[Qemu-devel] [QEMU PATCH] target-i386: Disable rdtscp on Opteron_G* CPU models

[Eduardo Habkost]

KVM can't virtualize rdtscp on AMD CPUs yet, so there's no point
in enabling it by default on AMD CPU models, as all we are
getting are confused users because of the "host doesn't support
requested feature" warnings.

Disable rdtscp on Opteron_G* models, but keep compatibility on
pc-*-2.4 and older (just in case there are people are doing funny
stuff using AMD CPU models on Intel hosts).

Signed-off-by: Eduardo Habkost <address@hidden>
---
 include/hw/i386/pc.h | 17 +++++++++++++++++
 target-i386/cpu.c    | 12 ++++++++----
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 4bbc0ff..854c330 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -347,8 +347,25 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t *);
             .driver   = "qemu32" "-" TYPE_X86_CPU,\
             .property = "popcnt",\
             .value    = "on",\
+        },{\
+            .driver   = "Opteron_G2" "-" TYPE_X86_CPU,\
+            .property = "rdtscp",\
+            .value    = "on",\
+        },{\
+            .driver   = "Opteron_G3" "-" TYPE_X86_CPU,\
+            .property = "rdtscp",\
+            .value    = "on",\
+        },{\
+            .driver   = "Opteron_G4" "-" TYPE_X86_CPU,\
+            .property = "rdtscp",\
+            .value    = "on",\
+        },{\
+            .driver   = "Opteron_G5" "-" TYPE_X86_CPU,\
+            .property = "rdtscp",\
+            .value    = "on",\
         },
 
+
 #define PC_COMPAT_2_3 \
         PC_COMPAT_2_4 \
         HW_COMPAT_2_3 \
diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index e5f1c5b..11e5e39 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -1244,8 +1244,9 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_DE | CPUID_FP87,
         .features[FEAT_1_ECX] =
             CPUID_EXT_CX16 | CPUID_EXT_SSE3,
+        /* Missing: CPUID_EXT2_RDTSCP */
         .features[FEAT_8000_0001_EDX] =
-            CPUID_EXT2_LM | CPUID_EXT2_RDTSCP | CPUID_EXT2_FXSR |
+            CPUID_EXT2_LM | CPUID_EXT2_FXSR |
             CPUID_EXT2_MMX | CPUID_EXT2_NX | CPUID_EXT2_PSE36 |
             CPUID_EXT2_PAT | CPUID_EXT2_CMOV | CPUID_EXT2_MCA |
             CPUID_EXT2_PGE | CPUID_EXT2_MTRR | CPUID_EXT2_SYSCALL |
@@ -1273,8 +1274,9 @@ static X86CPUDefinition builtin_x86_defs[] = {
         .features[FEAT_1_ECX] =
             CPUID_EXT_POPCNT | CPUID_EXT_CX16 | CPUID_EXT_MONITOR |
             CPUID_EXT_SSE3,
+        /* Missing: CPUID_EXT2_RDTSCP */
         .features[FEAT_8000_0001_EDX] =
-            CPUID_EXT2_LM | CPUID_EXT2_RDTSCP | CPUID_EXT2_FXSR |
+            CPUID_EXT2_LM | CPUID_EXT2_FXSR |
             CPUID_EXT2_MMX | CPUID_EXT2_NX | CPUID_EXT2_PSE36 |
             CPUID_EXT2_PAT | CPUID_EXT2_CMOV | CPUID_EXT2_MCA |
             CPUID_EXT2_PGE | CPUID_EXT2_MTRR | CPUID_EXT2_SYSCALL |
@@ -1305,8 +1307,9 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT_POPCNT | CPUID_EXT_SSE42 | CPUID_EXT_SSE41 |
             CPUID_EXT_CX16 | CPUID_EXT_SSSE3 | CPUID_EXT_PCLMULQDQ |
             CPUID_EXT_SSE3,
+        /* Missing: CPUID_EXT2_RDTSCP */
         .features[FEAT_8000_0001_EDX] =
-            CPUID_EXT2_LM | CPUID_EXT2_RDTSCP |
+            CPUID_EXT2_LM |
             CPUID_EXT2_PDPE1GB | CPUID_EXT2_FXSR | CPUID_EXT2_MMX |
             CPUID_EXT2_NX | CPUID_EXT2_PSE36 | CPUID_EXT2_PAT |
             CPUID_EXT2_CMOV | CPUID_EXT2_MCA | CPUID_EXT2_PGE |
@@ -1340,8 +1343,9 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT_AES | CPUID_EXT_POPCNT | CPUID_EXT_SSE42 |
             CPUID_EXT_SSE41 | CPUID_EXT_CX16 | CPUID_EXT_FMA |
             CPUID_EXT_SSSE3 | CPUID_EXT_PCLMULQDQ | CPUID_EXT_SSE3,
+        /* Missing: CPUID_EXT2_RDTSCP */
         .features[FEAT_8000_0001_EDX] =
-            CPUID_EXT2_LM | CPUID_EXT2_RDTSCP |
+            CPUID_EXT2_LM |
             CPUID_EXT2_PDPE1GB | CPUID_EXT2_FXSR | CPUID_EXT2_MMX |
             CPUID_EXT2_NX | CPUID_EXT2_PSE36 | CPUID_EXT2_PAT |
             CPUID_EXT2_CMOV | CPUID_EXT2_MCA | CPUID_EXT2_PGE |
-- 
2.1.0