From: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: "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>,
Linuxarm <linuxarm@huawei.com>,
liulongfang <liulongfang@huawei.com>,
"Zengtao (B)" <prime.zeng@hisilicon.com>,
yuzenghui <yuzenghui@huawei.com>,
"Jonathan Cameron" <jonathan.cameron@huawei.com>,
"Wangzhou (B)" <wangzhou1@hisilicon.com>
Subject: RE: [RFC v2 0/4] vfio/hisilicon: add acc live migration driver
Date: Wed, 2 Feb 2022 16:10:06 +0000 [thread overview]
Message-ID: <c8a0731c589e49068a78afcc73d66bfa@huawei.com> (raw)
In-Reply-To: <20220202153945.GT1786498@nvidia.com>
> -----Original Message-----
> From: Jason Gunthorpe [mailto:jgg@nvidia.com]
> Sent: 02 February 2022 15:40
> To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
> Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-crypto@vger.kernel.org; alex.williamson@redhat.com;
> mgurtovoy@nvidia.com; Linuxarm <linuxarm@huawei.com>; liulongfang
> <liulongfang@huawei.com>; Zengtao (B) <prime.zeng@hisilicon.com>;
> yuzenghui <yuzenghui@huawei.com>; Jonathan Cameron
> <jonathan.cameron@huawei.com>; Wangzhou (B) <wangzhou1@hisilicon.com>
> Subject: Re: [RFC v2 0/4] vfio/hisilicon: add acc live migration driver
>
> On Wed, Feb 02, 2022 at 02:34:52PM +0000, Shameerali Kolothum Thodi
> wrote:
>
> > > There are few topics to consider:
> > > - Which of the three feature sets (STOP_COPY, P2P and PRECOPY) make
> > > sense for this driver?
> >
> > I think it will be STOP_COPY only for now. We might have PRECOPY
> > feature once we have the SMMUv3 HTTU support in future.
>
> HTTU is the dirty tracking feature? To be clear VFIO migration support for
> PRECOPY has nothing to do with IOMMU based dirty page tracking.
Yes, it is based on the IOMMU hardware dirty bit management support.
A RFC was posted sometime back,
https://lore.kernel.org/kvm/20210507103608.39440-1-zhukeqian1@huawei.com/
Ok, my guess was that the PRECOPY here was related. Thanks for clarifying.
>
> > > - I think we discussed the P2P implementation and decided it would
> > > work for this device? Can you re-read and confirm?
> >
> > In our case these devices are Integrated End Point devices and doesn't
> > have P2P DMA capability. Hence the FSM arcs will be limited to
> > STOP_COPY feature I guess. Also, since we cannot guarantee a NDMA
> > state in STOP, my assumption currently is the onus of making sure that
> > no MMIO access happens in STOP is on the user. Is that a valid assumption?
>
> Yes, you can treat RUNNING_P2P as the same as STOP and rely on no MMIO
> access to sustain it.
Ok.
> (and I'm wondering sometimes if we should rename RUNNING_P2P to
> STOP_P2P - ie the device is stopped but still allows inbound P2P to make this
> clearer)
>
> > Do we need to set the below before the feature query?
> > Or am I using a wrong Qemu/kernel repo?
> >
> > +++ b/hw/vfio/migration.c
> > @@ -488,6 +488,7 @@ static int vfio_migration_query_flags(VFIODevice
> > *vbasedev, uint64_t *mig_flags)
> > struct vfio_device_feature_migration *mig = (void
> > *)feature->data;
> >
> > feature->argsz = sizeof(buf);
> > + feature->flags = VFIO_DEVICE_FEATURE_MIGRATION |
> > + VFIO_DEVICE_FEATURE_GET;
> > if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature) != 0)
> > return -EOPNOTSUPP;
>
> Oh, this is my mistake I thought this got pushed to that github already but
> didn't, I updated it.
Ok. Thanks.
> If you have a prototype can you post another RFC?
Sure, will do. I just started and has only a skeleton proto based on v2 now.
Will send out a RFC soon once I have all the FSM arcs implemented
and sanity tested.
