[PATCH 2/7] pci: memory access API and IOMMU support

Eduard - Gabriel Munteanu
2010-08-29T22:10:19Z

PCI devices should access memory through pci_memory_*() instead of
cpu_physical_memory_*(). This also provides support for translation and
access checking in case an IOMMU is emulated.

Memory maps are treated as remote IOTLBs (that is, translation caches
belonging to the IOMMU-aware device itself). Clients (devices) must
provide callbacks for map invalidation in case these maps are
persistent beyond the current I/O context, e.g. AIO DMA transfers.

Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
---
hw/pci.c | 191 +++++++++++++++++++++++++++++++++++++++++++++++++++-
hw/pci.h | 69 +++++++++++++++++++
hw/pci_internals.h | 12 +++
qemu-common.h | 1 +
4 files changed, 272 insertions(+), 1 deletions(-)

diff --git a/hw/pci.c b/hw/pci.c
index 2dc1577..afcb33c 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -158,6 +158,19 @@ static void pci_device_reset(PCIDevice *dev)
pci_update_mappings(dev);
}

+static int pci_no_translate(PCIDevice *iommu,
+ PCIDevice *dev,
+ pcibus_t addr,
+ target_phys_addr_t *paddr,
+ target_phys_addr_t *len,
+ unsigned perms)
+{
+ *paddr = addr;
+ *len = -1;
+
+ return 0;
+}
+
static void pci_bus_reset(void *opaque)
{
PCIBus *bus = opaque;
@@ -220,7 +233,10 @@ void pci_bus_new_inplace(PCIBus *bus, DeviceState *parent,
{
qbus_create_inplace(&bus->qbus, &pci_bus_info, parent, name);
assert(PCI_FUNC(devfn_min) == 0);
- bus->devfn_min = devfn_min;
+
+ bus->devfn_min = devfn_min;
+ bus->iommu = NULL;
+ bus->translate = pci_no_translate;

/* host bridge */
QLIST_INIT(&bus->child);
@@ -1789,3 +1805,176 @@ static char *pcibus_get_dev_path(DeviceState *dev)
return strdup(path);
}

