diff options
| author | David Woodhouse <dwmw2@infradead.org> | 2016-09-12 10:49:11 +0800 |
|---|---|---|
| committer | David Woodhouse <dwmw2@infradead.org> | 2016-11-19 09:42:35 -0800 |
| commit | 910170442944e1f8674fd5ddbeeb8ccd1877ea98 (patch) | |
| tree | 0d3b866ec62df63888e0c747e724ccd6f4b6efdf /drivers | |
| parent | 1c387188c60f53b338c20eee32db055dfe022a9b (diff) | |
| download | linux-910170442944e1f8674fd5ddbeeb8ccd1877ea98.tar.bz2 | |
iommu/vt-d: Fix PASID table allocation
Somehow I ended up with an off-by-three error in calculating the size of
the PASID and PASID State tables, which triggers allocations failures as
those tables unfortunately have to be physically contiguous.
In fact, even the *correct* maximum size of 8MiB is problematic and is
wont to lead to allocation failures. Since I have extracted a promise
that this *will* be fixed in hardware, I'm happy to limit it on the
current hardware to a maximum of 0x20000 PASIDs, which gives us 1MiB
tables — still not ideal, but better than before.
Reported by Mika Kuoppala <mika.kuoppala@linux.intel.com> and also by
Xunlei Pang <xlpang@redhat.com> who submitted a simpler patch to fix
only the allocation (and not the free) to the "correct" limit... which
was still problematic.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iommu/intel-svm.c | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c index 8ebb3530afa7..cb72e0011310 100644 --- a/drivers/iommu/intel-svm.c +++ b/drivers/iommu/intel-svm.c @@ -39,10 +39,18 @@ int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu) struct page *pages; int order; - order = ecap_pss(iommu->ecap) + 7 - PAGE_SHIFT; - if (order < 0) - order = 0; - + /* Start at 2 because it's defined as 2^(1+PSS) */ + iommu->pasid_max = 2 << ecap_pss(iommu->ecap); + + /* Eventually I'm promised we will get a multi-level PASID table + * and it won't have to be physically contiguous. Until then, + * limit the size because 8MiB contiguous allocations can be hard + * to come by. The limit of 0x20000, which is 1MiB for each of + * the PASID and PASID-state tables, is somewhat arbitrary. */ + if (iommu->pasid_max > 0x20000) + iommu->pasid_max = 0x20000; + + order = get_order(sizeof(struct pasid_entry) * iommu->pasid_max); pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order); if (!pages) { pr_warn("IOMMU: %s: Failed to allocate PASID table\n", @@ -53,6 +61,8 @@ int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu) pr_info("%s: Allocated order %d PASID table.\n", iommu->name, order); if (ecap_dis(iommu->ecap)) { + /* Just making it explicit... */ + BUILD_BUG_ON(sizeof(struct pasid_entry) != sizeof(struct pasid_state_entry)); pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order); if (pages) iommu->pasid_state_table = page_address(pages); @@ -68,11 +78,7 @@ int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu) int intel_svm_free_pasid_tables(struct intel_iommu *iommu) { - int order; - - order = ecap_pss(iommu->ecap) + 7 - PAGE_SHIFT; - if (order < 0) - order = 0; + int order = get_order(sizeof(struct pasid_entry) * iommu->pasid_max); if (iommu->pasid_table) { free_pages((unsigned long)iommu->pasid_table, order); @@ -371,8 +377,8 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_ } svm->iommu = iommu; - if (pasid_max > 2 << ecap_pss(iommu->ecap)) - pasid_max = 2 << ecap_pss(iommu->ecap); + if (pasid_max > iommu->pasid_max) + pasid_max = iommu->pasid_max; /* Do not use PASID 0 in caching mode (virtualised IOMMU) */ ret = idr_alloc(&iommu->pasid_idr, svm, |