intel-iommu: Fix intel_iommu_unmap_range() with size 0

After some API change, intel_iommu_unmap_range() introduced a assumption that
parameter size != 0, otherwise the dma_pte_clean_range() would have a
overflowed argument. But the user like KVM don't have this assumption before,
then some BUG() triggered.

Fix it by ignoring size = 0.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 360fb67..ebc9b8d 100644 (file)
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -3600,6 +3600,9 @@ static void intel_iommu_unmap_range(struct iommu_domain *domain,
 {
        struct dmar_domain *dmar_domain = domain->priv;
 
 {
        struct dmar_domain *dmar_domain = domain->priv;
 

+       if (!size)
+               return;
+

        dma_pte_clear_range(dmar_domain, iova >> VTD_PAGE_SHIFT,
                            (iova + size - 1) >> VTD_PAGE_SHIFT);
 
        dma_pte_clear_range(dmar_domain, iova >> VTD_PAGE_SHIFT,
                            (iova + size - 1) >> VTD_PAGE_SHIFT);