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Date: Wed, 28 Feb 2024 10:16:16 -0800
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Subject: Re: [PATCH v2 vfio 0/2] vfio/pds: Fix and simplify resets
To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>,
 Brett Creeley <brett.creeley@amd.com>, "jgg@ziepe.ca" <jgg@ziepe.ca>,
 "yishaih@nvidia.com" <yishaih@nvidia.com>,
 "kevin.tian@intel.com" <kevin.tian@intel.com>,
 "alex.williamson@redhat.com" <alex.williamson@redhat.com>,
 "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "shannon.nelson@amd.com" <shannon.nelson@amd.com>
References: <20240228003205.47311-1-brett.creeley@amd.com>
 <ead300c6e249429f92a4ce124fc0fd56@huawei.com>
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From: Brett Creeley <bcreeley@amd.com>
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On 2/28/2024 1:05 AM, Shameerali Kolothum Thodi wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
> 
> 
>> -----Original Message-----
>> From: Brett Creeley <brett.creeley@amd.com>
>> Sent: Wednesday, February 28, 2024 12:32 AM
>> To: jgg@ziepe.ca; yishaih@nvidia.com; Shameerali Kolothum Thodi
>> <shameerali.kolothum.thodi@huawei.com>; kevin.tian@intel.com;
>> alex.williamson@redhat.com; kvm@vger.kernel.org; linux-
>> kernel@vger.kernel.org
>> Cc: shannon.nelson@amd.com; brett.creeley@amd.com
>> Subject: [PATCH v2 vfio 0/2] vfio/pds: Fix and simplify resets
>>
>> This small series contains a fix and readability improvements for
>> resets.
>>
>> v2:
>> - Split single patch into 2 patches
>> - Improve commit messages
> 
> Just a query on the reset_done handler and the deferred_reset()
> logic in this driver. From a quick look, it doesn't look like you have
> a condition where a copy_to/from_user() is under state_mutex. So
> do you think we can get rid of the deferred_reset logic from this
> driver? Please see the discussion here,
> https://lore.kernel.org/kvm/20240220132459.GM13330@nvidia.com/
> 
> For HiSilicon, we do have the lock taken for PRE_COPY, but that needs fixing
> and then can get rid of the deferred_reset. I will sent out a patch for
> that soon.
> 
> Thanks,
> Shameer

Hi Shameer,

You are probably right that we can get rid of this logic, but the 
current 2 patch series is very simple and I would prefer to keep it that 
way. If you plan to make changes to the HiSilicon driver in the near 
future, then I can use that as a reference in enhancing the pds-vfio-pci 
driver.

Thanks,

Brett
> 
>>
>> v1:
>> https://lore.kernel.org/kvm/20240126183225.19193-1-
>> brett.creeley@amd.com/
>>
>> Brett Creeley (2):
>>    vfio/pds: Always clear the save/restore FDs on reset
>>    vfio/pds: Refactor/simplify reset logic
>>
>>   drivers/vfio/pci/pds/pci_drv.c  |  2 +-
>>   drivers/vfio/pci/pds/vfio_dev.c | 14 +++++++-------
>>   drivers/vfio/pci/pds/vfio_dev.h |  7 ++++++-
>>   3 files changed, 14 insertions(+), 9 deletions(-)
>>
>> --
>> 2.17.1
>