@@ -1309,6 +1309,10 @@ static unsigned long iommu_unmap_page(struct protection_domain *dom,
/* Large PTE found which maps this address */
unmap_size = PTE_PAGE_SIZE(*pte);
+
+ /* Only unmap from the first pte in the page */
+ if ((unmap_size - 1) & bus_addr)
+ break;
count = PAGE_SIZE_PTE_COUNT(unmap_size);
for (i = 0; i < count; i++)
pte[i] = 0ULL;
@@ -1318,7 +1322,7 @@ static unsigned long iommu_unmap_page(struct protection_domain *dom,
unmapped += unmap_size;
}
- BUG_ON(!is_power_of_2(unmapped));
+ BUG_ON(unmapped && !is_power_of_2(unmapped));
return unmapped;
}
This is a note to let you know that I have just added a patch titled iommu/amd: Only unmap large pages from the first pte to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 697b9239f410b5f58e398afbc3ebeb8c2bab37af Mon Sep 17 00:00:00 2001 From: Alex Williamson <alex.williamson@redhat.com> Date: Fri, 21 Jun 2013 14:33:19 -0600 Subject: [PATCH] iommu/amd: Only unmap large pages from the first pte commit 60d0ca3cfd199b6612bbbbf4999a3470dad38bb1 upstream. If we use a large mapping, the expectation is that only unmaps from the first pte in the superpage are supported. Unmaps from offsets into the superpage should fail (ie. return zero sized unmap). In the current code, unmapping from an offset clears the size of the full mapping starting from an offset. For instance, if we map a 16k physically contiguous range at IOVA 0x0 with a large page, then attempt to unmap 4k at offset 12k, 4 ptes are cleared (12k - 28k) and the unmap returns 16k unmapped. This potentially incorrectly clears valid mappings and confuses drivers like VFIO that use the unmap size to release pinned pages. Fix by refusing to unmap from offsets into the page. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Joerg Roedel <joro@8bytes.org> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/iommu/amd_iommu.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) -- 1.8.1.2