality in qemu/kvm as time allows.

---
From: Borislav Petkov <bp@xxxxxxx>
Date: Tue, 5 Jul 2016 16:12:18 +0200
Subject: [PATCH] Zen emu: first working version

Boot with "-c Zen,filter=off" to disable CPUID bits filtering.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
 target-i386/cpu.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 target-i386/cpu.h |  7 +++++++
 2 files changed, 66 insertions(+), 1 deletion(-)

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 3bd3cfc3ad16..cc9c97457387 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -307,6 +307,17 @@ static const char *cpuid_6_feature_name[] = {
     NULL, NULL, NULL, NULL,
 };
 
+static const char *smca_feature_name[] = {
+    "overflow_recov", "succor", NULL, "smca",
+    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,
+};
+
 #define I486_FEATURES (CPUID_FP87 | CPUID_VME | CPUID_PSE)
 #define PENTIUM_FEATURES (I486_FEATURES | CPUID_DE | CPUID_TSC | \
           CPUID_MSR | CPUID_MCE | CPUID_CX8 | CPUID_MMX | CPUID_APIC)
@@ -449,6 +460,11 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         .cpuid_eax = 6, .cpuid_reg = R_EAX,
         .tcg_features = TCG_6_EAX_FEATURES,
     },
+    [FEAT_8000_0007_EBX] = {
+	.feat_names = smca_feature_name,
+	.cpuid_eax = 0x80000007,
+	.cpuid_reg = R_EBX,
+    },
 };
 
 typedef struct X86RegisterInfo32 {
@@ -1449,6 +1465,44 @@ static X86CPUDefinition builtin_x86_defs[] = {
         .xlevel = 0x8000001A,
         .model_id = "AMD Opteron 63xx class CPU",
     },
+    {
+        .name = "Zen",
+        .level = 0xd,
+        .vendor = CPUID_VENDOR_AMD,
+        .family = 23,
+        .model = 0,
+        .stepping = 0,
+        .features[FEAT_1_EDX] =
+            CPUID_VME | CPUID_SSE2 | CPUID_SSE | CPUID_FXSR | CPUID_MMX |
+            CPUID_CLFLUSH | CPUID_PSE36 | CPUID_PAT | CPUID_CMOV | CPUID_MCA |
+            CPUID_PGE | CPUID_MTRR | CPUID_SEP | CPUID_APIC | CPUID_CX8 |
+            CPUID_MCE | CPUID_PAE | CPUID_MSR | CPUID_TSC | CPUID_PSE |
+            CPUID_DE | CPUID_FP87,
+        .features[FEAT_1_ECX] =
+            CPUID_EXT_F16C | CPUID_EXT_AVX | CPUID_EXT_XSAVE |
+            CPUID_EXT_AES | CPUID_EXT_POPCNT | CPUID_EXT_SSE42 |
+            CPUID_EXT_SSE41 | CPUID_EXT_CX16 | CPUID_EXT_FMA |
+            CPUID_EXT_SSSE3 | CPUID_EXT_PCLMULQDQ | CPUID_EXT_SSE3,
+        .features[FEAT_8000_0001_EDX] =
+            CPUID_EXT2_LM | CPUID_EXT2_RDTSCP |
+            CPUID_EXT2_PDPE1GB | CPUID_EXT2_FXSR | CPUID_EXT2_MMX |
+            CPUID_EXT2_NX | CPUID_EXT2_PSE36 | CPUID_EXT2_PAT |
+            CPUID_EXT2_CMOV | CPUID_EXT2_MCA | CPUID_EXT2_PGE |
+            CPUID_EXT2_MTRR | CPUID_EXT2_SYSCALL | CPUID_EXT2_APIC |
+            CPUID_EXT2_CX8 | CPUID_EXT2_MCE | CPUID_EXT2_PAE | CPUID_EXT2_MSR |
+            CPUID_EXT2_TSC | CPUID_EXT2_PSE | CPUID_EXT2_DE | CPUID_EXT2_FPU,
+        .features[FEAT_8000_0001_ECX] =
+            CPUID_EXT3_TBM | CPUID_EXT3_FMA4 | CPUID_EXT3_XOP |
+            CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE |
+            CPUID_EXT3_SSE4A | CPUID_EXT3_ABM | CPUID_EXT3_SVM |
+            CPUID_EXT3_LAHF_LM,
+        /* no xsaveopt! */
+        .features[FEAT_8000_0007_EBX] =
+            CPUID_OVERFLOW_RECOV | CPUID_SUCCOR | CPUID_SMCA,
+        .xlevel = 0x8000001A,
+        .model_id = "AMD Zen CPU",
+    },
+
 };
 
 typedef struct PropValue {
@@ -2118,6 +2172,9 @@ static int x86_cpu_filter_features(X86CPU *cpu)
     FeatureWord w;
     int rv = 0;
 
+    if (!cpu->filter_cpuid)
+        return 0;
+
     for (w = 0; w < FEATURE_WORDS; w++) {
         uint32_t host_feat =
             x86_cpu_get_supported_feature_word(w, cpu->migratable);
@@ -2596,7 +2653,7 @@ 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;
@@ -3256,6 +3313,7 @@ static Property x86_cpu_properties[] = {
     DEFINE_PROP_BOOL("hv-stimer", X86CPU, hyperv_stimer, false),
     DEFINE_PROP_BOOL("check", X86CPU, check_cpuid, true),
     DEFINE_PROP_BOOL("enforce", X86CPU, enforce_cpuid, false),
+    DEFINE_PROP_BOOL("filter", X86CPU, filter_cpuid, false),
     DEFINE_PROP_BOOL("kvm", X86CPU, expose_kvm, true),
     DEFINE_PROP_UINT32("level", X86CPU, env.cpuid_level, 0),
     DEFINE_PROP_UINT32("xlevel", X86CPU, env.cpuid_xlevel, 0),
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 474b0b937d71..258c1b261cd2 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -443,6 +443,7 @@ typedef enum FeatureWord {
     FEAT_SVM,           /* CPUID[8000_000A].EDX */
     FEAT_XSAVE,         /* CPUID[EAX=0xd,ECX=1].EAX */
     FEAT_6_EAX,         /* CPUID[6].EAX */
+    FEAT_8000_0007_EBX, /* CPUID[8000_0007].EBX */
     FEATURE_WORDS,
 } FeatureWord;
 
@@ -620,6 +621,11 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
 #define CPUID_APM_INVTSC       (1U << 8)
 
 #define CPUID_VENDOR_SZ      12
+/* CPUID[0x80000007].EBX flags: */
+#define CPUID_OVERFLOW_RECOV   (1U << 0) /* MCA overflow recovery support */
+#define CPUID_SUCCOR	       (1U << 1) /* Uncorrectable error containment and recovery */
+#define CPUID_SMCA	       (1U << 3) /* Scalable MCA */
+
 
 #define CPUID_VENDOR_INTEL_1 0x756e6547 /* "Genu" */
 #define CPUID_VENDOR_INTEL_2 0x49656e69 /* "ineI" */
@@ -1160,6 +1166,7 @@ struct X86CPU {
     bool hyperv_stimer;
     bool check_cpuid;
     bool enforce_cpuid;
+    bool filter_cpuid;
     bool expose_kvm;
     bool migratable;
     bool host_features;
-- 
2.7.3

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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