+void pci_register_iommu(PCIDevice *iommu,
+ PCITranslateFunc *translate)
+{
+ iommu->bus->iommu = iommu;
+ iommu->bus->translate = translate;
+}
+
+void pci_memory_rw(PCIDevice *dev,
+ pcibus_t addr,
+ uint8_t *buf,
+ pcibus_t len,
+ int is_write)
+{
+ int err;
+ unsigned perms;
+ PCIDevice *iommu = dev->bus->iommu;
+ target_phys_addr_t paddr, plen;
+
+ perms = is_write ? IOMMU_PERM_WRITE : IOMMU_PERM_READ;
+
+ while (len) {
+ err = dev->bus->translate(iommu, dev, addr, &paddr, &plen, perms);
+ 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;
+ }
+}
+
+static void pci_memory_register_map(PCIDevice *dev,
+ pcibus_t addr,
+ pcibus_t len,
+ target_phys_addr_t paddr,
+ PCIInvalidateMapFunc *invalidate,
+ void *invalidate_opaque)
+{
+ PCIMemoryMap *map;
+
+ map = qemu_malloc(sizeof(PCIMemoryMap));
+ map->addr = addr;
+ map->len = len;
+ map->paddr = paddr;
+ map->invalidate = invalidate;
+ map->invalidate_opaque = invalidate_opaque;
+
+ QLIST_INSERT_HEAD(&dev->memory_maps, map, list);
+}
+
+static void pci_memory_unregister_map(PCIDevice *dev,
+ target_phys_addr_t paddr,
+ target_phys_addr_t len)
+{
+ PCIMemoryMap *map;
+
+ QLIST_FOREACH(map, &dev->memory_maps, list) {
+ if (map->paddr == paddr && map->len == len) {
+ QLIST_REMOVE(map, list);
+ free(map);
+ }
+ }
+}
+
+void pci_memory_invalidate_range(PCIDevice *dev,
+ pcibus_t addr,
+ pcibus_t len)
+{
+ PCIMemoryMap *map;
+
+ QLIST_FOREACH(map, &dev->memory_maps, list) {
+ if (ranges_overlap(addr, len, map->addr, map->len)) {
+ map->invalidate(map->invalidate_opaque);
+ QLIST_REMOVE(map, list);
+ free(map);
+ }
+ }
+}
+
+void *pci_memory_map(PCIDevice *dev,
+ PCIInvalidateMapFunc *cb,
+ void *opaque,
+ pcibus_t addr,
+ target_phys_addr_t *len,
+ int is_write)
+{
+ int err;
+ unsigned perms;
+ PCIDevice *iommu = dev->bus->iommu;
+ target_phys_addr_t paddr, plen;
+
+ perms = is_write ? IOMMU_PERM_WRITE : IOMMU_PERM_READ;
+
+ plen = *len;
+ err = dev->bus->translate(iommu, dev, addr, &paddr, &plen, perms);
+ 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;
+ }
+
+ /* We treat maps as remote TLBs to cope with stuff like AIO. */
+ if (cb) {
+ pci_memory_register_map(dev, addr, *len, paddr, cb, opaque);
+ }
+
+ return cpu_physical_memory_map(paddr, len, is_write);
+}
+
+void pci_memory_unmap(PCIDevice *dev,
+ void *buffer,
+ target_phys_addr_t len,
+ int is_write,
+ target_phys_addr_t access_len)
+{
+ cpu_physical_memory_unmap(buffer, len, is_write, access_len);
+ pci_memory_unregister_map(dev, (target_phys_addr_t) buffer, len);
+}
+
+#define DEFINE_PCI_LD(suffix, size) \
+uint##size##_t pci_ld##suffix(PCIDevice *dev, pcibus_t addr) \
+{ \
+ int err; \
+ target_phys_addr_t paddr, plen; \
+ \
+ err = dev->bus->translate(dev->bus->iommu, dev, \
+ addr, &paddr, &plen, IOMMU_PERM_READ); \
+ if (err || (plen < size / 8)) { \
+ return 0; \
+ } \
+ \
+ return ld##suffix##_phys(paddr); \
+}
+
+#define DEFINE_PCI_ST(suffix, size) \
+void pci_st##suffix(PCIDevice *dev, pcibus_t addr, uint##size##_t val) \
+{ \
+ int err; \
+ target_phys_addr_t paddr, plen; \
+ \
+ err = dev->bus->translate(dev->bus->iommu, dev, \
+ addr, &paddr, &plen, IOMMU_PERM_WRITE); \
+ if (err || (plen < size / 8)) { \
+ return; \
+ } \
+ \
+ st##suffix##_phys(paddr, val); \
+}
+
+DEFINE_PCI_LD(ub, 8)
+DEFINE_PCI_LD(uw, 16)
+DEFINE_PCI_LD(l, 32)
+DEFINE_PCI_LD(q, 64)
+
+DEFINE_PCI_ST(b, 8)
+DEFINE_PCI_ST(w, 16)
+DEFINE_PCI_ST(l, 32)
+DEFINE_PCI_ST(q, 64)
diff --git a/hw/pci.h b/hw/pci.h
index c551f96..c95863a 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -172,6 +172,8 @@ struct PCIDevice {
char *romfile;
ram_addr_t rom_offset;
uint32_t rom_bar;
+
+ QLIST_HEAD(, PCIMemoryMap) memory_maps;
};

PCIDevice *pci_register_device(PCIBus *bus, const char *name,
@@ -391,4 +393,71 @@ static inline int ranges_overlap(uint64_t first1, uint64_t len1,
return !(last2 < first1 || last1 < first2);
}

