diff options
Diffstat (limited to 'drivers/xen/swiotlb-xen.c')
| -rw-r--r-- | drivers/xen/swiotlb-xen.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index 1eac0731c349..ebd8f218a788 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -75,14 +75,32 @@ static unsigned long xen_io_tlb_nslabs; static u64 start_dma_addr; +/* + * Both of these functions should avoid PFN_PHYS because phys_addr_t + * can be 32bit when dma_addr_t is 64bit leading to a loss in + * information if the shift is done before casting to 64bit. + */ static inline dma_addr_t xen_phys_to_bus(phys_addr_t paddr) { - return phys_to_machine(XPADDR(paddr)).maddr; + unsigned long mfn = pfn_to_mfn(PFN_DOWN(paddr)); + dma_addr_t dma = (dma_addr_t)mfn << PAGE_SHIFT; + + dma |= paddr & ~PAGE_MASK; + + return dma; } static inline phys_addr_t xen_bus_to_phys(dma_addr_t baddr) { - return machine_to_phys(XMADDR(baddr)).paddr; + unsigned long pfn = mfn_to_pfn(PFN_DOWN(baddr)); + dma_addr_t dma = (dma_addr_t)pfn << PAGE_SHIFT; + phys_addr_t paddr = dma; + + BUG_ON(paddr != dma); /* truncation has occurred, should never happen */ + + paddr |= baddr & ~PAGE_MASK; + + return paddr; } static inline dma_addr_t xen_virt_to_bus(void *address) |