[Qemu-devel] [Patch V2 1/2] x86, mce: Basic support to add LMCE support to QEMU

[Ashok Raj]

This patch adds basic enumeration, control msr's required to support
Local Machine Check Exception Support (LMCE).

- Added Local Machine Check definitions, changed MCG_CAP
- Added support for IA32_FEATURE_CONTROL.
- When delivering MCE to guest, we deliver to just a single CPU
  when guest OS has opted in to Local delivery.

Signed-off-by: Ashok Raj <address@hidden>
Tested-by: Gong Chen <address@hidden>
---
Resending with proper commit message for second patch

 target-i386/cpu.c |  8 ++++++++
 target-i386/cpu.h |  8 ++++++--
 target-i386/kvm.c | 38 +++++++++++++++++++++++++++++++-------
 3 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 11e5e39..167669a 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -2737,6 +2737,13 @@ static void mce_init(X86CPU *cpu)
     }
 }
 
+static void feature_control_init(X86CPU *cpu)
+{
+       CPUX86State *cenv = &cpu->env;
+
+       cenv->msr_ia32_feature_control = ((1<<20) | (1<<0));
+}
+
 #ifndef CONFIG_USER_ONLY
 static void x86_cpu_apic_create(X86CPU *cpu, Error **errp)
 {
@@ -2858,6 +2865,7 @@ static void x86_cpu_realizefn(DeviceState *dev, Error 
**errp)
 #endif
 
     mce_init(cpu);
+    feature_control_init(cpu);
 
 #ifndef CONFIG_USER_ONLY
     if (tcg_enabled()) {
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 84edfd0..a567d7a 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -282,8 +282,9 @@
 
 #define MCG_CTL_P       (1ULL<<8)   /* MCG_CAP register available */
 #define MCG_SER_P       (1ULL<<24) /* MCA recovery/new status bits */
+#define MCG_LMCE_P     (1ULL<<27) /* Local Machine Check Supported */
 
-#define MCE_CAP_DEF     (MCG_CTL_P|MCG_SER_P)
+#define MCE_CAP_DEF     (MCG_CTL_P|MCG_SER_P|MCG_LMCE_P)
 #define MCE_BANKS_DEF   10
 
 #define MCG_CAP_BANKS_MASK 0xff
@@ -291,6 +292,7 @@
 #define MCG_STATUS_RIPV (1ULL<<0)   /* restart ip valid */
 #define MCG_STATUS_EIPV (1ULL<<1)   /* ip points to correct instruction */
 #define MCG_STATUS_MCIP (1ULL<<2)   /* machine check in progress */
+#define MCG_STATUS_LMCE (1ULL<<3)   /* Local MCE signaled */
 
 #define MCI_STATUS_VAL   (1ULL<<63)  /* valid error */
 #define MCI_STATUS_OVER  (1ULL<<62)  /* previous errors lost */
@@ -333,6 +335,7 @@
 #define MSR_MCG_CAP                     0x179
 #define MSR_MCG_STATUS                  0x17a
 #define MSR_MCG_CTL                     0x17b
+#define MSR_MCG_EXT_CTL                        0x4d0
 
 #define MSR_P6_EVNTSEL0                 0x186
 
@@ -892,7 +895,6 @@ typedef struct CPUX86State {
 
     uint64_t mcg_status;
     uint64_t msr_ia32_misc_enable;
-    uint64_t msr_ia32_feature_control;
 
     uint64_t msr_fixed_ctr_ctrl;
     uint64_t msr_global_ctrl;
@@ -977,8 +979,10 @@ typedef struct CPUX86State {
     int64_t tsc_khz;
     void *kvm_xsave_buf;
 
+    uint64_t msr_ia32_feature_control;
     uint64_t mcg_cap;
     uint64_t mcg_ctl;
+    uint64_t mcg_ext_ctl;
     uint64_t mce_banks[MCE_BANKS_DEF*4];
 
