Nested Virtualization: efer

diff -r 7789f1d7d7e7 -r 8c7c597735c6 xen/arch/x86/hvm/hvm.c
@@ -616,6 +616,7 @@ static bool_t hvm_efer_valid(uint64_t va
 {
     return !((value & ~efer_validbits) ||
              ((sizeof(long) != 8) && (value & EFER_LME)) ||
+             (!cpu_has_svm && (value & EFER_SVME)) ||
              (!cpu_has_nx && (value & EFER_NX)) ||
              (!cpu_has_syscall && (value & EFER_SCE)) ||
              (!cpu_has_lmsl && (value & EFER_LMSLE)) ||

@@ -630,6 +631,7 @@ static int hvm_load_cpu_ctxt(struct doma
     struct hvm_hw_cpu ctxt;
     struct segment_register seg;
     struct vcpu_guest_context *vc;
+    uint64_t efer_validbits;
 
     /* Which vcpu is this? */
     vcpuid = hvm_load_instance(h);

@@ -669,9 +671,12 @@ static int hvm_load_cpu_ctxt(struct doma
         return -EINVAL;
     }
 
-    if ( !hvm_efer_valid(
-        ctxt.msr_efer,
-        EFER_FFXSE | EFER_LMSLE | EFER_LME | EFER_LMA | EFER_NX | EFER_SCE) )
+    efer_validbits = EFER_FFXSE | EFER_LMSLE | EFER_LME | EFER_LMA
+                   | EFER_NX | EFER_SCE;
+    if ( nestedhvm_enabled(v->domain) )
+        efer_validbits |= EFER_SVME;
+
+    if ( !hvm_efer_valid(ctxt.msr_efer, efer_validbits) )
     {
         gdprintk(XENLOG_ERR, "HVM restore: bad EFER 0x%"PRIx64"\n",
                  ctxt.msr_efer);

@@ -1081,14 +1086,18 @@ bool_t hvm_hap_nested_page_fault(unsigne
 int hvm_set_efer(uint64_t value)
 {
     struct vcpu *v = current;
+    uint64_t efer_validbits;
 
     value &= ~EFER_LMA;
 
-    if ( !hvm_efer_valid(value,
-            EFER_FFXSE | EFER_LMSLE | EFER_LME | EFER_NX | EFER_SCE) )
+    efer_validbits = EFER_FFXSE | EFER_LMSLE | EFER_LME | EFER_NX | EFER_SCE;
+    if ( nestedhvm_enabled(v->domain) )
+        efer_validbits |= EFER_SVME;
+
+    if ( !hvm_efer_valid(value, efer_validbits) )
     {
         gdprintk(XENLOG_WARNING, "Trying to set reserved bit in "
-                 "EFER: %"PRIx64"\n", value);
+                 "EFER: 0x%"PRIx64"\n", value);
         hvm_inject_exception(TRAP_gp_fault, 0, 0);
         return X86EMUL_EXCEPTION;
     }

diff -r 7789f1d7d7e7 -r 8c7c597735c6 xen/include/asm-x86/cpufeature.h
@@ -199,6 +199,8 @@
 
 #define cpu_has_rdtscp          boot_cpu_has(X86_FEATURE_RDTSCP)
 
+#define cpu_has_svm		boot_cpu_has(X86_FEATURE_SVME)
+
 #endif /* __ASM_I386_CPUFEATURE_H */
 
 /*