Re: [Qemu-devel] [PULL 0/1] i386: Don't automatically enable FEAT_KVM_HINTS bits

[Peter Maydell]

On 16 April 2018 at 18:46, Eduardo Habkost <address@hidden> wrote:
> On Mon, Apr 16, 2018 at 02:42:52PM -0300, Eduardo Habkost wrote:
>> On Mon, Apr 16, 2018 at 05:57:35PM +0100, Peter Maydell wrote:
>> > On 16 April 2018 at 17:39, Eduardo Habkost <address@hidden> wrote:
>> > > Last remaining fix for -rc4.
>> > >
>> > > The following changes since commit 
>> > > 042f6a31af3d38eefc6ec995cce1d762c41d4515:
>> > >
>> > >   Merge remote-tracking branch 
>> > > 'remotes/maxreitz/tags/pull-block-2018-04-16' into staging (2018-04-16 
>> > > 15:30:54 +0100)
>> > >
>> > > are available in the Git repository at:
>> > >
>> > >   git://github.com/ehabkost/qemu.git tags/x86-next-pull-request
>> > >
>> > > for you to fetch changes up to 0d914f39a77954bf5472b16130aeefe573a068f5:
>> > >
>> > >   i386: Don't automatically enable FEAT_KVM_HINTS bits (2018-04-16 
>> > > 13:36:52 -0300)
>> > >
>> > > ----------------------------------------------------------------
>> > > i386: Don't automatically enable FEAT_KVM_HINTS bits
>> > >
>> > > Bug fix for "-cpu host" with newer kernels.
>> > >
>> > > ----------------------------------------------------------------
>> >
>> > Is this a regression since 2.11 ?
>>
>> Yes.
>
> For reference, it was introduced by:
>
> commit be7773268d98176489483a315d3e2323cb0615b9
> Author: Wanpeng Li <address@hidden>
> Date:   Fri Feb 9 06:15:25 2018 -0800
>
>     target-i386: add KVM_HINTS_DEDICATED performance hint
>
>     Add KVM_HINTS_DEDICATED performance hint, guest checks this feature bit
>     to determine if they run on dedicated vCPUs, allowing optimizations such
>     as usage of qspinlocks.
>
> Sorry for not including a "Fixes:" tag in the commit message.  If
> you think it's worth it, I can redo the pull request with it.

No, that's fine. I'm just checking that we're all on the same page
about the level of fix that goes into a late-stage rc. Particularly
as we get past rc2 or so, it's definitely helpful to me if pull
request cover letters include justifications for why the changes
should go in.

thanks
-- PMM