diff mbox

[v3,4/6] target-i386: Remove unsupported bits from all CPU models

Message ID 1412365191-22858-5-git-send-email-ehabkost@redhat.com
State New
Headers show

Commit Message

Eduardo Habkost Oct. 3, 2014, 7:39 p.m. UTC 
The following CPU features were never supported by neither TCG or KVM,
so they are useless on the CPU model definitions, today:

 * CPUID_DTS (DS)
 * CPUID_HT
 * CPUID_TM
 * CPUID_PBE
 * CPUID_EXT_DTES64
 * CPUID_EXT_DSCPL
 * CPUID_EXT_EST
 * CPUID_EXT_TM2
 * CPUID_EXT_XTPR
 * CPUID_EXT_PDCM
 * CPUID_SVM_LBRV

As using "enforce" mode is the only way to ensure guest ABI doesn't
change when moving to a different host, we should make "enforce" mode
the default or at least encourage management software to always use it.

In turn, to make "enforce" usable, we need CPU models that work without
always requiring some features to be explicitly disabled. This patch
removes the above features from all CPU model definitions.

We won't need any machine-type compat code for those changes, because it
is impossible to have existing VMs with those features enabled.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
---
Changes v1 -> v2:
* Trivial typo fix in comment
---
 target-i386/cpu.c | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

Comments

Andreas Färber Oct. 29, 2014, 5:26 p.m. UTC | #1 
Am 03.10.2014 um 21:39 schrieb Eduardo Habkost:
> The following CPU features were never supported by neither TCG or KVM,
> so they are useless on the CPU model definitions, today:
> 
>  * CPUID_DTS (DS)
>  * CPUID_HT
>  * CPUID_TM
>  * CPUID_PBE
>  * CPUID_EXT_DTES64
>  * CPUID_EXT_DSCPL
>  * CPUID_EXT_EST
>  * CPUID_EXT_TM2
>  * CPUID_EXT_XTPR
>  * CPUID_EXT_PDCM
>  * CPUID_SVM_LBRV
> 
> As using "enforce" mode is the only way to ensure guest ABI doesn't
> change when moving to a different host, we should make "enforce" mode
> the default or at least encourage management software to always use it.
> 
> In turn, to make "enforce" usable, we need CPU models that work without
> always requiring some features to be explicitly disabled. This patch
> removes the above features from all CPU model definitions.
> 
> We won't need any machine-type compat code for those changes, because it
> is impossible to have existing VMs with those features enabled.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> Cc: Aurelien Jarno <aurelien@aurel32.net>
> ---
> Changes v1 -> v2:
> * Trivial typo fix in comment
> ---
>  target-i386/cpu.c | 33 ++++++++++++++++++++-------------
>  1 file changed, 20 insertions(+), 13 deletions(-)
> 
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 4119fca..1e9fff9 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -681,10 +681,11 @@ static X86CPUDefinition builtin_x86_defs[] = {
>          .family = 16,
>          .model = 2,
>          .stepping = 3,
> +        /* Missing: CPUID_HT */
>          .features[FEAT_1_EDX] =
>              PPRO_FEATURES |
>              CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
> -            CPUID_PSE36 | CPUID_VME | CPUID_HT,
> +            CPUID_PSE36 | CPUID_VME,
>          .features[FEAT_1_ECX] =
>              CPUID_EXT_SSE3 | CPUID_EXT_MONITOR | CPUID_EXT_CX16 |
>              CPUID_EXT_POPCNT,
[snip]

I'm okay with retaining these as comments. Anyone any objections?

