nested vmx: enable Descriptor-table exiting for L1 VMM

Signed-off-by: Dongxiao Xu <dongxiao.xu@intel.com>
Acked-by: Jun Nakajima <jun.nakajima@intel.com>
Committed-by: Keir Fraser <keir@xen.org>

xen/arch/x86/hvm/vmx/vvmx.c

@@ -1300,7 +1300,7 @@ int nvmx_msr_read_intercept(unsigned int msr, u64 *msr_content)
         break;
     case MSR_IA32_VMX_PROCBASED_CTLS2:
         /* 1-seetings */
-        data = 0;
+        data = SECONDARY_EXEC_DESCRIPTOR_TABLE_EXITING;
         /* 0-settings */
         tmp = 0;
         data = (data << 32) | tmp;
@@ -1507,6 +1507,12 @@ int nvmx_n2_vmexit_handler(struct cpu_user_regs *regs,
         if ( ctrl & CPU_BASED_MONITOR_TRAP_FLAG)
             nvcpu->nv_vmexit_pending = 1;
         break;
+    case EXIT_REASON_ACCESS_GDTR_OR_IDTR:
+    case EXIT_REASON_ACCESS_LDTR_OR_TR:
+        ctrl = __n2_secondary_exec_control(v);
+        if ( ctrl & SECONDARY_EXEC_DESCRIPTOR_TABLE_EXITING )
+            nvcpu->nv_vmexit_pending = 1;
+        break;
     /* L1 has priority handling several other types of exits */
     case EXIT_REASON_HLT:
         ctrl = __n2_exec_control(v);

xen/include/asm-x86/hvm/vmx/vmcs.h

@@ -179,6 +179,7 @@ extern u32 vmx_vmentry_control;
 
 #define SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES 0x00000001
 #define SECONDARY_EXEC_ENABLE_EPT               0x00000002
+#define SECONDARY_EXEC_DESCRIPTOR_TABLE_EXITING 0x00000004
 #define SECONDARY_EXEC_ENABLE_RDTSCP            0x00000008
 #define SECONDARY_EXEC_ENABLE_VPID              0x00000020
 #define SECONDARY_EXEC_WBINVD_EXITING           0x00000040