vfio/type1: Remove map_try_harder() code path

The AMD IOMMU driver can now map a huge-page where smaller
mappings existed before, so this code-path is no longer
triggered.

Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index d9fd3188615dc66267ba5ff715388f27356164b0..7651cfb14836ab3d751b770797fd3c7e3b985bb2 100644 (file)
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -978,32 +978,6 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
        return ret;
 }
 
-/*
- * Turns out AMD IOMMU has a page table bug where it won't map large pages
- * to a region that previously mapped smaller pages.  This should be fixed
- * soon, so this is just a temporary workaround to break mappings down into
- * PAGE_SIZE.  Better to map smaller pages than nothing.
- */
-static int map_try_harder(struct vfio_domain *domain, dma_addr_t iova,
-                         unsigned long pfn, long npage, int prot)
-{
-       long i;
-       int ret = 0;
-
-       for (i = 0; i < npage; i++, pfn++, iova += PAGE_SIZE) {
-               ret = iommu_map(domain->domain, iova,
-                               (phys_addr_t)pfn << PAGE_SHIFT,
-                               PAGE_SIZE, prot | domain->prot);
-               if (ret)
-                       break;
-       }
-
-       for (; i < npage && i > 0; i--, iova -= PAGE_SIZE)
-               iommu_unmap(domain->domain, iova, PAGE_SIZE);
-
-       return ret;
-}
-
 static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova,
                          unsigned long pfn, long npage, int prot)
 {
@@ -1013,11 +987,8 @@ static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova,
        list_for_each_entry(d, &iommu->domain_list, next) {
                ret = iommu_map(d->domain, iova, (phys_addr_t)pfn << PAGE_SHIFT,
                                npage << PAGE_SHIFT, prot | d->prot);
-               if (ret) {
-                       if (ret != -EBUSY ||
-                           map_try_harder(d, iova, pfn, npage, prot))
-                               goto unwind;
-               }
+               if (ret)
+                       goto unwind;
 
                cond_resched();
        }