Andreas
diff mbox

Patch

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 4119fca..1e9fff9 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -681,10 +681,11 @@  static X86CPUDefinition builtin_x86_defs[] = {
         .family = 16,
         .model = 2,
         .stepping = 3,
+        /* Missing: CPUID_HT */
         .features[FEAT_1_EDX] =
             PPRO_FEATURES |
             CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
-            CPUID_PSE36 | CPUID_VME | CPUID_HT,
+            CPUID_PSE36 | CPUID_VME,
         .features[FEAT_1_ECX] =
             CPUID_EXT_SSE3 | CPUID_EXT_MONITOR | CPUID_EXT_CX16 |
             CPUID_EXT_POPCNT,
@@ -700,8 +701,9 @@  static X86CPUDefinition builtin_x86_defs[] = {
         .features[FEAT_8000_0001_ECX] =
             CPUID_EXT3_LAHF_LM | CPUID_EXT3_SVM |
             CPUID_EXT3_ABM | CPUID_EXT3_SSE4A,
+        /* Missing: CPUID_SVM_LBRV */
         .features[FEAT_SVM] =
-            CPUID_SVM_NPT | CPUID_SVM_LBRV,
+            CPUID_SVM_NPT,
         .xlevel = 0x8000001A,
         .model_id = "AMD Phenom(tm) 9550 Quad-Core Processor"
     },
@@ -712,15 +714,16 @@  static X86CPUDefinition builtin_x86_defs[] = {
         .family = 6,
         .model = 15,
         .stepping = 11,
+        /* Missing: CPUID_DTS, CPUID_HT, CPUID_TM, CPUID_PBE */
         .features[FEAT_1_EDX] =
             PPRO_FEATURES |
             CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
-            CPUID_PSE36 | CPUID_VME | CPUID_DTS | CPUID_ACPI | CPUID_SS |
-            CPUID_HT | CPUID_TM | CPUID_PBE,
+            CPUID_PSE36 | CPUID_VME | CPUID_ACPI | CPUID_SS,
+        /* Missing: CPUID_EXT_DTES64, CPUID_EXT_DSCPL, CPUID_EXT_EST,
+         * CPUID_EXT_TM2, CPUID_EXT_XTPR, CPUID_EXT_PDCM */
         .features[FEAT_1_ECX] =
             CPUID_EXT_SSE3 | CPUID_EXT_MONITOR | CPUID_EXT_SSSE3 |
-            CPUID_EXT_DTES64 | CPUID_EXT_DSCPL | CPUID_EXT_VMX | CPUID_EXT_EST |
-            CPUID_EXT_TM2 | CPUID_EXT_CX16 | CPUID_EXT_XTPR | CPUID_EXT_PDCM,
+            CPUID_EXT_VMX | CPUID_EXT_CX16,
         .features[FEAT_8000_0001_EDX] =
             CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
         .features[FEAT_8000_0001_ECX] =
@@ -795,13 +798,15 @@  static X86CPUDefinition builtin_x86_defs[] = {
         .family = 6,
         .model = 14,
         .stepping = 8,
+        /* Missing: CPUID_DTS, CPUID_HT, CPUID_TM, CPUID_PBE */
         .features[FEAT_1_EDX] =
             PPRO_FEATURES | CPUID_VME |
-            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA | CPUID_DTS | CPUID_ACPI |
-            CPUID_SS | CPUID_HT | CPUID_TM | CPUID_PBE,
+            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA | CPUID_ACPI |
+            CPUID_SS,
+        /* Missing: CPUID_EXT_EST, CPUID_EXT_TM2 , CPUID_EXT_XTPR,
+         * CPUID_EXT_PDCM */
         .features[FEAT_1_ECX] =
-            CPUID_EXT_SSE3 | CPUID_EXT_MONITOR | CPUID_EXT_VMX |
-            CPUID_EXT_EST | CPUID_EXT_TM2 | CPUID_EXT_XTPR | CPUID_EXT_PDCM,
+            CPUID_EXT_SSE3 | CPUID_EXT_MONITOR | CPUID_EXT_VMX,
         .features[FEAT_8000_0001_EDX] =
             CPUID_EXT2_NX,
         .xlevel = 0x80000008,
@@ -874,14 +879,16 @@  static X86CPUDefinition builtin_x86_defs[] = {
         .family = 6,
         .model = 28,
         .stepping = 2,
+        /* Missing: CPUID_DTS, CPUID_HT, CPUID_TM, CPUID_PBE */
         .features[FEAT_1_EDX] =
             PPRO_FEATURES |
-            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA | CPUID_VME | CPUID_DTS |
-            CPUID_ACPI | CPUID_SS | CPUID_HT | CPUID_TM | CPUID_PBE,
+            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA | CPUID_VME |
+            CPUID_ACPI | CPUID_SS,
             /* Some CPUs got no CPUID_SEP */
+        /* Missing: CPUID_EXT_DSCPL, CPUID_EXT_EST, CPUID_EXT_TM2,
+         * CPUID_EXT_XTPR */
         .features[FEAT_1_ECX] =
             CPUID_EXT_SSE3 | CPUID_EXT_MONITOR | CPUID_EXT_SSSE3 |
-            CPUID_EXT_DSCPL | CPUID_EXT_EST | CPUID_EXT_TM2 | CPUID_EXT_XTPR |
             CPUID_EXT_MOVBE,
         .features[FEAT_8000_0001_EDX] =
             (PPRO_FEATURES & CPUID_EXT2_AMD_ALIASES) |