From: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com> 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 always issuing the IOMMU pages invalidate command when device count is zero, which is the case when detaching all the devices from the domain. Cc: Boris Ostrovsky <boris.ostrov...@oracle.com> Signed-off-by: Brijesh Singh <brijesh.si...@amd.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com> --- drivers/iommu/amd_iommu.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index 525659b88ade..ab31ba75da1b 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -1248,7 +1248,13 @@ static void __domain_flush_pages(struct protection_domain *domain, build_inv_iommu_pages(&cmd, address, size, domain->id, pde); for (i = 0; i < amd_iommu_get_num_iommus(); ++i) { - if (!domain->dev_iommu[i]) + /* + * The dev_cnt is zero when all devices are detached + * from the domain. This is the case when VFIO detaches + * all devices from the group before flushing IOMMU pages. + * So, always issue the flush command. + */ + if (domain->dev_cnt && !domain->dev_iommu[i]) continue; /* -- 2.17.1