* [Qemu-devel] [PATCH] target-i386: Remove POPCNT from qemu64 and qemu32 CPU models
@ 2015-11-04 15:35 Eduardo Habkost
2015-11-04 16:00 ` Paolo Bonzini
0 siblings, 1 reply; 2+ messages in thread
From: Eduardo Habkost @ 2015-11-04 15:35 UTC (permalink / raw)
To: qemu-devel
Cc: Paolo Bonzini, Igor Mammedov, Richard Henderson,
Dr. David Alan Gilbert, Michael S. Tsirkin
POPCNT is not available on Penryn and older and on Opteron_G2 and older,
and we want to make the default CPU runnable in most hosts, so it won't
be enabled by default in KVM mode.
We should eventually have all features supported by TCG enabled by
default in TCG mode, but as we don't have a good mechanism today to
ensure we have different defaults in KVM and TCG mode, disable POPCNT in
the qemu64 and qemu32 CPU models entirely.
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
This patch needs to be applied after the series:
Subject: [PATCH v2 0/3] target-i386: Don't trigger CPUID warnings by
default in KVM mode (in most hosts)
---
include/hw/i386/pc.h | 10 ++++++++++
target-i386/cpu.c | 4 ++--
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 8b54863..4bbc0ff 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -337,6 +337,16 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t *);
.driver = "qemu64" "-" TYPE_X86_CPU,\
.property = "abm",\
.value = "on",\
+ },\
+ {\
+ .driver = "qemu64" "-" TYPE_X86_CPU,\
+ .property = "popcnt",\
+ .value = "on",\
+ },\
+ {\
+ .driver = "qemu32" "-" TYPE_X86_CPU,\
+ .property = "popcnt",\
+ .value = "on",\
},
#define PC_COMPAT_2_3 \
diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 35cd267..5a62ef5 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -671,7 +671,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
CPUID_PSE36,
.features[FEAT_1_ECX] =
- CPUID_EXT_SSE3 | CPUID_EXT_CX16 | CPUID_EXT_POPCNT,
+ CPUID_EXT_SSE3 | CPUID_EXT_CX16,
.features[FEAT_8000_0001_EDX] =
CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
.features[FEAT_8000_0001_ECX] =
@@ -771,7 +771,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
.features[FEAT_1_EDX] =
PPRO_FEATURES,
.features[FEAT_1_ECX] =
- CPUID_EXT_SSE3 | CPUID_EXT_POPCNT,
+ CPUID_EXT_SSE3,
.xlevel = 0x80000004,
},
{
--
2.1.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [Qemu-devel] [PATCH] target-i386: Remove POPCNT from qemu64 and qemu32 CPU models
2015-11-04 15:35 [Qemu-devel] [PATCH] target-i386: Remove POPCNT from qemu64 and qemu32 CPU models Eduardo Habkost
@ 2015-11-04 16:00 ` Paolo Bonzini
0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2015-11-04 16:00 UTC (permalink / raw)
To: Eduardo Habkost, qemu-devel
Cc: Igor Mammedov, Richard Henderson, Dr. David Alan Gilbert,
Michael S. Tsirkin
On 04/11/2015 16:35, Eduardo Habkost wrote:
> POPCNT is not available on Penryn and older and on Opteron_G2 and older,
> and we want to make the default CPU runnable in most hosts, so it won't
> be enabled by default in KVM mode.
>
> We should eventually have all features supported by TCG enabled by
> default in TCG mode, but as we don't have a good mechanism today to
> ensure we have different defaults in KVM and TCG mode, disable POPCNT in
> the qemu64 and qemu32 CPU models entirely.
>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
> This patch needs to be applied after the series:
> Subject: [PATCH v2 0/3] target-i386: Don't trigger CPUID warnings by
> default in KVM mode (in most hosts)
> ---
> include/hw/i386/pc.h | 10 ++++++++++
> target-i386/cpu.c | 4 ++--
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index 8b54863..4bbc0ff 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -337,6 +337,16 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t *);
> .driver = "qemu64" "-" TYPE_X86_CPU,\
> .property = "abm",\
> .value = "on",\
> + },\
> + {\
> + .driver = "qemu64" "-" TYPE_X86_CPU,\
> + .property = "popcnt",\
> + .value = "on",\
> + },\
> + {\
> + .driver = "qemu32" "-" TYPE_X86_CPU,\
> + .property = "popcnt",\
> + .value = "on",\
> },
>
> #define PC_COMPAT_2_3 \
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 35cd267..5a62ef5 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -671,7 +671,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
> CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
> CPUID_PSE36,
> .features[FEAT_1_ECX] =
> - CPUID_EXT_SSE3 | CPUID_EXT_CX16 | CPUID_EXT_POPCNT,
> + CPUID_EXT_SSE3 | CPUID_EXT_CX16,
> .features[FEAT_8000_0001_EDX] =
> CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
> .features[FEAT_8000_0001_ECX] =
> @@ -771,7 +771,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
> .features[FEAT_1_EDX] =
> PPRO_FEATURES,
> .features[FEAT_1_ECX] =
> - CPUID_EXT_SSE3 | CPUID_EXT_POPCNT,
> + CPUID_EXT_SSE3,
> .xlevel = 0x80000004,
> },
> {
>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2015-11-04 15:35 [Qemu-devel] [PATCH] target-i386: Remove POPCNT from qemu64 and qemu32 CPU models Eduardo Habkost
2015-11-04 16:00 ` Paolo Bonzini
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