[Xen-changelog] [xen-unstable] nested vmx: check host ability when intercept MSR read

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Dongxiao Xu <dongxiao.xu@xxxxxxxxx>
# Date 1354813167 0
# Node ID 12d2786dc549b4944d58d1e347ac423842d1259d
# Parent  90831c29bfde6aac013b7e5ec98934a4953c31c9
nested vmx: check host ability when intercept MSR read

When guest hypervisor tries to read MSR value, we intercept this
behavior and return certain emulated values. Besides that, we also
need to ensure that those emulated values must compatible with host
ability.

Signed-off-by: Dongxiao Xu <dongxiao.xu@xxxxxxxxx>
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
Committed-by: Keir Fraser <keir@xxxxxxx>
---


diff -r 90831c29bfde -r 12d2786dc549 xen/arch/x86/hvm/vmx/vvmx.c
--- a/xen/arch/x86/hvm/vmx/vvmx.c       Thu Dec 06 16:58:59 2012 +0000
+++ b/xen/arch/x86/hvm/vmx/vvmx.c       Thu Dec 06 16:59:27 2012 +0000
@@ -1314,24 +1314,32 @@ int nvmx_handle_vmwrite(struct cpu_user_
     return X86EMUL_OKAY;
 }
 
+#define __emul_value(enable1, default1) \
+    ((enable1 | default1) << 32 | (default1))
+
+#define gen_vmx_msr(enable1, default1, host_value) \
+    (((__emul_value(enable1, default1) & host_value) & (~0ul << 32)) | \
+    ((uint32_t)(__emul_value(enable1, default1) | host_value)))
+
 /*
  * Capability reporting
  */
 int nvmx_msr_read_intercept(unsigned int msr, u64 *msr_content)
 {
-    u64 data = 0, tmp = 0;
+    u64 data = 0, host_data = 0;
     int r = 1;
 
     if ( !nestedhvm_enabled(current->domain) )
         return 0;
 
+    rdmsrl(msr, host_data);
+
     /*
      * Remove unsupport features from n1 guest capability MSR
      */
     switch (msr) {
     case MSR_IA32_VMX_BASIC:
-        data = VVMCS_REVISION | ((u64)PAGE_SIZE) << 32 | 
-               ((u64)MTRR_TYPE_WRBACK) << 50 | VMX_BASIC_DEFAULT1_ZERO;
+        data = (host_data & (~0ul << 32)) | VVMCS_REVISION;
         break;
     case MSR_IA32_VMX_PINBASED_CTLS:
     case MSR_IA32_VMX_TRUE_PINBASED_CTLS:
@@ -1339,8 +1347,7 @@ int nvmx_msr_read_intercept(unsigned int
         data = PIN_BASED_EXT_INTR_MASK |
                PIN_BASED_NMI_EXITING |
                PIN_BASED_PREEMPT_TIMER;
-        tmp = VMX_PINBASED_CTLS_DEFAULT1;
-        data = ((data | tmp) << 32) | (tmp);
+        data = gen_vmx_msr(data, VMX_PINBASED_CTLS_DEFAULT1, host_data);
         break;
     case MSR_IA32_VMX_PROCBASED_CTLS:
     case MSR_IA32_VMX_TRUE_PROCBASED_CTLS:
@@ -1365,22 +1372,17 @@ int nvmx_msr_read_intercept(unsigned int
                CPU_BASED_PAUSE_EXITING |
                CPU_BASED_RDPMC_EXITING |
                CPU_BASED_ACTIVATE_SECONDARY_CONTROLS;
-        tmp = VMX_PROCBASED_CTLS_DEFAULT1;
-        /* 0-settings */
-        data = ((data | tmp) << 32) | (tmp);
+        data = gen_vmx_msr(data, VMX_PROCBASED_CTLS_DEFAULT1, host_data);
         break;
     case MSR_IA32_VMX_PROCBASED_CTLS2:
         /* 1-seetings */
         data = SECONDARY_EXEC_DESCRIPTOR_TABLE_EXITING |
                SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
-        /* 0-settings */
-        tmp = 0;
-        data = (data << 32) | tmp;
+        data = gen_vmx_msr(data, 0, host_data);
         break;
     case MSR_IA32_VMX_EXIT_CTLS:
     case MSR_IA32_VMX_TRUE_EXIT_CTLS:
         /* 1-seetings */
-        tmp = VMX_EXIT_CTLS_DEFAULT1;
         data = VM_EXIT_ACK_INTR_ON_EXIT |
                VM_EXIT_IA32E_MODE |
                VM_EXIT_SAVE_PREEMPT_TIMER |
@@ -1389,18 +1391,16 @@ int nvmx_msr_read_intercept(unsigned int
                VM_EXIT_SAVE_GUEST_EFER |
                VM_EXIT_LOAD_HOST_EFER |
                VM_EXIT_LOAD_PERF_GLOBAL_CTRL;
-       /* 0-settings */
-        data = ((data | tmp) << 32) | tmp;
+        data = gen_vmx_msr(data, VMX_EXIT_CTLS_DEFAULT1, host_data);
         break;
     case MSR_IA32_VMX_ENTRY_CTLS:
     case MSR_IA32_VMX_TRUE_ENTRY_CTLS:
         /* 1-seetings */
-        tmp = VMX_ENTRY_CTLS_DEFAULT1;
         data = VM_ENTRY_LOAD_GUEST_PAT |
                VM_ENTRY_LOAD_GUEST_EFER |
                VM_ENTRY_LOAD_PERF_GLOBAL_CTRL |
                VM_ENTRY_IA32E_MODE;
-        data = ((data | tmp) << 32) | tmp;
+        data = gen_vmx_msr(data, VMX_ENTRY_CTLS_DEFAULT1, host_data);
         break;
 
     case IA32_FEATURE_CONTROL_MSR:

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