[PATCH 0/2] Fixes for env->user_features

[PATCH 0/2] Fixes for env->user_features

[Xiaoyao Li]

Patch 1 fixes the env->features set by versioned CPU model.

Patch 2 fixed the env->features set by unavailable_features due to
feature_dependencies[] checking.

Xiaoyao Li (2):
  i368/cpu: Clear env->user_features after loading versioned CPU model
  i386/cpu: Don't add unavailable_features to env->user_features

 target/i386/cpu.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

-- 
2.18.4

[PATCH 1/2] i368/cpu: Clear env->user_features after loading versioned CPU model

[Xiaoyao Li]

Features defined in versioned CPU model are recorded in env->user_features
since they are updated as property. It's unwated because they are not
user specified.

Simply clear env->user_features as a fix. It won't clear user specified
features because user specified features are filled to
env->user_features later in x86_cpu_expand_features().

Cc: Chenyi Qiang <chenyi.qiang@intel.com>
Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
 target/i386/cpu.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 1e5123251d74..9812d5747f35 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -5159,6 +5159,12 @@ static void x86_cpu_load_model(X86CPU *cpu, X86CPUModel *model)
     object_property_set_str(OBJECT(cpu), "vendor", vendor, &error_abort);
 
     x86_cpu_apply_version_props(cpu, model);
+
+    /* Properties in versioned CPU model are not user specified features.
+     * We can simply clear env->user_features here since it will be filled later
+     * in x86_cpu_expand_features() based on plus_features and minus_features.
+     */
+    memset(&env->user_features, 0, sizeof(env->user_features));
 }
 
 #ifndef CONFIG_USER_ONLY
-- 
2.18.4

Re: [PATCH 1/2] i368/cpu: Clear env->user_features after loading versioned CPU model

[Eduardo Habkost]

On Tue, Jul 14, 2020 at 01:44:35AM +0800, Xiaoyao Li wrote:
> Features defined in versioned CPU model are recorded in env->user_features
> since they are updated as property. It's unwated because they are not
> user specified.
> 
> Simply clear env->user_features as a fix. It won't clear user specified
> features because user specified features are filled to
> env->user_features later in x86_cpu_expand_features().
> 
> Cc: Chenyi Qiang <chenyi.qiang@intel.com>
> Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>

Reviewed-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 1e5123251d74..9812d5747f35 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -5159,6 +5159,12 @@ static void x86_cpu_load_model(X86CPU *cpu, X86CPUModel *model)
>      object_property_set_str(OBJECT(cpu), "vendor", vendor, &error_abort);
>  
>      x86_cpu_apply_version_props(cpu, model);
> +
> +    /* Properties in versioned CPU model are not user specified features.
> +     * We can simply clear env->user_features here since it will be filled later
> +     * in x86_cpu_expand_features() based on plus_features and minus_features.
> +     */
> +    memset(&env->user_features, 0, sizeof(env->user_features));
>  }
>  
>  #ifndef CONFIG_USER_ONLY
> -- 
> 2.18.4
> 

-- 
Eduardo

[PATCH 2/2] i386/cpu: Don't add unavailable_features to env->user_features

[Xiaoyao Li]

Features unavailable due to absent of their dependent features should
not be added to env->user_features. env->user_features only contains the
feature explicity specified with -feature/+feature by user.

Fixes: 99e24dbdaa68 ("target/i386: introduce generic feature dependency mechanism")
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
 target/i386/cpu.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 9812d5747f35..fb1de1bd6165 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -6370,7 +6370,6 @@ static void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
                                       unavailable_features & env->user_features[d->to.index],
                                       "This feature depends on other features that were not requested");
 
-            env->user_features[d->to.index] |= unavailable_features;
             env->features[d->to.index] &= ~unavailable_features;
         }
     }
-- 
2.18.4

Re: [PATCH 2/2] i386/cpu: Don't add unavailable_features to env->user_features

[Eduardo Habkost]

On Tue, Jul 14, 2020 at 01:44:36AM +0800, Xiaoyao Li wrote:
> Features unavailable due to absent of their dependent features should
> not be added to env->user_features. env->user_features only contains the
> feature explicity specified with -feature/+feature by user.
> 
> Fixes: 99e24dbdaa68 ("target/i386: introduce generic feature dependency mechanism")
> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>

Paolo, do you remember why that line existed?  It doesn't make
sense to me.

There are exactly 2 lines of code reading user_features, and both
of them are inside x86_cpu_expand_features() above this hunk.

