[Qemu-devel] [PATCH] add rdpmc intercept for SVM

[Qemu-devel] [PATCH] add rdpmc intercept for SVM

[Bernhard Kauer]

[-- Attachment #1: Type: text/plain, Size: 194 bytes --]

The attached patch adds an SVM intercept for rdpmc to qemu,
thus allowing a VMM to virtualize them. Please note that 
performance counters are currently unimplemented in qemu.


	Bernhard Kauer

[-- Attachment #2: qemu_rdpmc.diff --]
[-- Type: text/x-diff, Size: 1241 bytes --]

Index: target-i386/helper.c
--- target-i386/helper.c	18 Nov 2007 01:44:38 -0000	1.95
+++ target-i386/helper.c	5 Dec 2007 19:31:31 -0000
@@ -2743,6 +2816,19 @@
     EDX = (uint32_t)(val >> 32);
 }
 
+void helper_rdpmc()
+{
+  if ((env->cr[4] & CR4_PCE_MASK) && ((env->hflags & HF_CPL_MASK) != 0)) {
+    raise_exception(EXCP0D_GPF);
+  }
+  
+  if (!svm_check_intercept_param(SVM_EXIT_RDPMC, 0))
+    {
+      // currently unimplemented
+      raise_exception_err(EXCP06_ILLOP, 0);
+    }
+}
+
 #if defined(CONFIG_USER_ONLY)
 void helper_wrmsr(void)
 {
Index: target-i386/op.c
--- target-i386/op.c	23 Sep 2007 15:28:04 -0000	1.51
+++ target-i386/op.c	5 Dec 2007 19:31:32 -0000
@@ -953,6 +953,11 @@
     helper_rdtsc();
 }
 
+void OPPROTO op_rdpmc(void)
+{
+    helper_rdpmc();
+}
+
 void OPPROTO op_cpuid(void)
 {
     helper_cpuid();
Index: target-i386/translate.c
--- target-i386/translate.c	8 Nov 2007 14:25:03 -0000	1.74
+++ target-i386/translate.c	5 Dec 2007 19:31:38 -0000
@@ -5653,5 +5653,9 @@
         gen_op_rdtsc();
         break;
+    case 0x133: /* rdpmc */
+        gen_jmp_im(pc_start - s->cs_base);
+        gen_op_rdpmc();
+        break;
     case 0x134: /* sysenter */
         if (CODE64(s))
             goto illegal_op;

Re: [Qemu-devel] [PATCH] add rdpmc intercept for SVM

[Alexander Graf]

On Dec 5, 2007, at 8:44 PM, Bernhard Kauer wrote:

> The attached patch adds an SVM intercept for rdpmc to qemu,
> thus allowing a VMM to virtualize them. Please note that
> performance counters are currently unimplemented in qemu.
>
>
> 	Bernhard Kauer
> <qemu_rdpmc.diff>

Sounds useful. Even though they are unimplemented, a VMM could still  
emulate them.

Signed-off-by: Alexander Graf <alex@csgraf.de>