From: Leon Romanovsky <leonro@nvidia.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
"mgurtovoy@nvidia.com" <mgurtovoy@nvidia.com>,
liulongfang <liulongfang@huawei.com>,
"Zengtao (B)" <prime.zeng@hisilicon.com>,
Jonathan Cameron <jonathan.cameron@huawei.com>,
"Wangzhou (B)" <wangzhou1@hisilicon.com>
Subject: Re: [PATCH v3 6/6] hisi_acc_vfio_pci: Add support for VFIO live migration
Date: Mon, 27 Sep 2021 21:30:23 +0300 [thread overview]
Message-ID: <YVINv17OEHplrpeS@unreal> (raw)
In-Reply-To: <20210927182224.GA1575668@nvidia.com>
On Mon, Sep 27, 2021 at 03:22:24PM -0300, Jason Gunthorpe wrote:
> On Mon, Sep 27, 2021 at 09:17:19PM +0300, Leon Romanovsky wrote:
>
> > > The point is to all out a different locking regime that relies on the
> > > sriov enable/disable removing the VF struct devices
> >
> > You can't avoid trylock, because this pci_get_sriov_pf_devdata() will be
> > called in VF where it already holds lock, so attempt to take PF lock
> > will cause to deadlock.
>
> My whole point is we cannot use the device_lock *at all* and a
> pci_get_sriov_pf_devdata() would not have it.
Right
>
> Instead it would have some test to confirm that the 'current' struct
> device is a VF of the 'target' struct device and thus the drvdata
> must be valid so long as the 'current' struct device hasn't completed
> remove.
I'm curious to see how can you implement it without holding VF lock.
>
> It is a completely different locking scheme than device lock. It also
> relies on the PF driver placing the sriov enable/disable 'locks' in
> the correct place relative to their drvdata's.
>
> Jason
next prev parent reply other threads:[~2021-09-27 18:30 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-15 9:50 [PATCH v3 0/6] vfio/hisilicon: add acc live migration driver Shameer Kolothum
2021-09-15 9:50 ` [PATCH v3 1/6] crypto: hisilicon/qm: Move the QM header to include/linux Shameer Kolothum
2021-09-15 12:49 ` Jason Gunthorpe
2021-09-15 9:50 ` [PATCH v3 2/6] crypto: hisilicon/qm: Move few definitions to common header Shameer Kolothum
2021-09-15 9:50 ` [PATCH v3 3/6] hisi_acc_qm: Move PCI device IDs " Shameer Kolothum
2021-09-22 15:11 ` Max Gurtovoy
2021-09-24 8:18 ` Shameerali Kolothum Thodi
2021-09-15 9:50 ` [PATCH v3 4/6] hisi-acc-vfio-pci: add new vfio_pci driver for HiSilicon ACC devices Shameer Kolothum
2021-09-15 12:51 ` Jason Gunthorpe
2021-09-15 13:35 ` Shameerali Kolothum Thodi
2021-09-15 9:50 ` [PATCH v3 5/6] hisi_acc_vfio_pci: Restrict access to VF dev BAR2 migration region Shameer Kolothum
2021-09-15 9:50 ` [PATCH v3 6/6] hisi_acc_vfio_pci: Add support for VFIO live migration Shameer Kolothum
2021-09-15 13:07 ` Jason Gunthorpe
2021-09-15 13:28 ` Shameerali Kolothum Thodi
2021-09-16 13:58 ` Jason Gunthorpe
2021-09-27 13:46 ` Shameerali Kolothum Thodi
2021-09-27 15:01 ` Jason Gunthorpe
2021-09-27 15:27 ` Shameerali Kolothum Thodi
2021-09-27 16:00 ` Leon Romanovsky
2021-09-27 16:06 ` Jason Gunthorpe
2021-09-27 18:17 ` Leon Romanovsky
2021-09-27 18:22 ` Jason Gunthorpe
2021-09-27 18:30 ` Leon Romanovsky [this message]
2021-09-27 18:32 ` Jason Gunthorpe
2021-09-29 3:57 ` [PATCH v3 0/6] vfio/hisilicon: add acc live migration driver Tian, Kevin
2021-09-29 8:34 ` Shameerali Kolothum Thodi
2021-09-29 9:05 ` Tian, Kevin
2021-09-29 9:16 ` Shameerali Kolothum Thodi
2021-09-30 0:42 ` Tian, Kevin
2021-09-30 6:34 ` Shameerali Kolothum Thodi
2021-10-15 5:53 ` Tian, Kevin
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