diff options
Diffstat (limited to 'dma.h')
| -rw-r--r-- | dma.h | 53 |
1 files changed, 51 insertions, 2 deletions
@@ -13,6 +13,7 @@ #include <stdio.h> #include "hw/hw.h" #include "block.h" +#include "kvm.h" typedef struct DMAContext DMAContext; typedef struct ScatterGatherEntry ScatterGatherEntry; @@ -65,6 +66,31 @@ struct DMAContext { DMAUnmapFunc *unmap; }; +static inline void dma_barrier(DMAContext *dma, DMADirection dir) +{ + /* + * This is called before DMA read and write operations + * unless the _relaxed form is used and is responsible + * for providing some sane ordering of accesses vs + * concurrently running VCPUs. + * + * Users of map(), unmap() or lower level st/ld_* + * operations are responsible for providing their own + * ordering via barriers. + * + * This primitive implementation does a simple smp_mb() + * before each operation which provides pretty much full + * ordering. + * + * A smarter implementation can be devised if needed to + * use lighter barriers based on the direction of the + * transfer, the DMA context, etc... + */ + if (kvm_enabled()) { + smp_mb(); + } +} + static inline bool dma_has_iommu(DMAContext *dma) { return !!dma; @@ -88,8 +114,9 @@ static inline bool dma_memory_valid(DMAContext *dma, int iommu_dma_memory_rw(DMAContext *dma, dma_addr_t addr, void *buf, dma_addr_t len, DMADirection dir); -static inline int dma_memory_rw(DMAContext *dma, dma_addr_t addr, - void *buf, dma_addr_t len, DMADirection dir) +static inline int dma_memory_rw_relaxed(DMAContext *dma, dma_addr_t addr, + void *buf, dma_addr_t len, + DMADirection dir) { if (!dma_has_iommu(dma)) { /* Fast-path for no IOMMU */ @@ -101,6 +128,28 @@ static inline int dma_memory_rw(DMAContext *dma, dma_addr_t addr, } } +static inline int dma_memory_read_relaxed(DMAContext *dma, dma_addr_t addr, + void *buf, dma_addr_t len) +{ + return dma_memory_rw_relaxed(dma, addr, buf, len, DMA_DIRECTION_TO_DEVICE); +} + +static inline int dma_memory_write_relaxed(DMAContext *dma, dma_addr_t addr, + const void *buf, dma_addr_t len) +{ + return dma_memory_rw_relaxed(dma, addr, (void *)buf, len, + DMA_DIRECTION_FROM_DEVICE); +} + +static inline int dma_memory_rw(DMAContext *dma, dma_addr_t addr, + void *buf, dma_addr_t len, + DMADirection dir) +{ + dma_barrier(dma, dir); + + return dma_memory_rw_relaxed(dma, addr, buf, len, dir); +} + static inline int dma_memory_read(DMAContext *dma, dma_addr_t addr, void *buf, dma_addr_t len) { |