Thanks,
Shameer
next prev parent reply other threads:[~2022-02-02 16:10 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-02 9:58 [RFC v2 0/4] vfio/hisilicon: add acc live migration driver Shameer Kolothum
2021-07-02 9:58 ` [RFC v2 1/4] hisi-acc-vfio-pci: add new vfio_pci driver for HiSilicon ACC devices Shameer Kolothum
2021-07-02 20:29 ` Alex Williamson
2021-07-05 7:20 ` Shameerali Kolothum Thodi
2021-07-04 7:03 ` Leon Romanovsky
2021-07-05 8:47 ` Shameerali Kolothum Thodi
2021-07-05 9:41 ` Max Gurtovoy
2021-07-05 10:18 ` Shameerali Kolothum Thodi
2021-07-05 18:27 ` Leon Romanovsky
2021-07-05 18:32 ` Jason Gunthorpe
2021-07-06 3:59 ` Leon Romanovsky
2021-07-06 4:39 ` Christoph Hellwig
2021-07-06 11:51 ` Jason Gunthorpe
2021-07-02 9:58 ` [RFC v2 2/4] hisi_acc_vfio_pci: Override ioctl method to limit BAR2 region size Shameer Kolothum
2021-07-02 20:29 ` Alex Williamson
2021-07-05 7:22 ` Shameerali Kolothum Thodi
2021-07-02 9:58 ` [RFC v2 3/4] crypto: hisilicon/qm - Export mailbox functions for common use Shameer Kolothum
2021-07-04 9:34 ` Max Gurtovoy
2021-07-05 10:23 ` Shameerali Kolothum Thodi
2021-07-02 9:58 ` [RFC v2 4/4] hisi_acc_vfio_pci: Add support for vfio live migration Shameer Kolothum
2022-02-02 13:14 ` [RFC v2 0/4] vfio/hisilicon: add acc live migration driver Jason Gunthorpe
2022-02-02 14:34 ` Shameerali Kolothum Thodi
2022-02-02 15:39 ` Jason Gunthorpe
2022-02-02 16:10 ` Shameerali Kolothum Thodi [this message]
2022-02-02 17:03 ` Jason Gunthorpe
2022-02-02 19:05 ` Joao Martins
2022-02-03 15:18 ` Jason Gunthorpe
2022-02-04 19:53 ` Joao Martins
2022-02-04 23:07 ` Jason Gunthorpe
2022-02-11 17:28 ` Joao Martins
2022-02-11 17:49 ` Jason Gunthorpe
2022-02-11 21:43 ` Joao Martins
2022-02-12 0:01 ` Jason Gunthorpe
2022-02-14 13:34 ` Joao Martins
2022-02-14 14:06 ` Jason Gunthorpe
2022-02-15 16:00 ` Joao Martins
2022-02-15 16:21 ` Jason Gunthorpe
2022-02-22 11:55 ` Joao Martins
2022-02-23 1:03 ` Jason Gunthorpe
2022-02-25 19:18 ` Joao Martins
2022-02-25 20:44 ` Jason Gunthorpe
2022-02-28 13:01 ` Joao Martins
2022-02-28 21:01 ` Jason Gunthorpe
2022-03-01 13:06 ` Joao Martins
2022-03-01 13:54 ` Jason Gunthorpe
2022-03-01 14:27 ` Joao Martins
2022-03-11 13:51 ` iommufd(+vfio-compat) dirty tracking (Was: Re: [RFC v2 0/4] vfio/hisilicon: add acc live migration driver) Joao Martins
2022-03-15 19:29 ` Jason Gunthorpe
2022-03-16 16:36 ` iommufd(+vfio-compat) dirty tracking Joao Martins
2022-03-16 20:37 ` Joao Martins
2022-03-18 17:12 ` Joao Martins
2022-03-18 17:34 ` Jason Gunthorpe
2022-02-02 17:30 ` [RFC v2 0/4] vfio/hisilicon: add acc live migration driver Alex Williamson
2022-02-02 18:04 ` Jason Gunthorpe
2022-02-18 16:37 ` Jason Gunthorpe
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