[Qemu-devel] [PATCH v2 3/5] Implement fw_cfg DMA interface

["Marc Marí" <markmb@redhat.com>]

Based on the specifications on docs/specs/fw_cfg.txt

This interface is an addon. The old interface can still be used as usual.

Based on Gerd Hoffman's initial implementation.

Signed-off-by: Marc Marí <markmb@redhat.com>
---
 hw/arm/virt.c             |   2 +-
 hw/nvram/fw_cfg.c         | 261 +++++++++++++++++++++++++++++++++++++++++++---
 include/hw/nvram/fw_cfg.h |  15 ++-
 3 files changed, 260 insertions(+), 18 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index d5a8417..b88c104 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -620,7 +620,7 @@ static void create_fw_cfg(const VirtBoardInfo *vbi)
     hwaddr size = vbi->memmap[VIRT_FW_CFG].size;
     char *nodename;
 
-    fw_cfg_init_mem_wide(base + 8, base, 8);
+    fw_cfg_init_mem_wide(base + 8, base, 8, 0, NULL);
 
     nodename = g_strdup_printf("/fw-cfg@%" PRIx64, base);
     qemu_fdt_add_subnode(vbi->fdt, nodename);
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index 88481b7..7e5ba96 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -23,6 +23,7 @@
  */
 #include "hw/hw.h"
 #include "sysemu/sysemu.h"
+#include "sysemu/dma.h"
 #include "hw/isa/isa.h"
 #include "hw/nvram/fw_cfg.h"
 #include "hw/sysbus.h"
@@ -30,7 +31,8 @@
 #include "qemu/error-report.h"
 #include "qemu/config-file.h"
 
-#define FW_CFG_SIZE 2
+#define FW_CFG_IO_SIZE 12 /* Address aligned to 4 bytes */
+#define FW_CFG_CTL_SIZE 2
 #define FW_CFG_NAME "fw_cfg"
 #define FW_CFG_PATH "/machine/" FW_CFG_NAME
 
@@ -42,6 +44,15 @@
 #define FW_CFG_IO(obj)  OBJECT_CHECK(FWCfgIoState,  (obj), TYPE_FW_CFG_IO)
 #define FW_CFG_MEM(obj) OBJECT_CHECK(FWCfgMemState, (obj), TYPE_FW_CFG_MEM)
 
+/* FW_CFG_VERSION bits */
+#define FW_CFG_VERSION      0x01
+#define FW_CFG_VERSION_DMA  0x02
+
+/* FW_CFG_DMA_CONTROL bits */
+#define FW_CFG_DMA_CTL_ERROR   0x01
+#define FW_CFG_DMA_CTL_READ    0x02
+#define FW_CFG_DMA_CTL_SKIP    0x04
+
 typedef struct FWCfgEntry {
     uint32_t len;
     uint8_t *data;
@@ -59,6 +70,10 @@ struct FWCfgState {
     uint16_t cur_entry;
     uint32_t cur_offset;
     Notifier machine_ready;
+
+    bool dma_enabled;
+    AddressSpace *dma_as;
+    dma_addr_t dma_addr;
 };
 
 struct FWCfgIoState {
@@ -75,7 +90,7 @@ struct FWCfgMemState {
     FWCfgState parent_obj;
     /*< public >*/
 
-    MemoryRegion ctl_iomem, data_iomem;
+    MemoryRegion ctl_iomem, data_iomem, dma_iomem;
     uint32_t data_width;
     MemoryRegionOps wide_data_ops;
 };
@@ -294,6 +309,142 @@ static void fw_cfg_data_mem_write(void *opaque, hwaddr addr,
     } while (i);
 }
 
