iommu: Introduce IOMMU emulation infrastructure
This patch adds the basic infrastructure necessary to emulate an IOMMU
visible to the guest. The DMAContext structure is extended with
information and a callback describing the translation, and the various
DMA functions used by devices will now perform IOMMU translation using
this callback.
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/dma.h b/dma.h
index e93076a..f52a656 100644
--- a/dma.h
+++ b/dma.h
@@ -31,28 +31,74 @@
};
#if defined(TARGET_PHYS_ADDR_BITS)
-typedef target_phys_addr_t dma_addr_t;
-#define DMA_ADDR_BITS TARGET_PHYS_ADDR_BITS
-#define DMA_ADDR_FMT TARGET_FMT_plx
+/*
+ * When an IOMMU is present, bus addresses become distinct from
+ * CPU/memory physical addresses and may be a different size. Because
+ * the IOVA size depends more on the bus than on the platform, we more
+ * or less have to treat these as 64-bit always to cover all (or at
+ * least most) cases.
+ */
+typedef uint64_t dma_addr_t;
+
+#define DMA_ADDR_BITS 64
+#define DMA_ADDR_FMT "%" PRIx64
+
+typedef int DMATranslateFunc(DMAContext *dma,
+ dma_addr_t addr,
+ target_phys_addr_t *paddr,
+ target_phys_addr_t *len,
+ DMADirection dir);
+typedef void* DMAMapFunc(DMAContext *dma,
+ dma_addr_t addr,
+ dma_addr_t *len,
+ DMADirection dir);
+typedef void DMAUnmapFunc(DMAContext *dma,
+ void *buffer,
+ dma_addr_t len,
+ DMADirection dir,
+ dma_addr_t access_len);
+
+struct DMAContext {
+ DMATranslateFunc *translate;
+ DMAMapFunc *map;
+ DMAUnmapFunc *unmap;
+};
+
+static inline bool dma_has_iommu(DMAContext *dma)
+{
+ return !!dma;
+}
/* Checks that the given range of addresses is valid for DMA. This is
* useful for certain cases, but usually you should just use
* dma_memory_{read,write}() and check for errors */
-static inline bool dma_memory_valid(DMAContext *dma, dma_addr_t addr,
- dma_addr_t len, DMADirection dir)
+bool iommu_dma_memory_valid(DMAContext *dma, dma_addr_t addr, dma_addr_t len,
+ DMADirection dir);
+static inline bool dma_memory_valid(DMAContext *dma,
+ dma_addr_t addr, dma_addr_t len,
+ DMADirection dir)
{
- /* Stub version, with no iommu we assume all bus addresses are valid */
- return true;
+ if (!dma_has_iommu(dma)) {
+ return true;
+ } else {
+ return iommu_dma_memory_valid(dma, addr, len, dir);
+ }
}
+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)
{
- /* Stub version when we have no iommu support */
- cpu_physical_memory_rw(addr, buf, (target_phys_addr_t)len,
- dir == DMA_DIRECTION_FROM_DEVICE);
- return 0;
+ if (!dma_has_iommu(dma)) {
+ /* Fast-path for no IOMMU */
+ cpu_physical_memory_rw(addr, buf, len,
+ dir == DMA_DIRECTION_FROM_DEVICE);
+ return 0;
+ } else {
+ return iommu_dma_memory_rw(dma, addr, buf, len, dir);
+ }
}
static inline int dma_memory_read(DMAContext *dma, dma_addr_t addr,
@@ -68,28 +114,45 @@
DMA_DIRECTION_FROM_DEVICE);
}
+int iommu_dma_memory_set(DMAContext *dma, dma_addr_t addr, uint8_t c,
+ dma_addr_t len);
+
int dma_memory_set(DMAContext *dma, dma_addr_t addr, uint8_t c, dma_addr_t len);
+void *iommu_dma_memory_map(DMAContext *dma,
+ dma_addr_t addr, dma_addr_t *len,
+ DMADirection dir);
static inline void *dma_memory_map(DMAContext *dma,
dma_addr_t addr, dma_addr_t *len,
DMADirection dir)
{
- target_phys_addr_t xlen = *len;
- void *p;
+ if (!dma_has_iommu(dma)) {
+ target_phys_addr_t xlen = *len;
+ void *p;
- p = cpu_physical_memory_map(addr, &xlen,
- dir == DMA_DIRECTION_FROM_DEVICE);
- *len = xlen;
- return p;
+ p = cpu_physical_memory_map(addr, &xlen,
+ dir == DMA_DIRECTION_FROM_DEVICE);
+ *len = xlen;
+ return p;
+ } else {
+ return iommu_dma_memory_map(dma, addr, len, dir);
+ }
}
+void iommu_dma_memory_unmap(DMAContext *dma,
+ void *buffer, dma_addr_t len,
+ DMADirection dir, dma_addr_t access_len);
static inline void dma_memory_unmap(DMAContext *dma,
void *buffer, dma_addr_t len,
DMADirection dir, dma_addr_t access_len)
{
- return cpu_physical_memory_unmap(buffer, (target_phys_addr_t)len,
- dir == DMA_DIRECTION_FROM_DEVICE,
- access_len);
+ if (!dma_has_iommu(dma)) {
+ return cpu_physical_memory_unmap(buffer, (target_phys_addr_t)len,
+ dir == DMA_DIRECTION_FROM_DEVICE,
+ access_len);
+ } else {
+ iommu_dma_memory_unmap(dma, buffer, len, dir, access_len);
+ }
}
#define DEFINE_LDST_DMA(_lname, _sname, _bits, _end) \
@@ -130,6 +193,9 @@
#undef DEFINE_LDST_DMA
+void dma_context_init(DMAContext *dma, DMATranslateFunc translate,
+ DMAMapFunc map, DMAUnmapFunc unmap);
+
struct ScatterGatherEntry {
dma_addr_t base;
dma_addr_t len;
