• Suravee Suthikulpanit's avatar
    iommu/amd: Fix IOMMU page flush when detach device from a domain · 9825bd94
    Suravee Suthikulpanit authored
    When a VM is terminated, the VFIO driver detaches all pass-through
    devices from VFIO domain by clearing domain id and page table root
    pointer from each device table entry (DTE), and then invalidates
    the DTE. Then, the VFIO driver unmap pages and invalidate IOMMU pages.
    
    Currently, the IOMMU driver keeps track of which IOMMU and how many
    devices are attached to the domain. When invalidate IOMMU pages,
    the driver checks if the IOMMU is still attached to the domain before
    issuing the invalidate page command.
    
    However, since VFIO has already detached all devices from the domain,
    the subsequent INVALIDATE_IOMMU_PAGES commands are being skipped as
    there is no IOMMU attached to the domain. This results in data
    corruption and could cause the PCI device to end up in indeterministic
    state.
    
    Fix this by invalidate IOMMU pages when detach a device, and
    before decrementing the per-domain device reference counts.
    
    Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
    Suggested-by: default avatarJoerg Roedel <joro@8bytes.org>
    Co-developed-by: default avatarBrijesh Singh <brijesh.singh@amd.com>
    Signed-off-by: default avatarBrijesh Singh <brijesh.singh@amd.com>
    Signed-off-by: default avatarSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
    Fixes: 6de8ad9b ('x86/amd-iommu: Make iommu_flush_pages aware of multiple IOMMUs')
    Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
    9825bd94
amd_iommu.c 105 KB