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? - Steve >> Changes in V2: >> - define a flag for unmap all instead of special range values >> - define the VFIO_UNMAP_ALL extension >> - forbid the combination of unmap-all and get-dirty-bitmap >> - unwind in unmap on vaddr error >> - add a new function to find first dma in a range instead of modifying >> an existing function >> - change names of update flags >> - fix concurrency bugs due to iommu lock being dropped >> - call down from from vfio to a new backend interface instead of up from >> driver to detect container close >> - use wait/wake instead of sleep and polling >> - refine the uapi specification >> - split patches into vfio vs type1 >> >> Changes in V3: >> - add vaddr_invalid_count to fix pin_pages race with unmap >> - refactor the wait helper functions >> - traverse dma entries more efficiently in unmap >> - check unmap flag conflicts more explicitly >> - rename some local variables and functions >> >> Steve Sistare (9): >> vfio: option to unmap all >> vfio/type1: unmap cleanup >> vfio/type1: implement unmap all >> vfio: interfaces to update vaddr >> vfio/type1: massage unmap iteration >> vfio/type1: implement interfaces to update vaddr >> vfio: iommu driver notify callback >> vfio/type1: implement notify callback >> vfio/type1: block on invalid vaddr >> >> drivers/vfio/vfio.c | 5 + >> drivers/vfio/vfio_iommu_type1.c | 251 +++++++++++++++++++++++++++++++++++----- >> include/linux/vfio.h | 5 + >> include/uapi/linux/vfio.h | 27 +++++ >> 4 files changed, 256 insertions(+), 32 deletions(-) >> >
