On Mon, Jun 03, 2019 at 09:16:14AM +0800, Lu Baolu wrote: > This is necessary to avoid exposing valid kernel data to any > milicious device.
malicious > > Suggested-by: Christoph Hellwig <[email protected]> > Signed-off-by: Lu Baolu <[email protected]> > --- > kernel/dma/swiotlb.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index f956f785645a..ed41eb7f6131 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -35,6 +35,7 @@ > #include <linux/scatterlist.h> > #include <linux/mem_encrypt.h> > #include <linux/set_memory.h> > +#include <linux/pci.h> > #ifdef CONFIG_DEBUG_FS > #include <linux/debugfs.h> > #endif > @@ -560,6 +561,11 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, > */ > for (i = 0; i < nslots; i++) > io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT); > + > + /* Zero out the bounce buffer if the consumer is untrusted. */ > + if (dev_is_untrusted(hwdev)) > + memset(phys_to_virt(tlb_addr), 0, alloc_size); What if the alloc_size is less than a PAGE? Should this at least have ALIGN or such? > + > if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) && > (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)) > swiotlb_bounce(orig_addr, tlb_addr, mapping_size, > DMA_TO_DEVICE); > -- > 2.17.1 > _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
