Re: [Qemu-devel] [PATCH 0/2] VFIO: Make 8-byte accesses atomic

[joserz@linux.vnet.ibm.com]

On Fri, Apr 21, 2017 at 12:06:15PM +0200, Paolo Bonzini wrote:
> 
> 
> On 20/04/2017 18:03, Alex Williamson wrote:
> > On Thu, 20 Apr 2017 00:19:23 -0700
> > Richard Henderson <rth@twiddle.net> wrote:
> > 
> >> On 04/19/2017 12:44 PM, Jose Ricardo Ziviani wrote:
> >>> This patchset has two patches:
> >>> [1] 8-byte writes to non-mapped MMIO are broken into pairs of 4-byte writes, this patch makes such pairs atomic.
> >>>
> >>> [2] Enable 8-byte accesses in vfio_region_write and vfio_region_read.
> >>>
> >>> Patches based on master.
> >>>
> >>> Jose Ricardo Ziviani (2):
> >>>   vfio: Set MemoryRegionOps:max_access_size and min_access_size
> >>>   vfio: enable 8-byte reads/writes to vfio
> >>>
> >>>  hw/vfio/common.c | 14 ++++++++++++++
> >>>  1 file changed, 14 insertions(+)
> >>>  
> >>
> >> I think these patches need to be squashed to be bisectable.
> > 
> > No, I think it's fine.  The point of patch 1/2 is to indicate that the
> > hardware supports 8-byte accesses, which will still be broken into 2
> > 4-byte accesses because we don't yet set the implemented width beyond
> > the default.  The important part is that the mutex will now group the 4
> > byte access pair together rather than letting them get re-ordered.
> > Patch 2/2 then implements native 8-byte access.  I appreciate them
> > being separate for this subtle nuance, but maybe I'm not seeing the
> > same issue as you.  Thanks,
> '
> I agree, the patches looks fine as is.
> 
> Paolo
> 

Hello!

Thank you all for your review but I have a quick question: is it ok for
merge? :)

Thanks