[Xen-devel] [PATCH] Enhance the vmce injection check logic

["Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>]

Enhance the vmce injection check logic

Currently we will not inject vMCE if guest has different mca control register 
setup.

This is not enough, we need consider more. If guest has different family/model, 
we should not inject guest, because the MCA error code include model specific 
information. If guest has not enabled MCE (i.e. CR4.X86_CR4_MCE is clear), we 
should not inject vMCE.

One thing need notice. In the memory error handler, we didn't kill the guest if 
vMCE is not ready, instead, we will simply ignore the vMCE. In native, system 
will reboot if MCE in CR4 is not enabled. We need contain guest access to the 
broken memory through eithe software or hardware method.

Signed-off-by: Jiang, Yunhong <yunhong.jiang@xxxxxxxxx>

diff -r 967d3f845cfb xen/arch/x86/cpu/mcheck/mce.h
--- a/xen/arch/x86/cpu/mcheck/mce.h     Sat Jun 12 09:31:37 2010 +0800
+++ b/xen/arch/x86/cpu/mcheck/mce.h     Sat Jun 12 10:41:47 2010 +0800
@@ -48,9 +48,10 @@ void mce_intel_feature_init(struct cpuin
 void mce_intel_feature_init(struct cpuinfo_x86 *c);
 void amd_nonfatal_mcheck_init(struct cpuinfo_x86 *c);
 
+int is_vmce_ready(struct mcinfo_bank *bank, struct domain *d);
+
 u64 mce_cap_init(void);
 extern int firstbank;
-int mca_ctl_conflict(struct mcinfo_bank *bank, struct domain *d);
 
 int intel_mce_rdmsr(uint32_t msr, uint64_t *val);
 int intel_mce_wrmsr(uint32_t msr, uint64_t val);
diff -r 967d3f845cfb xen/arch/x86/cpu/mcheck/mce_intel.c
--- a/xen/arch/x86/cpu/mcheck/mce_intel.c       Sat Jun 12 09:31:37 2010 +0800
+++ b/xen/arch/x86/cpu/mcheck/mce_intel.c       Sat Jun 12 10:41:47 2010 +0800
@@ -654,9 +654,9 @@ static void intel_memerr_dhandler(int bn
             BUG_ON( result->owner == DOMID_COW );
             if ( result->owner != DOMID_XEN ) {
                 d = get_domain_by_id(result->owner);
-                if ( mca_ctl_conflict(bank, d) )
+                if ( !is_vmce_ready(bank, d) )
                 {
-                    /* Guest has different MCE ctl with hypervisor */
+                    /* Should not inject vMCE to guest */
                     if ( d )
                         put_domain(d);
                     return;
diff -r 967d3f845cfb xen/arch/x86/cpu/mcheck/vmce.c
--- a/xen/arch/x86/cpu/mcheck/vmce.c    Sat Jun 12 09:31:37 2010 +0800
+++ b/xen/arch/x86/cpu/mcheck/vmce.c    Sat Jun 12 10:48:50 2010 +0800
@@ -468,7 +468,7 @@ int vmce_init(struct cpuinfo_x86 *c)
     return 0;
 }
 
-int mca_ctl_conflict(struct mcinfo_bank *bank, struct domain *d)
+static int mca_ctl_conflict(struct mcinfo_bank *bank, struct domain *d)
 {
     int bank_nr;
 
@@ -484,3 +484,79 @@ int mca_ctl_conflict(struct mcinfo_bank 
         return 1;
     return 0;
 }
+
+static int is_hvm_vmce_ready(struct mcinfo_bank *bank, struct domain *d)
+{
+    struct vcpu *v;
+    int no_vmce = 0, i;
+
+    if (!is_hvm_domain(d))
+        return 0;
+
+    /* kill guest if not enabled vMCE */
+    for_each_vcpu(d, v)
+    {
+        if (!(v->arch.hvm_vcpu.guest_cr[4] & X86_CR4_MCE))
+        {
+            no_vmce = 1;
+            break;
+        }
+
+        if (!mce_broadcast)
+            break;
+    }
+
+    if (no_vmce)
+        return 0;
+
+    /* Guest has virtualized family/model information */
+    for ( i = 0; i < MAX_CPUID_INPUT; i++ )
+    {
+        if (d->arch.cpuids[i].input[0] == 0x1)
+        {
+            uint32_t veax = d->arch.cpuids[i].eax, vfam, vmod;
+
+                       vfam = (veax >> 8) & 15;
+                       vmod = (veax >> 4) & 15;
+
+            if (vfam == 0x6 || vfam == 0xf)
+                vmod += ((veax >> 16) & 0xF) << 4;
+                       if (vfam == 0xf)
+                               vfam += (veax >> 20) & 0xff;
+
+            if ( ( vfam != boot_cpu_data.x86 ) ||
+                 (vmod != boot_cpu_data.x86_model) )
+            {
+                dprintk(XENLOG_WARNING,
+                    "No vmce for different virtual family/model cpuid\n");
+                no_vmce = 1;
+            }
+            break;
+        }
+    }
+
+    if (no_vmce)
+        return 0;
+
+    /* Guest has different MCE ctl value setting */
+    if (mca_ctl_conflict(bank, d))
+    {
+        dprintk(XENLOG_WARNING,
+          "No vmce, guest has different mca control setting\n");
+        return 0;
+    }
+
+    return 1;
+}
+
+int is_vmce_ready(struct mcinfo_bank *bank, struct domain *d)
+{
+    if ( d == dom0)
+        return dom0_vmce_enabled();
+
+    /* No vMCE to HVM guest now */
+    if ( is_hvm_domain(d) )
+        return is_hvm_vmce_ready(bank, d);
+
+    return 0;
+}

Attachment: vmce_check.patch
Description: vmce_check.patch

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