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Re: [Qemu-block] [PATCH 0/4] block/xen_disk: legacy code removal and cle
From: |
Anthony PERARD |
Subject: |
Re: [Qemu-block] [PATCH 0/4] block/xen_disk: legacy code removal and cleanup |
Date: |
Thu, 3 May 2018 10:55:17 +0100 |
User-agent: |
Mutt/1.9.5 (2018-04-13) |
On Wed, May 02, 2018 at 05:03:09PM +0100, Paul Durrant wrote:
> > -----Original Message-----
> > From: Anthony PERARD [mailto:address@hidden
> > Sent: 02 May 2018 16:58
> > To: Paul Durrant <address@hidden>
> > Cc: address@hidden; address@hidden; qemu-
> > address@hidden; Stefano Stabellini <address@hidden>; Kevin Wolf
> > <address@hidden>; Max Reitz <address@hidden>
> > Subject: Re: [PATCH 0/4] block/xen_disk: legacy code removal and cleanup
> >
> > On Mon, Apr 30, 2018 at 01:01:35PM +0100, Paul Durrant wrote:
> > > The grant copy operation was added to libxengnttab in Xen 4.8.0 (released
> > > nearly 18 months ago) but the xen_disk PV backend QEMU is still carrying
> > > a significant amount of code purely to remain compatible with older
> > > versions of Xen.
> > >
> > > As can be inferred from the diff stats below, removing this support for
> > > older versions of Xen from QEMU reduces the size of the xen_disk source
> > by
> > > more than 350 lines (~25%). The majority of this is done in patches #1
> > > and #2. Further simplifications are made in patch #3 and then some
> > cosmetic
> > > work is done in patch #4.
> >
> > FIY, I don't like this patch series. We've been checking that QEMU
> > builds against older version. I've check that it builds against 4.5 and
> > newer.
> >
>
> Ok, I can grant copy emulation in QEMU then should it not exist for the
> particular Xen/OS combo.
>
> > Also the fact that FreeBSD doesn't have support for grant copy probably
> > mean that it is too soon to remove the compatibility code from qemu.
> >
>
> On another thread I'd already agreed to emulate grant copy in libxengnttab
> for those OS where it is not supported, but if you prefer it to be in QEMU
> I'll put it there.
Yes, I think it will be better from QEMU point of view.
Thanks,
--
Anthony PERARD