+/*
+ * Memory I/O and PCI IOMMU definitions.
+ */
+
+#define IOMMU_PERM_READ (1 << 0)
+#define IOMMU_PERM_WRITE (1 << 1)
+#define IOMMU_PERM_RW (IOMMU_PERM_READ | IOMMU_PERM_WRITE)
+
+typedef int PCIInvalidateMapFunc(void *opaque);
+typedef int PCITranslateFunc(PCIDevice *iommu,
+ PCIDevice *dev,
+ pcibus_t addr,
+ target_phys_addr_t *paddr,
+ target_phys_addr_t *len,
+ unsigned perms);
+
+void pci_memory_rw(PCIDevice *dev,
+ pcibus_t addr,
+ uint8_t *buf,
+ pcibus_t len,
+ int is_write);
+void *pci_memory_map(PCIDevice *dev,
+ PCIInvalidateMapFunc *cb,
+ void *opaque,
+ pcibus_t addr,
+ target_phys_addr_t *len,
+ int is_write);
+void pci_memory_unmap(PCIDevice *dev,
+ void *buffer,
+ target_phys_addr_t len,
+ int is_write,
+ target_phys_addr_t access_len);
+void pci_register_iommu(PCIDevice *dev, PCITranslateFunc *translate);
+void pci_memory_invalidate_range(PCIDevice *dev, pcibus_t addr, pcibus_t len);
+
+#define DECLARE_PCI_LD(suffix, size) \
+uint##size##_t pci_ld##suffix(PCIDevice *dev, pcibus_t addr);
+
+#define DECLARE_PCI_ST(suffix, size) \
+void pci_st##suffix(PCIDevice *dev, pcibus_t addr, uint##size##_t val);
+
+DECLARE_PCI_LD(ub, 8)
+DECLARE_PCI_LD(uw, 16)
+DECLARE_PCI_LD(l, 32)
+DECLARE_PCI_LD(q, 64)
+
+DECLARE_PCI_ST(b, 8)
+DECLARE_PCI_ST(w, 16)
+DECLARE_PCI_ST(l, 32)
+DECLARE_PCI_ST(q, 64)
+
+static inline void pci_memory_read(PCIDevice *dev,
+ pcibus_t addr,
+ uint8_t *buf,
+ pcibus_t len)
+{
+ pci_memory_rw(dev, addr, buf, len, 0);
+}
+
+static inline void pci_memory_write(PCIDevice *dev,
+ pcibus_t addr,
+ const uint8_t *buf,
+ pcibus_t len)
+{
+ pci_memory_rw(dev, addr, (uint8_t *) buf, len, 1);
+}
+
#endif
diff --git a/hw/pci_internals.h b/hw/pci_internals.h
index e3c93a3..fb134b9 100644
--- a/hw/pci_internals.h
+++ b/hw/pci_internals.h
@@ -33,6 +33,9 @@ struct PCIBus {
Keep a count of the number of devices with raised IRQs. */
int nirq;
int *irq_count;
+
+ PCIDevice *iommu;
+ PCITranslateFunc *translate;
};

struct PCIBridge {
@@ -44,4 +47,13 @@ struct PCIBridge {
const char *bus_name;
};

+struct PCIMemoryMap {
+ pcibus_t addr;
+ pcibus_t len;
+ target_phys_addr_t paddr;
+ PCIInvalidateMapFunc *invalidate;
+ void *invalidate_opaque;
+ QLIST_ENTRY(PCIMemoryMap) list;
+};
+
#endif /* QEMU_PCI_INTERNALS_H */
diff --git a/qemu-common.h b/qemu-common.h
index d735235..8b060e8 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -218,6 +218,7 @@ typedef struct SMBusDevice SMBusDevice;
typedef struct PCIHostState PCIHostState;
typedef struct PCIExpressHost PCIExpressHost;
typedef struct PCIBus PCIBus;
+typedef struct PCIMemoryMap PCIMemoryMap;
typedef struct PCIDevice PCIDevice;
typedef struct PCIBridge PCIBridge;
typedef struct SerialState SerialState;
--
1.7.1