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iommu/vt-d: Fix infinite loop in free_all_cpu_cached_iovas 

Per VT-d spec Section 10.4.2 ("Capability Register"), the maximum
number of possible domains is 64K; indeed this is the maximum value
that the cap_ndoms() macro will expand to.  Since the value 65536
will not fix in a u16, the 'did' variable must be promoted to an
int, otherwise the test for < 65536 will always be true and the
loop will never end.

The symptom, in my case, was a hung machine during suspend.

Fixes: 3bd4f9112f ("iommu/vt-d: Fix overflow of iommu->domains array")
Signed-off-by: Aaron Campbell <aaron@monkey.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Aaron Campbell 2016-07-02 21:23:24 -03:00 committed by Joerg Roedel
parent a99cde438d
commit 0caa7616a6
1 changed files with 2 additions and 2 deletions
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4
drivers/iommu/intel-iommu.c
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@ -4602,13 +4602,13 @@ static void free_all_cpu_cached_iovas(unsigned int cpu)
for (i = 0; i < g_num_of_iommus; i++) {
struct intel_iommu *iommu = g_iommus[i];
struct dmar_domain *domain;
u16 did;
int did;
if (!iommu)
continue;
for (did = 0; did < cap_ndoms(iommu->cap); did++) {
domain = get_iommu_domain(iommu, did);
domain = get_iommu_domain(iommu, (u16)did);
if (!domain)
continue;