> -----Original Message----- > From: Tian, Kevin [mailto:kevin.tian@xxxxxxxxx] > Sent: 29 September 2021 10:06 > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx>; > kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > linux-crypto@xxxxxxxxxxxxxxx > Cc: alex.williamson@xxxxxxxxxx; jgg@xxxxxxxxxx; mgurtovoy@xxxxxxxxxx; > Linuxarm <linuxarm@xxxxxxxxxx>; liulongfang <liulongfang@xxxxxxxxxx>; > Zengtao (B) <prime.zeng@xxxxxxxxxxxxx>; Jonathan Cameron > <jonathan.cameron@xxxxxxxxxx>; Wangzhou (B) > <wangzhou1@xxxxxxxxxxxxx>; He, Shaopeng <shaopeng.he@xxxxxxxxx>; Zhao, > Yan Y <yan.y.zhao@xxxxxxxxx> > Subject: RE: [PATCH v3 0/6] vfio/hisilicon: add acc live migration driver > > > From: Shameerali Kolothum Thodi > > <shameerali.kolothum.thodi@xxxxxxxxxx> > > > > Hi Kevin, > > > > > From: Tian, Kevin [mailto:kevin.tian@xxxxxxxxx] > > > Sent: 29 September 2021 04:58 > > > > > > Hi, Shameer, > > > > > > > From: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx> > > > > Sent: Wednesday, September 15, 2021 5:51 PM > > > > > > > > Hi, > > > > > > > > Thanks to the introduction of vfio_pci_core subsystem framework[0], > > > > now it is possible to provide vendor specific functionality to > > > > vfio pci devices. This series attempts to add vfio live migration > > > > support for HiSilicon ACC VF devices based on the new framework. > > > > > > > > HiSilicon ACC VF device MMIO space includes both the functional > > > > register space and migration control register space. As discussed > > > > in RFCv1[1], this may create security issues as these regions get > > > > shared between the Guest driver and the migration driver. > > > > Based on the feedback, we tried to address those concerns in > > > > this version. > > > > > > This series doesn't mention anything related to dirty page tracking. > > > Are you rely on Keqian's series for utilizing hardware iommu dirty > > > bit (e.g. SMMU HTTU)? > > > > Yes, this doesn't have dirty page tracking and the plan is to make use of > > Keqian's SMMU HTTU work to improve performance. We have done basic > > sanity testing with those patches. > > > > Do you plan to support migration w/o HTTU as the fallback option? > Generally one would expect the basic functionality ready before talking > about optimization. Yes, the plan is to get the basic live migration working and then we can optimize it with SMMU HTTU when it is available. > If not, how does userspace know that migration of a given device can > be allowed only when the iommu supports hardware dirty bit? Yes. It would be nice to have that info available I guess. But for these devices, they are integrated end point devices and the platform that supports these will have SMMUv3 with HTTU. Thanks, Shameer > Thanks > Kevin