+static void fw_cfg_dma_transfer(FWCfgState *s)
+{
+    dma_addr_t len;
+    uint8_t *ptr;
+    void *addr;
+    FWCfgDmaAccess dma;
+    int arch = !!(s->cur_entry & FW_CFG_ARCH_LOCAL);
+    FWCfgEntry *e = &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK];
+
+    len = sizeof(dma);
+    addr = dma_memory_map(s->dma_as, s->dma_addr, &len,
+                                DMA_DIRECTION_FROM_DEVICE);
+
+    s->dma_addr = 0;
+
+    if (!addr || !len) {
+        return;
+    }
+
+    dma.address = be64_to_cpu(*(uint64_t *)(addr +
+                    offsetof(FWCfgDmaAccess, address)));
+    dma.length = be32_to_cpu(*(uint32_t *)(addr +
+                    offsetof(FWCfgDmaAccess, length)));
+    dma.control = be32_to_cpu(*(uint32_t *)(addr +
+                    offsetof(FWCfgDmaAccess, control)));
+
+    if (dma.control & FW_CFG_DMA_CTL_ERROR) {
+        goto out;
+    }
+
+    if (!(dma.control & (FW_CFG_DMA_CTL_READ | FW_CFG_DMA_CTL_SKIP))) {
+        goto out;
+    }
+
+    while (dma.length > 0) {
+        if (s->cur_entry == FW_CFG_INVALID || !e->data ||
+                                s->cur_offset >= e->len) {
+            len = dma.length;
+
+            /* If the access is not a read access, it will be a skip access,
+             * tested before.
+             */
+            if (dma.control & FW_CFG_DMA_CTL_READ) {
+                ptr = dma_memory_map(s->dma_as, dma.address, &len,
+                                     DMA_DIRECTION_FROM_DEVICE);
+                if (!ptr || !len) {
+                    dma.control |= FW_CFG_DMA_CTL_ERROR;
+                    goto out;
+                }
+
+                memset(ptr, 0, len);
+
+                dma_memory_unmap(s->dma_as, ptr, len,
+                                 DMA_DIRECTION_FROM_DEVICE, len);
+            }
+
+        } else {
+            if (dma.length <= e->len) {
+                len = dma.length;
+            } else {
+                len = e->len;
+            }
+
+            if (e->read_callback) {
+                e->read_callback(e->callback_opaque, s->cur_offset);
+            }
+
+            /* If the access is not a read access, it will be a skip access,
+             * tested before.
+             */
+            if (dma.control & FW_CFG_DMA_CTL_READ) {
+                ptr = dma_memory_map(s->dma_as, dma.address, &len,
+                                     DMA_DIRECTION_FROM_DEVICE);
+                if (!ptr || !len) {
+                    dma.control |= FW_CFG_DMA_CTL_ERROR;
+                    goto out;
+                }
+
+                memcpy(ptr, &e->data[s->cur_offset], len);
+
+                dma_memory_unmap(s->dma_as, ptr, len,
+                                 DMA_DIRECTION_FROM_DEVICE, len);
+            }
+
+            s->cur_offset += len;
+
+        }
+
+        dma.address += len;
+        dma.length  -= len;
+        dma.control = 0;
+
+        *(uint64_t *)(addr + offsetof(FWCfgDmaAccess, address)) =
+                                                cpu_to_be64(dma.address);
+        *(uint32_t *)(addr + offsetof(FWCfgDmaAccess, length)) =
+                                                cpu_to_be32(dma.length);
+        *(uint32_t *)(addr + offsetof(FWCfgDmaAccess, control)) =
+                                                cpu_to_be32(dma.control);
+    }
+
+    trace_fw_cfg_read(s, 0);
+
+out:
+    dma_memory_unmap(s->dma_as, addr, sizeof(dma),
+                                DMA_DIRECTION_FROM_DEVICE, sizeof(dma));
+    return;
+
+}
+
+static void fw_cfg_dma_mem_write(void *opaque, hwaddr addr,
+                                 uint64_t value, unsigned size)
+{
+    FWCfgState *s = opaque;
+
+    if (size == 4) {
+        if (addr == 0) {
+            /* FWCfgDmaAccess high address */
+            s->dma_addr = (0xFFFFFFFF & value) << 32;
+        } else if (addr == 4) {
+            /* FWCfgDmaAccess low address */
+            s->dma_addr |= value;
+            fw_cfg_dma_transfer(s);
+        }
+    } else if (size == 8 && addr == 0) {
+        s->dma_addr = value;
+        fw_cfg_dma_transfer(s);
+    }
+}
+
+static bool fw_cfg_dma_mem_valid(void *opaque, hwaddr addr,
+                                  unsigned size, bool is_write)
+{
+    return is_write && ((size == 4 && (addr == 0 || addr == 4)) ||
+                        (size == 8 && addr == 0));
+}
+
 static bool fw_cfg_data_mem_valid(void *opaque, hwaddr addr,
                                   unsigned size, bool is_write)
 {
@@ -321,20 +472,35 @@ static uint64_t fw_cfg_comb_read(void *opaque, hwaddr addr,
 static void fw_cfg_comb_write(void *opaque, hwaddr addr,
                               uint64_t value, unsigned size)
 {
-    switch (size) {
+    FWCfgState *s;
+
+    switch (addr) {
+    case 0:
+        fw_cfg_select(opaque, (uint16_t)value);
+        break;
     case 1:
         fw_cfg_write(opaque, (uint8_t)value);
         break;
-    case 2:
-        fw_cfg_select(opaque, (uint16_t)value);
+    case 4:
+        /* FWCfgDmaAccess low address */
+        s = opaque;
+        s->dma_addr |= value;
+        fw_cfg_dma_transfer(s);
         break;
+    case 8:
+        /* FWCfgDmaAccess high address */
+        s = opaque;
+        s->dma_addr = (0xFFFFFFFF & value) << 32;
     }
 }
 
 static bool fw_cfg_comb_valid(void *opaque, hwaddr addr,
                                   unsigned size, bool is_write)
 {
-    return (size == 1) || (is_write && size == 2);
+    FWCfgState *s = opaque;
+
+    return (size == 1) || (is_write && size == 2) ||
+            (s->dma_enabled && is_write && addr >= 4);
 }
 
 static const MemoryRegionOps fw_cfg_ctl_mem_ops = {
@@ -361,6 +527,12 @@ static const MemoryRegionOps fw_cfg_comb_mem_ops = {
     .valid.accepts = fw_cfg_comb_valid,
 };
 
