[PATCH] Fix for AMD erratum 383 on Family 10h CPUs

[Wei Huang <wei.huang2@amd.com>]

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This patches implements the workaround of AMD erratum 383 on family 10h 
CPUs. It destroys the guest VM when a MC error with a special pattern is 
detected. Without this patch, a guest VM failure can potentially crash 
Xen hypervisor and the whole system. The erratum will be published in 
next version of guide.

Signed-off-by: Wei Huang <wei.huang2@amd.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Christoph Egger <christoph.egger@amd.com>



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diff -r baccadfd9418 xen/arch/x86/hvm/svm/svm.c
--- a/xen/arch/x86/hvm/svm/svm.c	Fri May 14 08:05:05 2010 +0100
+++ b/xen/arch/x86/hvm/svm/svm.c	Mon May 17 07:37:19 2010 -0500
@@ -72,6 +72,9 @@
 
 /* vmcb used for extended host state */
 static void *root_vmcb[NR_CPUS] __read_mostly;
+
+/* for AMD erratum 383 */
+static bool_t amd_erratum383_found __read_mostly;
 
 static void inline __update_guest_eip(
     struct cpu_user_regs *regs, unsigned int inst_len)
@@ -828,6 +831,20 @@
     return 0;
 }
 
+static void svm_init_erratum_383(struct cpuinfo_x86 *c)
+{
+    uint64_t msr_content;
+
+    /* only family 10h is affected */
+    if ( c->x86 != 0x10 )
+        return;
+
+    rdmsrl(MSR_AMD64_DC_CFG, msr_content);
+    wrmsrl(MSR_AMD64_DC_CFG, msr_content | (1ULL << 47));
+
+    amd_erratum383_found = 1;
+}
+
 static int svm_cpu_up(struct cpuinfo_x86 *c)
 {
     u32 eax, edx, phys_hsa_lo, phys_hsa_hi;   
@@ -852,6 +869,9 @@
     phys_hsa_lo = (u32)phys_hsa;
     phys_hsa_hi = (u32)(phys_hsa >> 32);    
     wrmsr(MSR_K8_VM_HSAVE_PA, phys_hsa_lo, phys_hsa_hi);
+
+    /* check for erratum 383 */
+    svm_init_erratum_383(c);
 
     /* Initialize core's ASID handling. */
     svm_asid_init(c);
@@ -1275,6 +1295,45 @@
     }
 }
 
+extern unsigned int nr_mce_banks; /* from mce.h */
+
+static int svm_is_erratum_383(struct cpu_user_regs *regs)
+{
+    uint64_t msr_content;
+    uint32_t i;
+    struct vcpu *v = current;
+
+    if ( !amd_erratum383_found )
+        return 0;
+
+    rdmsrl(MSR_IA32_MC0_STATUS, msr_content);
+    /* Bit 62 may or may not be set for this mce */
+    msr_content &= ~(1ULL << 62);
+
+    if ( msr_content != 0xb600000000010015ULL )
+        return 0;
+    
+    /* Clear MCi_STATUS registers */
+    for (i = 0; i < nr_mce_banks; i++)
+        wrmsrl(MSR_IA32_MCx_STATUS(i), 0ULL);
+    
+    rdmsrl(MSR_IA32_MCG_STATUS, msr_content);
+    wrmsrl(MSR_IA32_MCG_STATUS, msr_content & ~(1ULL << 2));
+
+    /* flush TLB */
+    flush_tlb_mask(&v->domain->domain_dirty_cpumask);
+
+    return 1;
+}
+
+static void svm_vmexit_mce_intercept(struct vcpu *v, struct cpu_user_regs *regs)
+{
+    if ( svm_is_erratum_383(regs) ) {
+        gdprintk(XENLOG_ERR, "SVM hits AMD erratum 383\n");
+        domain_crash(v->domain);
+    }
+}
+
 static void wbinvd_ipi(void *info)
 {
     wbinvd();
@@ -1480,6 +1539,7 @@
     /* Asynchronous event, handled when we STGI'd after the VMEXIT. */
     case VMEXIT_EXCEPTION_MC:
         HVMTRACE_0D(MCE);
+        svm_vmexit_mce_intercept(v, regs);
         break;
 
     case VMEXIT_VINTR:
diff -r baccadfd9418 xen/include/asm-x86/msr-index.h
--- a/xen/include/asm-x86/msr-index.h	Fri May 14 08:05:05 2010 +0100
+++ b/xen/include/asm-x86/msr-index.h	Mon May 17 07:37:19 2010 -0500
@@ -146,6 +146,11 @@
 #define MSR_IA32_MC8_ADDR		0x00000422
 #define MSR_IA32_MC8_MISC		0x00000423
 
+#define MSR_IA32_MCx_CTL(x)             (MSR_IA32_MC0_CTL + 4*(x))
+#define MSR_IA32_MCx_STATUS(x)          (MSR_IA32_MC0_STATUS + 4*(x))
+#define MSR_IA32_MCx_ADDR(x)            (MSR_IA32_MC0_ADDR + 4*(x))
+#define MSR_IA32_MCx_MISC(x)            (MSR_IA32_MC0_MISC + 4*(x)) 
+
 #define MSR_P6_PERFCTR0			0x000000c1
 #define MSR_P6_PERFCTR1			0x000000c2
 #define MSR_P6_EVNTSEL0			0x00000186
@@ -225,6 +230,7 @@
 
 /* AMD64 MSRs */
 #define MSR_AMD64_NB_CFG		0xc001001f
+#define MSR_AMD64_DC_CFG                0xc0011022
 #define AMD64_NB_CFG_CF8_EXT_ENABLE_BIT	46
 
 /* AMD Family10h machine check MSRs */

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