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 <ehabk...@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 <pbonz...@redhat.com>
