[RFC PATCH 01/13] Generic DMA memory access interface

Eduard - Gabriel Munteanu
2011-06-01T01:38:51Z

This introduces replacements for memory access functions like
cpu_physical_memory_read(). The new interface can handle address
translation and access checking through an IOMMU.

Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
---
Makefile.target | 2 +-
hw/dma_rw.c | 155 +++++++++++++++++++++++++++++++++++++++
hw/dma_rw.h | 217 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 373 insertions(+), 1 deletions(-)
create mode 100644 hw/dma_rw.c
create mode 100644 hw/dma_rw.h

diff --git a/Makefile.target b/Makefile.target
index 21f864a..ee0c80d 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -224,7 +224,7 @@ obj-i386-y += cirrus_vga.o apic.o ioapic.o piix_pci.o
obj-i386-y += vmport.o
obj-i386-y += device-hotplug.o pci-hotplug.o smbios.o wdt_ib700.o
obj-i386-y += debugcon.o multiboot.o
-obj-i386-y += pc_piix.o kvmclock.o
+obj-i386-y += pc_piix.o kvmclock.o dma_rw.o
obj-i386-$(CONFIG_SPICE) += qxl.o qxl-logger.o qxl-render.o

# shared objects
diff --git a/hw/dma_rw.c b/hw/dma_rw.c
new file mode 100644
index 0000000..824db83
--- /dev/null
+++ b/hw/dma_rw.c
@@ -0,0 +1,155 @@
+/*
+ * Generic DMA memory access interface.
+ *
+ * Copyright (c) 2011 Eduard - Gabriel Munteanu
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "dma_rw.h"
+#include "range.h"
+
+static void dma_register_memory_map(DMADevice *dev,
+ void *buffer,
+ dma_addr_t addr,
+ dma_addr_t len,
+ DMAInvalidateMapFunc *invalidate,
+ void *invalidate_opaque)
+{
+ DMAMemoryMap *map;
+
+ map = qemu_malloc(sizeof(DMAMemoryMap));
+ map->buffer = buffer;
+ map->addr = addr;
+ map->len = len;
+ map->invalidate = invalidate;
+ map->invalidate_opaque = invalidate_opaque;
+
+ QLIST_INSERT_HEAD(&dev->mmu->memory_maps, map, list);
+}
+
+static void dma_unregister_memory_map(DMADevice *dev,
+ void *buffer,
+ dma_addr_t len)
+{
+ DMAMemoryMap *map;
+
+ QLIST_FOREACH(map, &dev->mmu->memory_maps, list) {
+ if (map->buffer == buffer && map->len == len) {
+ QLIST_REMOVE(map, list);
+ free(map);
+ }
+ }
+}
+
+void dma_invalidate_memory_range(DMADevice *dev,
+ dma_addr_t addr,
+ dma_addr_t len)
+{
+ DMAMemoryMap *map;
+
+ QLIST_FOREACH(map, &dev->mmu->memory_maps, list) {
+ if (ranges_overlap(addr, len, map->addr, map->len)) {
+ map->invalidate(map->invalidate_opaque);
+ QLIST_REMOVE(map, list);
+ free(map);
+ }
+ }
+}
+
+void *dma_memory_map(DMADevice *dev,
+ DMAInvalidateMapFunc *cb,
+ void *opaque,
+ dma_addr_t addr,
+ dma_addr_t *len,
+ int is_write)
+{
+ int err;
+ target_phys_addr_t paddr, plen;
+ void *buf;
+
+ if (!dev || !dev->mmu) {
+ return cpu_physical_memory_map(addr, len, is_write);
+ }
+
+ plen = *len;
+ err = dev->mmu->translate(dev, addr, &paddr, &plen, is_write);
+ if (err) {
+ return NULL;
+ }
+
+ /*
+ * If this is true, the virtual region is contiguous,
+ * but the translated physical region isn't. We just
+ * clamp *len, much like cpu_physical_memory_map() does.
+ */
+ if (plen < *len) {
+ *len = plen;
+ }
+
+ buf = cpu_physical_memory_map(paddr, len, is_write);
+
+ /* We treat maps as remote TLBs to cope with stuff like AIO. */
