Re: [Xen-devel] [PATCH v4 6/6] x86/microcode: Synchronize late microcode loading

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Tue, Jan 15, 2019 at 03:24:31PM +0000, Andrew Cooper wrote:
> On 30/11/2018 09:01, Chao Gao wrote:
> > On Thu, Nov 29, 2018 at 10:56:53AM +0100, Roger Pau Monné wrote:
> >> On Thu, Nov 29, 2018 at 12:43:25PM +0800, Chao Gao wrote:
> >>> On Wed, Nov 28, 2018 at 04:22:09PM +0100, Roger Pau Monné wrote:
> >>>> On Wed, Nov 28, 2018 at 01:34:16PM +0800, Chao Gao wrote:
> >>>>> This patch ports microcode improvement patches from linux kernel.
> >>>>>
> >>>>> Before you read any further: the early loading method is still the
> >>>>> preferred one and you should always do that. The following patch is
> >>>>> improving the late loading mechanism for long running jobs and cloud use
> >>>>> cases.
> >>>>>
> >>>>> Gather all cores and serialize the microcode update on them by doing it
> >>>>> one-by-one to make the late update process as reliable as possible and
> >>>>> avoid potential issues caused by the microcode update.
> >>>>>
> >>>>> Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
> >>>>> Tested-by: Chao Gao <chao.gao@xxxxxxxxx>
> >>>>> [linux commit: a5321aec6412b20b5ad15db2d6b916c05349dbff]
> >>>>> [linux commit: bb8c13d61a629276a162c1d2b1a20a815cbcfbb7]
> >>>> If this patch is the squash of two Linux commits, please post the
> >>>> ported versions of the two commits separately.
> >>> I don't understand this one.
> >> You reference two Linux commits above, why is this done?
> >>
> >> I assume this is because you are porting two Linux commits to Xen, in
> >> which case I think that should be done in two different patches, or a
> >> note needs to be added to why you merge two Linux commits into a
> >> single Xen patch.
> > The latter fixed a severe bug introduced the first one. Maybe I need
> > to add a note to clarify this.
> 
> That is fine.  Given that there is a large divergence between the Linux
> and Xen code, I would recommend not trying to port the Linux changes
> patch for patch.
> 
> This patch is fine in this form, IMO.

Sorry, somehow this slipped through the cracks and I didn't reply. I
agree it's fine as a single commit since it doesn't make any sense to
commit something with a know bug that's fixed by the next commit.

Thanks, Roger.

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