     uint64_t tsc_aux;
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 6dc9846..c61fe1f 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -72,6 +72,7 @@ static bool has_msr_tsc_aux;
 static bool has_msr_tsc_adjust;
 static bool has_msr_tsc_deadline;
 static bool has_msr_feature_control;
+static bool has_msr_ext_mcg_ctl;
 static bool has_msr_async_pf_en;
 static bool has_msr_pv_eoi_en;
 static bool has_msr_misc_enable;
@@ -370,18 +371,30 @@ static void kvm_mce_inject(X86CPU *cpu, hwaddr paddr, int 
code)
     uint64_t status = MCI_STATUS_VAL | MCI_STATUS_UC | MCI_STATUS_EN |
                       MCI_STATUS_MISCV | MCI_STATUS_ADDRV | MCI_STATUS_S;
     uint64_t mcg_status = MCG_STATUS_MCIP;
+    int flags = 0;
+    CPUState *cs = CPU(cpu);
+
+    /*
+     * We need to read back the value of MSR_EXT_MCG_CTL that was set by the
+     * guest kernel back into Qemu
+     */
+    cpu_synchronize_state(cs);
+
+    flags = cpu_x86_support_mca_broadcast(env) ? MCE_INJECT_BROADCAST : 0;
 
     if (code == BUS_MCEERR_AR) {
-        status |= MCI_STATUS_AR | 0x134;
-        mcg_status |= MCG_STATUS_EIPV;
+       status |= MCI_STATUS_AR | 0x134;
+       mcg_status |= MCG_STATUS_EIPV;
+       if (env->mcg_ext_ctl & 0x1) {
+               mcg_status |= MCG_STATUS_LMCE;
+               flags = 0; /* No Broadcast when LMCE is opted by guest */
+       }
     } else {
         status |= 0xc0;
         mcg_status |= MCG_STATUS_RIPV;
     }
     cpu_x86_inject_mce(NULL, cpu, 9, status, mcg_status, paddr,
-                       (MCM_ADDR_PHYS << 6) | 0xc,
-                       cpu_x86_support_mca_broadcast(env) ?
-                       MCE_INJECT_BROADCAST : 0);
+                      (MCM_ADDR_PHYS << 6) | 0xc, flags);
 }
 
 static void hardware_memory_error(void)
@@ -808,10 +821,14 @@ int kvm_arch_init_vcpu(CPUState *cs)
 
     c = cpuid_find_entry(&cpuid_data.cpuid, 1, 0);
     if (c) {
-        has_msr_feature_control = !!(c->ecx & CPUID_EXT_VMX) ||
-                                  !!(c->ecx & CPUID_EXT_SMX);
+        has_msr_feature_control = !!((c->ecx & CPUID_EXT_VMX) ||
+                                  !!(c->ecx & CPUID_EXT_SMX) || 
+                                 !!(env->mcg_cap & MCG_LMCE_P));
     }
 
+    if (has_msr_feature_control && (env->mcg_cap & MCG_LMCE_P))
+        has_msr_ext_mcg_ctl = true;
+
     c = cpuid_find_entry(&cpuid_data.cpuid, 0x80000007, 0);
     if (c && (c->edx & 1<<8) && invtsc_mig_blocker == NULL) {
         /* for migration */
@@ -1557,6 +1574,7 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
 
         kvm_msr_entry_set(&msrs[n++], MSR_MCG_STATUS, env->mcg_status);
         kvm_msr_entry_set(&msrs[n++], MSR_MCG_CTL, env->mcg_ctl);
+       kvm_msr_entry_set(&msrs[n++], MSR_MCG_EXT_CTL, env->mcg_ext_ctl);
         for (i = 0; i < (env->mcg_cap & 0xff) * 4; i++) {
             kvm_msr_entry_set(&msrs[n++], MSR_MC0_CTL + i, env->mce_banks[i]);
         }
@@ -1811,6 +1829,9 @@ static int kvm_get_msrs(X86CPU *cpu)
     if (has_msr_feature_control) {
         msrs[n++].index = MSR_IA32_FEATURE_CONTROL;
     }
+    if (has_msr_ext_mcg_ctl) {
+       msrs[n++].index = MSR_MCG_EXT_CTL;
+    }
     if (has_msr_bndcfgs) {
         msrs[n++].index = MSR_IA32_BNDCFGS;
     }
@@ -1981,6 +2002,9 @@ static int kvm_get_msrs(X86CPU *cpu)
         case MSR_IA32_FEATURE_CONTROL:
             env->msr_ia32_feature_control = msrs[i].data;
             break;
+       case MSR_MCG_EXT_CTL:
+           env->mcg_ext_ctl = msrs[i].data;
+           break;
         case MSR_IA32_BNDCFGS:
             env->msr_bndcfgs = msrs[i].data;
             break;
-- 
2.4.3