xen-devel.lists.xenproject.org archive mirror
 help / color / mirror / Atom feed
From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>,
	Wei Liu <wei.liu2@citrix.com>,
	Roger Pau Monne <roger.pau@citrix.com>
Subject: Re: [PATCH] libx86: Elide more empty CPUID leaves when serialising a policy
Date: Thu, 23 May 2019 11:38:27 +0100	[thread overview]
Message-ID: <1292e300-400d-5612-76aa-8139c1e0c7fa@citrix.com> (raw)
In-Reply-To: <5CE65AF002000078002319A7@prv1-mh.provo.novell.com>

On 23/05/2019 09:33, Jan Beulich wrote:
>>>> On 22.05.19 at 17:50, <andrew.cooper3@citrix.com> wrote:
>> x86_cpuid_copy_to_buffer() currently serialises the full content of the
>> various subleaf unions.  While leaves 4, 0xb and 0xd don't have a concrete
>> max_subleaf field, they do have well defined upper bounds.
>>
>> Diffing the results of `xen-cpuid -p` shows the resutling saving:
>>
>>   @@ -1,5 +1,5 @@
>>    Xen reports there are maximum 114 leaves and 1 MSRs
>>   -Raw policy: 93 leaves, 1 MSRs
>>   +Raw policy: 38 leaves, 1 MSRs
>>     CPUID:
>>      leaf     subleaf  -> eax      ebx      ecx      edx
>>      00000000:ffffffff -> 00000016:756e6547:6c65746e:49656e69
>>   @@ -32,7 +32,7 @@ Raw policy: 93 leaves, 1 MSRs
>>     MSRs:
>>      index    -> value
>>      000000ce -> 0000000080000000
>>   -Host policy: 93 leaves, 1 MSRs
>>   +Host policy: 33 leaves, 1 MSRs
>>     CPUID:
>>      leaf     subleaf  -> eax      ebx      ecx      edx
>>      00000000:ffffffff -> 0000000d:756e6547:6c65746e:49656e69
>>
>> which is mostly due to no longer writing out 64 leaves for xstate when (on
>> this CoffeeLake system) 8 will do.
>>
>> Extend the unit tests to cover empty and partially filled subleaf unions.
>>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> For the lib/x86/ part
> Reviewed-by: Jan Beulich <jbeulich@suse.com>

Thanks.

> For the test harness part
> Acked-by: Jan Beulich <jbeulich@suse.com>
> No idea how else I should represent that I didn't look overly closely
> at the harness additions.

Well - I can state that the additions to the test harness did find bugs.

Overall, I think the content of tools/tests/ is of relatively little
importance in the grand scheme of things.  I certainly don't spend as
much time reviewing the test_x86_emulator changes as the changes to
x86_emulate() itself.

~Andrew

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

WARNING: multiple messages have this Message-ID (diff)
From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>,
	Wei Liu <wei.liu2@citrix.com>,
	Roger Pau Monne <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH] libx86: Elide more empty CPUID leaves when serialising a policy
Date: Thu, 23 May 2019 11:38:27 +0100	[thread overview]
Message-ID: <1292e300-400d-5612-76aa-8139c1e0c7fa@citrix.com> (raw)
Message-ID: <20190523103827.Ue8BslnSZFqyJuWtV4PoSyk6yOkVKfQZQIu538xjg4k@z> (raw)
In-Reply-To: <5CE65AF002000078002319A7@prv1-mh.provo.novell.com>

On 23/05/2019 09:33, Jan Beulich wrote:
>>>> On 22.05.19 at 17:50, <andrew.cooper3@citrix.com> wrote:
>> x86_cpuid_copy_to_buffer() currently serialises the full content of the
>> various subleaf unions.  While leaves 4, 0xb and 0xd don't have a concrete
>> max_subleaf field, they do have well defined upper bounds.
>>
>> Diffing the results of `xen-cpuid -p` shows the resutling saving:
>>
>>   @@ -1,5 +1,5 @@
>>    Xen reports there are maximum 114 leaves and 1 MSRs
>>   -Raw policy: 93 leaves, 1 MSRs
>>   +Raw policy: 38 leaves, 1 MSRs
>>     CPUID:
>>      leaf     subleaf  -> eax      ebx      ecx      edx
>>      00000000:ffffffff -> 00000016:756e6547:6c65746e:49656e69
>>   @@ -32,7 +32,7 @@ Raw policy: 93 leaves, 1 MSRs
>>     MSRs:
>>      index    -> value
>>      000000ce -> 0000000080000000
>>   -Host policy: 93 leaves, 1 MSRs
>>   +Host policy: 33 leaves, 1 MSRs
>>     CPUID:
>>      leaf     subleaf  -> eax      ebx      ecx      edx
>>      00000000:ffffffff -> 0000000d:756e6547:6c65746e:49656e69
>>
>> which is mostly due to no longer writing out 64 leaves for xstate when (on
>> this CoffeeLake system) 8 will do.
>>
>> Extend the unit tests to cover empty and partially filled subleaf unions.
>>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> For the lib/x86/ part
> Reviewed-by: Jan Beulich <jbeulich@suse.com>

Thanks.

> For the test harness part
> Acked-by: Jan Beulich <jbeulich@suse.com>
> No idea how else I should represent that I didn't look overly closely
> at the harness additions.

Well - I can state that the additions to the test harness did find bugs.

Overall, I think the content of tools/tests/ is of relatively little
importance in the grand scheme of things.  I certainly don't spend as
much time reviewing the test_x86_emulator changes as the changes to
x86_emulate() itself.

~Andrew

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

  parent reply	other threads:[~2019-05-23 10:38 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-22 15:50 [PATCH] libx86: Elide more empty CPUID leaves when serialising a policy Andrew Cooper
2019-05-22 15:50 ` [Xen-devel] " Andrew Cooper
2019-05-23  8:33 ` Jan Beulich
2019-05-23  8:33   ` [Xen-devel] " Jan Beulich
2019-05-23 10:38   ` Andrew Cooper [this message]
2019-05-23 10:38     ` Andrew Cooper
2019-05-23 10:27 ` [PATCH] libx86: Introduce wrappers for extracting XCR0/XSS from a cpuid policy Andrew Cooper
2019-05-23 10:27   ` [Xen-devel] " Andrew Cooper
2019-05-23 11:52   ` Jan Beulich
2019-05-23 11:52     ` [Xen-devel] " Jan Beulich
2019-05-23 11:59     ` Andrew Cooper
2019-05-23 11:59       ` [Xen-devel] " Andrew Cooper
2019-05-23 12:08       ` Jan Beulich
2019-05-23 12:08         ` [Xen-devel] " Jan Beulich

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1292e300-400d-5612-76aa-8139c1e0c7fa@citrix.com \
    --to=andrew.cooper3@citrix.com \
    --cc=JBeulich@suse.com \
    --cc=roger.pau@citrix.com \
    --cc=wei.liu2@citrix.com \
    --cc=xen-devel@lists.xenproject.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).