diff options
| author | Jean-Philippe Brucker <jean-philippe@linaro.org> | 2020-03-26 12:35:58 +0300 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2020-03-27 13:10:20 +0300 |
| commit | 39b3b3c9cac1b4a64a6e546c9faf0c1011d775d4 (patch) | |
| tree | e2790d0c80b65e2c208e83e7ecd7406f53083c05 | |
| parent | 7062af3ed2ba451029e3733d9f677c68f5ea9e77 (diff) | |
| download | linux-39b3b3c9cac1b4a64a6e546c9faf0c1011d775d4.tar.xz | |
iommu/virtio: Reject IOMMU page granule larger than PAGE_SIZE
We don't currently support IOMMUs with a page granule larger than the
system page size. The IOVA allocator has a BUG_ON() in this case, and
VFIO has a WARN_ON().
Removing these obstacles ranges doesn't seem possible without major
changes to the DMA API and VFIO. Some callers of iommu_map(), for
example, want to map multiple page-aligned regions adjacent to each
others for scatter-gather purposes. Even in simple DMA API uses, a call
to dma_map_page() would let the endpoint access neighbouring memory. And
VFIO users cannot ensure that their virtual address buffer is physically
contiguous at the IOMMU granule.
Rather than triggering the IOVA BUG_ON() on mismatched page sizes, abort
the vdomain finalise() with an error message. We could simply abort the
viommu probe(), but an upcoming extension to virtio-iommu will allow
setting different page masks for each endpoint.
Reported-by: Bharat Bhushan <bbhushan2@marvell.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Bharat Bhushan <bbhushan2@marvell.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20200326093558.2641019-4-jean-philippe@linaro.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>
| -rw-r--r-- | drivers/iommu/virtio-iommu.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c index 9d5d4c941874..1adc73d1f90a 100644 --- a/drivers/iommu/virtio-iommu.c +++ b/drivers/iommu/virtio-iommu.c @@ -607,12 +607,22 @@ static struct iommu_domain *viommu_domain_alloc(unsigned type) return &vdomain->domain; } -static int viommu_domain_finalise(struct viommu_dev *viommu, +static int viommu_domain_finalise(struct viommu_endpoint *vdev, struct iommu_domain *domain) { int ret; + unsigned long viommu_page_size; + struct viommu_dev *viommu = vdev->viommu; struct viommu_domain *vdomain = to_viommu_domain(domain); + viommu_page_size = 1UL << __ffs(viommu->pgsize_bitmap); + if (viommu_page_size > PAGE_SIZE) { + dev_err(vdev->dev, + "granule 0x%lx larger than system page size 0x%lx\n", + viommu_page_size, PAGE_SIZE); + return -EINVAL; + } + ret = ida_alloc_range(&viommu->domain_ids, viommu->first_domain, viommu->last_domain, GFP_KERNEL); if (ret < 0) @@ -659,7 +669,7 @@ static int viommu_attach_dev(struct iommu_domain *domain, struct device *dev) * Properly initialize the domain now that we know which viommu * owns it. */ - ret = viommu_domain_finalise(vdev->viommu, domain); + ret = viommu_domain_finalise(vdev, domain); } else if (vdomain->viommu != vdev->viommu) { dev_err(dev, "cannot attach to foreign vIOMMU\n"); ret = -EXDEV; |