+ if (cb) {
+ dma_register_memory_map(dev, buf, addr, *len, cb, opaque);
+ }
+
+ return buf;
+}
+
+void dma_memory_unmap(DMADevice *dev,
+ void *buffer,
+ dma_addr_t len,
+ int is_write,
+ dma_addr_t access_len)
+{
+ cpu_physical_memory_unmap(buffer, len, is_write, access_len);
+ if (dev && dev->mmu) {
+ dma_unregister_memory_map(dev, buffer, len);
+ }
+}
+
+void dma_memory_rw_iommu(DMADevice *dev,
+ dma_addr_t addr,
+ void *buf,
+ dma_addr_t len,
+ int is_write)
+{
+ dma_addr_t paddr, plen;
+ int err;
+
+ while (len) {
+ err = dev->mmu->translate(dev, addr, &paddr, &plen, is_write);
+ if (err) {
+ return;
+ }
+
+ /* The translation might be valid for larger regions. */
+ if (plen > len) {
+ plen = len;
+ }
+
+ cpu_physical_memory_rw(paddr, buf, plen, is_write);
+
+ len -= plen;
+ addr += plen;
+ buf += plen;
+ }
+}
+
diff --git a/hw/dma_rw.h b/hw/dma_rw.h
new file mode 100644
index 0000000..39482cb
--- /dev/null
+++ b/hw/dma_rw.h
@@ -0,0 +1,217 @@
+#ifndef DMA_RW_H
+#define DMA_RW_H
+
+#include "qemu-common.h"
+
+typedef uint64_t dma_addr_t;
+
+typedef struct DMAMmu DMAMmu;
+typedef struct DMADevice DMADevice;
+typedef struct DMAMemoryMap DMAMemoryMap;
+
+typedef int DMATranslateFunc(DMADevice *dev,
+ dma_addr_t addr,
+ dma_addr_t *paddr,
+ dma_addr_t *len,
+ int is_write);
+
+typedef void DMAInvalidateMapFunc(void *);
+
+struct DMAMmu {
+ DeviceState *iommu;
+ DMATranslateFunc *translate;
+ QLIST_HEAD(memory_maps, DMAMemoryMap) memory_maps;
+};
+
+struct DMADevice {
+ DMAMmu *mmu;
+};
+
+struct DMAMemoryMap {
+ void *buffer;
+ dma_addr_t addr;
+ dma_addr_t len;
+ DMAInvalidateMapFunc *invalidate;
+ void *invalidate_opaque;
+
+ QLIST_ENTRY(DMAMemoryMap) list;
+};
+
+void dma_memory_rw_iommu(DMADevice *dev,
+ dma_addr_t addr,
+ void *buf,
+ dma_addr_t len,
+ int is_write);
+
+static inline void dma_memory_rw(DMADevice *dev,
+ dma_addr_t addr,
+ void *buf,
+ dma_addr_t len,
+ int is_write)
+{
+ /*
+ * Fast-path non-iommu.
+ * More importantly, makes it obvious what this function does.
+ */
+ if (!dev || !dev->mmu) {
+ cpu_physical_memory_rw(addr, buf, len, is_write);
+ return;
+ }
+
+ dma_memory_rw_iommu(dev, addr, buf, len, is_write);
+}
+
+static inline void dma_memory_read(DMADevice *dev,
+ dma_addr_t addr,
+ void *buf,
+ dma_addr_t len)
+{
+ dma_memory_rw(dev, addr, buf, len, 0);
+}
+
+static inline void dma_memory_write(DMADevice *dev,
+ dma_addr_t addr,
+ const void *buf,
+ dma_addr_t len)
+{
+ dma_memory_rw(dev, addr, (void *) buf, len, 1);
+}
+
+void *dma_memory_map(DMADevice *dev,
+ DMAInvalidateMapFunc *cb,
+ void *opaque,
+ dma_addr_t addr,
+ dma_addr_t *len,
+ int is_write);
+void dma_memory_unmap(DMADevice *dev,
+ void *buffer,
+ dma_addr_t len,
+ int is_write,
+ dma_addr_t access_len);
+
+void dma_invalidate_memory_range(DMADevice *dev,
+ dma_addr_t addr,
+ dma_addr_t len);
+
+
+/*
+ * All the following macro magic tries is to
+ * achieve some type safety and avoid duplication.
+ */
+
+#define DEFINE_DMA_LD(prefix, suffix, devtype, dmafield, size) \
+static inline uint##size##_t \
+dma_ld##suffix(DMADevice *dev, dma_addr_t addr) \
