qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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


From: Paolo Bonzini
Subject: Re: [Qemu-devel] [PATCH 0/2] VFIO: Make 8-byte accesses atomic
Date: Fri, 21 Apr 2017 12:06:15 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0


On 20/04/2017 18:03, Alex Williamson wrote:
> On Thu, 20 Apr 2017 00:19:23 -0700
> Richard Henderson <address@hidden> 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



reply via email to

[Prev in Thread] Current Thread [Next in Thread]