From: Nadav Amit namit@vmware.com
[ Upstream commit 3b122a5666cb7c0bb9a439fba0c9a6cf59f999c3 ]
On virtual machines, software must flush the IOTLB after each page table entry update.
The iommu_map_sg() code iterates through the given scatter-gather list and invokes iommu_map() for each element in the scatter-gather list, which calls into the vendor IOMMU driver through iommu_ops callback. As the result, a single sg mapping may lead to multiple IOTLB flushes.
Fix this by adding amd_iotlb_sync_map() callback and flushing at this point after all sg mappings we set.
This commit is followed and inspired by commit 933fcd01e97e2 ("iommu/vt-d: Add iotlb_sync_map callback").
Cc: Joerg Roedel joro@8bytes.org Cc: Will Deacon will@kernel.org Cc: Jiajun Cao caojiajun@vmware.com Cc: Robin Murphy robin.murphy@arm.com Cc: Lu Baolu baolu.lu@linux.intel.com Cc: iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Nadav Amit namit@vmware.com Link: https://lore.kernel.org/r/20210723093209.714328-7-namit@vmware.com Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/amd/iommu.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index 69d441fc1e32..d11386177301 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -2028,6 +2028,16 @@ static int amd_iommu_attach_device(struct iommu_domain *dom, return ret; }
+static void amd_iommu_iotlb_sync_map(struct iommu_domain *dom, + unsigned long iova, size_t size) +{ + struct protection_domain *domain = to_pdomain(dom); + struct io_pgtable_ops *ops = &domain->iop.iop.ops; + + if (ops->map) + domain_flush_np_cache(domain, iova, size); +} + static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova, phys_addr_t paddr, size_t page_size, int iommu_prot, gfp_t gfp) @@ -2046,10 +2056,8 @@ static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova, if (iommu_prot & IOMMU_WRITE) prot |= IOMMU_PROT_IW;
- if (ops->map) { + if (ops->map) ret = ops->map(ops, iova, paddr, page_size, prot, gfp); - domain_flush_np_cache(domain, iova, page_size); - }
return ret; } @@ -2197,6 +2205,7 @@ const struct iommu_ops amd_iommu_ops = { .attach_dev = amd_iommu_attach_device, .detach_dev = amd_iommu_detach_device, .map = amd_iommu_map, + .iotlb_sync_map = amd_iommu_iotlb_sync_map, .unmap = amd_iommu_unmap, .iova_to_phys = amd_iommu_iova_to_phys, .probe_device = amd_iommu_probe_device,