+{ \
+ int err; \
+ dma_addr_t paddr, plen; \
+ \
+ if (!dev || !dev->mmu) { \
+ return ld##suffix##_phys(addr); \
+ } \
+ \
+ err = dev->mmu->translate(dev, addr, &paddr, &plen, 0); \
+ if (err || (plen < size / 8)) { \
+ return 0; \
+ } \
+ \
+ return ld##suffix##_phys(paddr); \
+}
+
+#define DEFINE_DMA_ST(prefix, suffix, devtype, dmafield, size) \
+static inline void \
+dma_st##suffix(DMADevice *dev, dma_addr_t addr, uint##size##_t val) \
+{ \
+ int err; \
+ target_phys_addr_t paddr, plen; \
+ \
+ if (!dev || !dev->mmu) { \
+ st##suffix##_phys(addr, val); \
+ return; \
+ } \
+ err = dev->mmu->translate(dev, addr, &paddr, &plen, 1); \
+ if (err || (plen < size / 8)) { \
+ return; \
+ } \
+ \
+ st##suffix##_phys(paddr, val); \
+}
+
+#define DEFINE_DMA_MEMORY_RW(prefix, devtype, dmafield)
+#define DEFINE_DMA_MEMORY_READ(prefix, devtype, dmafield)
+#define DEFINE_DMA_MEMORY_WRITE(prefix, devtype, dmafield)
+
+#define DEFINE_DMA_OPS(prefix, devtype, dmafield) \
+ /* \
+ * FIXME: find a way to handle these: \
+ * DEFINE_DMA_LD(prefix, ub, devtype, dmafield, 8) \
+ * DEFINE_DMA_LD(prefix, uw, devtype, dmafield, 16) \
+ */ \
+ DEFINE_DMA_LD(prefix, l, devtype, dmafield, 32) \
+ DEFINE_DMA_LD(prefix, q, devtype, dmafield, 64) \
+ \
+ DEFINE_DMA_ST(prefix, b, devtype, dmafield, 8) \
+ DEFINE_DMA_ST(prefix, w, devtype, dmafield, 16) \
+ DEFINE_DMA_ST(prefix, l, devtype, dmafield, 32) \
+ DEFINE_DMA_ST(prefix, q, devtype, dmafield, 64) \
+ \
+ DEFINE_DMA_MEMORY_RW(prefix, devtype, dmafield) \
+ DEFINE_DMA_MEMORY_READ(prefix, devtype, dmafield) \
+ DEFINE_DMA_MEMORY_WRITE(prefix, devtype, dmafield)
+
+DEFINE_DMA_OPS(UNUSED, UNUSED, UNUSED)
+
+/*
+ * From here on, various bus interfaces can use DEFINE_DMA_OPS
+ * to summon their own personalized clone of the DMA interface.
+ */
+
+#undef DEFINE_DMA_LD
+#undef DEFINE_DMA_ST
+#undef DEFINE_DMA_MEMORY_RW
+#undef DEFINE_DMA_MEMORY_READ
+#undef DEFINE_DMA_MEMORY_WRITE
+
+#define DEFINE_DMA_LD(prefix, suffix, devtype, dma_field, size) \
+static inline uint##size##_t \
+prefix##_ld##suffix(devtype *dev, dma_addr_t addr) \
+{ \
+ return dma_ld##suffix(&dev->dma_field, addr); \
+}
+
+#define DEFINE_DMA_ST(prefix, suffix, devtype, dma_field, size) \
+static inline void \
+prefix##_st##suffix(devtype *dev, dma_addr_t addr, uint##size##_t val) \
+{ \
+ dma_st##suffix(&dev->dma_field, addr, val); \
+}
+
+#define DEFINE_DMA_MEMORY_RW(prefix, devtype, dmafield) \
+static inline void prefix##_memory_rw(devtype *dev, \
+ dma_addr_t addr, \
+ void *buf, \
+ dma_addr_t len, \
+ int is_write) \
+{ \
+ dma_memory_rw(&dev->dmafield, addr, buf, len, is_write); \
+}
+
+#define DEFINE_DMA_MEMORY_READ(prefix, devtype, dmafield) \
+static inline void prefix##_memory_read(devtype *dev, \
+ dma_addr_t addr, \
+ void *buf, \
+ dma_addr_t len) \
+{ \
+ dma_memory_read(&dev->dmafield, addr, buf, len); \
+}
+
+#define DEFINE_DMA_MEMORY_WRITE(prefix, devtype, dmafield) \
+static inline void prefix##_memory_write(devtype *dev, \
+ dma_addr_t addr, \
+ const void *buf, \
+ dma_addr_t len) \
+{ \
+ dma_memory_write(&dev->dmafield, addr, buf, len); \
+}
+
+#endif
--
1.7.3.4