On Sat, 30 Jan 2021 11:54:03 -0500 Steven Sistare <steven.sistare@xxxxxxxxxx> wrote: > On 1/29/2021 4:55 PM, Alex Williamson wrote: > > On Fri, 29 Jan 2021 08:54:03 -0800 > > Steve Sistare <steven.sistare@xxxxxxxxxx> wrote: > > > >> Add interfaces that allow the underlying memory object of an iova range > >> to be mapped to a new virtual address in the host process: > >> > >> - VFIO_DMA_UNMAP_FLAG_VADDR for VFIO_IOMMU_UNMAP_DMA > >> - VFIO_DMA_MAP_FLAG_VADDR flag for VFIO_IOMMU_MAP_DMA > >> - VFIO_UPDATE_VADDR for VFIO_CHECK_EXTENSION > >> - VFIO_DMA_UNMAP_FLAG_ALL for VFIO_IOMMU_UNMAP_DMA > >> - VFIO_UNMAP_ALL for VFIO_CHECK_EXTENSION > >> > >> Unmap-vaddr invalidates the host virtual address in an iova range and blocks > >> vfio translation of host virtual addresses, but DMA to already-mapped pages > >> continues. Map-vaddr updates the base VA and resumes translation. The > >> implementation supports iommu type1 and mediated devices. Unmap-all allows > >> all ranges to be unmapped or invalidated in a single ioctl, which simplifies > >> userland code. > >> > >> This functionality is necessary for live update, in which a host process > >> such as qemu exec's an updated version of itself, while preserving its > >> guest and vfio devices. The process blocks vfio VA translation, exec's > >> its new self, mmap's the memory object(s) underlying vfio object, updates > >> the VA, and unblocks translation. For a working example that uses these > >> new interfaces, see the QEMU patch series "[PATCH V2] Live Update" at > >> https://lore.kernel.org/qemu-devel/1609861330-129855-1-git-send-email-steven.sistare@xxxxxxxxxx > >> > >> Patches 1-3 define and implement the flag to unmap all ranges. > >> Patches 4-6 define and implement the flags to update vaddr. > >> Patches 7-9 add blocking to complete the implementation. > > > > Hi Steve, > > > > It looks pretty good to me, but I have some nit-picky comments that > > I'll follow-up with on the individual patches. However, I've made the > > changes I suggest in a branch that you can find here: > > > > git://github.com/awilliam/linux-vfio.git vaddr-v3 > > > > If the changes look ok, just send me an ack, I don't want to attribute > > something to you that you don't approve of. Thanks, > > All changes look good, thanks! > Do you need anything more from me on this patch series? Here's a new branch: git://github.com/awilliam/linux-vfio.git vaddr-v3.1 Extent of the changes are s/may not/cannot/ on patches 1 & 4 and addition of Connie's R-b for all (rebased to rc6). If there are any final comments, speak now. Thanks, Alex