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>

> ---
>  target/i386/cpu.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 9812d5747f35..fb1de1bd6165 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -6370,7 +6370,6 @@ static void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
>                                        unavailable_features & env->user_features[d->to.index],
>                                        "This feature depends on other features that were not requested");
>  
> -            env->user_features[d->to.index] |= unavailable_features;
>              env->features[d->to.index] &= ~unavailable_features;
>          }
>      }
> -- 
> 2.18.4
> 

-- 
Eduardo

Re: [PATCH 2/2] i386/cpu: Don't add unavailable_features to env->user_features

[Paolo Bonzini]

On 13/07/20 20:48, Eduardo Habkost wrote:
> On Tue, Jul 14, 2020 at 01:44:36AM +0800, Xiaoyao Li wrote:
>> Features unavailable due to absent of their dependent features should
>> not be added to env->user_features. env->user_features only contains the
>> feature explicity specified with -feature/+feature by user.
>>
>> Fixes: 99e24dbdaa68 ("target/i386: introduce generic feature dependency mechanism")
>> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> 
> Paolo, do you remember why that line existed?  It doesn't make
> sense to me.
> 
> There are exactly 2 lines of code reading user_features, and both
> of them are inside x86_cpu_expand_features() above this hunk.

I think it was just to be safe in case in the future something else adds
features automatically, in the same way as the cpu->max_features case:

            env->features[w] |=
                x86_cpu_get_supported_feature_word(w, cpu->migratable) &
                ~env->user_features[w] &
                ~feature_word_info[w].no_autoenable_flags;

It would prevent the unavailable dependent features from being added.

But yeah, it would just be enough to place it above this hunk.

Paolo

> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
> 
>> ---
>>  target/i386/cpu.c | 1 -
>>  1 file changed, 1 deletion(-)
>>
>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> index 9812d5747f35..fb1de1bd6165 100644
>> --- a/target/i386/cpu.c
>> +++ b/target/i386/cpu.c
>> @@ -6370,7 +6370,6 @@ static void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
>>                                        unavailable_features & env->user_features[d->to.index],
>>                                        "This feature depends on other features that were not requested");
>>  
>> -            env->user_features[d->to.index] |= unavailable_features;
>>              env->features[d->to.index] &= ~unavailable_features;
>>          }
>>      }
>> -- 
>> 2.18.4
>>
> 

Re: [PATCH 0/2] Fixes for env->user_features

[no-reply]

Patchew URL: https://patchew.org/QEMU/20200713174436.41070-1-xiaoyao.li@intel.com/



Hi,

This series failed the docker-quick@centos7 build test. Please find the testing commands and
their output below. If you have Docker installed, you can probably reproduce it
locally.

=== TEST SCRIPT BEGIN ===
#!/bin/bash
make docker-image-centos7 V=1 NETWORK=1
time make docker-test-quick@centos7 SHOW_ENV=1 J=14 NETWORK=1
=== TEST SCRIPT END ===

  TEST    iotest-qcow2: 022
  TEST    check-unit: tests/test-char
**
ERROR:/tmp/qemu-test/src/tests/test-char.c:1204:char_serial_test: 'chr' should not be NULL
ERROR test-char - Bail out! ERROR:/tmp/qemu-test/src/tests/test-char.c:1204:char_serial_test: 'chr' should not be NULL
make: *** [check-unit] Error 1
make: *** Waiting for unfinished jobs....
  TEST    iotest-qcow2: 024
  TEST    iotest-qcow2: 025
---
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['sudo', '-n', 'docker', 'run', '--label', 'com.qemu.instance.uuid=4939dead4d0f403ea41adb4c514af82e', '-u', '1001', '--security-opt', 'seccomp=unconfined', '--rm', '-e', 'TARGET_LIST=', '-e', 'EXTRA_CONFIGURE_OPTS=', '-e', 'V=', '-e', 'J=14', '-e', 'DEBUG=', '-e', 'SHOW_ENV=1', '-e', 'CCACHE_DIR=/var/tmp/ccache', '-v', '/home/patchew/.cache/qemu-docker-ccache:/var/tmp/ccache:z', '-v', '/var/tmp/patchew-tester-tmp-zqji5law/src/docker-src.2020-07-13-13.53.16.24512:/var/tmp/qemu:z,ro', 'qemu/centos7', '/var/tmp/qemu/run', 'test-quick']' returned non-zero exit status 2.
filter=--filter=label=com.qemu.instance.uuid=4939dead4d0f403ea41adb4c514af82e
make[1]: *** [docker-run] Error 1
make[1]: Leaving directory `/var/tmp/patchew-tester-tmp-zqji5law/src'
make: *** [docker-run-test-quick@centos7] Error 2

real    14m59.851s
user    0m9.044s


The full log is available at
http://patchew.org/logs/20200713174436.41070-1-xiaoyao.li@intel.com/testing.docker-quick@centos7/?type=message.
---
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