diff options
| author | Chris Wright | 2011-05-28 13:15:02 -0500 |
|---|---|---|
| committer | David Woodhouse | 2011-06-01 12:47:34 +0100 |
| commit | 8fcc5372fbac085199d84a880503ed67aba3fe49 (patch) | |
| tree | aab84e5ac18fa8028efa49e2cc47a5b97d873916 | |
| parent | 9b4554b21ed07e8556405510638171f0c787742a (diff) | |
intel-iommu: Check for identity mapping candidate using system dma mask
The identity mapping code appears to make the assumption that if the
devices dma_mask is greater than 32bits the device can use identity
mapping. But that is not true: take the case where we have a 40bit
device in a 44bit architecture. The device can potentially receive a
physical address that it will truncate and cause incorrect addresses
to be used.
Instead check to see if the device's dma_mask is large enough
to address the system's dma_mask.
Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Mike Habeck <habeck@sgi.com>
Cc: stable@kernel.org
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
| -rw-r--r-- | drivers/pci/intel-iommu.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index 4eaec2fa1369..dcf051d53b74 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -2316,8 +2316,19 @@ static int iommu_should_identity_map(struct pci_dev *pdev, int startup) * Assume that they will -- if they turn out not to be, then we can * take them out of the 1:1 domain later. */ - if (!startup) - return pdev->dma_mask > DMA_BIT_MASK(32); + if (!startup) { + /* + * If the device's dma_mask is less than the system's memory + * size then this is not a candidate for identity mapping. + */ + u64 dma_mask = pdev->dma_mask; + + if (pdev->dev.coherent_dma_mask && + pdev->dev.coherent_dma_mask < dma_mask) + dma_mask = pdev->dev.coherent_dma_mask; + + return dma_mask >= dma_get_required_mask(&pdev->dev); + } return 1; } |