diff mbox series

[PULL,8/8] i386: Disable TOPOEXT by default on "-cpu host"

Message ID 20180817013400.13353-9-ehabkost@redhat.com
State New
Headers show
Series [PULL,1/8] docs: add guidance on configuring CPU models for x86 | expand

Commit Message

Eduardo Habkost Aug. 17, 2018, 1:34 a.m. UTC 
Enabling TOPOEXT is always allowed, but it can't be enabled
blindly by "-cpu host" because it may make guests crash if the
rest of the cache topology information isn't provided or isn't
consistent.

This addresses the bug reported at:
https://bugzilla.redhat.com/show_bug.cgi?id=1613277

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20180809221852.15285-1-ehabkost@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target/i386/cpu.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Eduardo Habkost Aug. 21, 2018, 7:25 p.m. UTC | #1 
CCing qemu-stable.

On Thu, Aug 16, 2018 at 10:34:00PM -0300, Eduardo Habkost wrote:
> Enabling TOPOEXT is always allowed, but it can't be enabled
> blindly by "-cpu host" because it may make guests crash if the
> rest of the cache topology information isn't provided or isn't
> consistent.
> 
> This addresses the bug reported at:
> https://bugzilla.redhat.com/show_bug.cgi?id=1613277
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> Message-Id: <20180809221852.15285-1-ehabkost@redhat.com>
> Tested-by: Richard W.M. Jones <rjones@redhat.com>
> Reviewed-by: Babu Moger <babu.moger@amd.com>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
>  target/i386/cpu.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 52a77a7d08..4e4fe8fa8b 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -849,6 +849,12 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
>          },
>          .cpuid_eax = 0x80000001, .cpuid_reg = R_ECX,
>          .tcg_features = TCG_EXT3_FEATURES,
> +        /*
> +         * TOPOEXT is always allowed but can't be enabled blindly by
> +         * "-cpu host", as it requires consistent cache topology info
> +         * to be provided so it doesn't confuse guests.
> +         */
> +        .no_autoenable_flags = CPUID_EXT3_TOPOEXT,
>      },
>      [FEAT_C000_0001_EDX] = {
>          .feat_names = {
> -- 
> 2.18.0.rc1.1.g3f1ff2140
> 
>
diff mbox series

Patch

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 52a77a7d08..4e4fe8fa8b 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -849,6 +849,12 @@  static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         },
         .cpuid_eax = 0x80000001, .cpuid_reg = R_ECX,
         .tcg_features = TCG_EXT3_FEATURES,
+        /*
+         * TOPOEXT is always allowed but can't be enabled blindly by
+         * "-cpu host", as it requires consistent cache topology info
+         * to be provided so it doesn't confuse guests.
+         */
+        .no_autoenable_flags = CPUID_EXT3_TOPOEXT,
     },
     [FEAT_C000_0001_EDX] = {
         .feat_names = {