+static const MemoryRegionOps fw_cfg_dma_mem_ops = {
+    .write = fw_cfg_dma_mem_write,
+    .endianness = DEVICE_BIG_ENDIAN,
+    .valid.accepts = fw_cfg_dma_mem_valid,
+};
+
 static void fw_cfg_reset(DeviceState *d)
 {
     FWCfgState *s = FW_CFG(d);
@@ -401,6 +573,22 @@ static bool is_version_1(void *opaque, int version_id)
     return version_id == 1;
 }
 
+static bool fw_cfg_dma_enabled(void *opaque)
+{
+    FWCfgState *s = opaque;
+
+    return s->dma_enabled;
+}
+
+static VMStateDescription vmstate_fw_cfg_dma = {
+    .name = "fw_cfg/dma",
+    .needed = fw_cfg_dma_enabled,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(dma_addr, FWCfgState),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
 static const VMStateDescription vmstate_fw_cfg = {
     .name = "fw_cfg",
     .version_id = 2,
@@ -410,6 +598,10 @@ static const VMStateDescription vmstate_fw_cfg = {
         VMSTATE_UINT16_HACK(cur_offset, FWCfgState, is_version_1),
         VMSTATE_UINT32_V(cur_offset, FWCfgState, 2),
         VMSTATE_END_OF_LIST()
+    },
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_fw_cfg_dma,
+        NULL,
     }
 };
 
@@ -595,7 +787,6 @@ static void fw_cfg_init1(DeviceState *dev)
     qdev_init_nofail(dev);
 
     fw_cfg_add_bytes(s, FW_CFG_SIGNATURE, (char *)"QEMU", 4);
-    fw_cfg_add_i32(s, FW_CFG_ID, 1);
     fw_cfg_add_bytes(s, FW_CFG_UUID, qemu_uuid, 16);
     fw_cfg_add_i16(s, FW_CFG_NOGRAPHIC, (uint16_t)(display_type == DT_NOGRAPHIC));
     fw_cfg_add_i16(s, FW_CFG_NB_CPUS, (uint16_t)smp_cpus);
@@ -607,22 +798,45 @@ static void fw_cfg_init1(DeviceState *dev)
     qemu_add_machine_init_done_notifier(&s->machine_ready);
 }
 
-FWCfgState *fw_cfg_init_io(uint32_t iobase)
+FWCfgState *fw_cfg_init_io_dma(uint32_t iobase, AddressSpace *dma_as)
 {
     DeviceState *dev;
+    FWCfgState *s;
+    uint32_t version = FW_CFG_VERSION;
 
     dev = qdev_create(NULL, TYPE_FW_CFG_IO);
     qdev_prop_set_uint32(dev, "iobase", iobase);
+
     fw_cfg_init1(dev);
+    s = FW_CFG(dev);
+
+    if (dma_as) {
+        /* 64 bits for the address field */
+        s->dma_as = dma_as;
+        s->dma_enabled = true;
+        s->dma_addr = 0;
+
+        version |= FW_CFG_VERSION_DMA;
+    }
+
+    fw_cfg_add_i32(s, FW_CFG_ID, version);
 
-    return FW_CFG(dev);
+    return s;
 }
 
-FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr, hwaddr data_addr,
-                                 uint32_t data_width)
+FWCfgState *fw_cfg_init_io(uint32_t iobase)
+{
+    return fw_cfg_init_io_dma(iobase, NULL);
+}
+
+FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr,
+                                 hwaddr data_addr, uint32_t data_width,
+                                 hwaddr dma_addr, AddressSpace *dma_as)
 {
     DeviceState *dev;
     SysBusDevice *sbd;
+    FWCfgState *s;
+    uint32_t version = FW_CFG_VERSION;
 
     dev = qdev_create(NULL, TYPE_FW_CFG_MEM);
     qdev_prop_set_uint32(dev, "data_width", data_width);
@@ -633,13 +847,26 @@ FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr, hwaddr data_addr,
     sysbus_mmio_map(sbd, 0, ctl_addr);
     sysbus_mmio_map(sbd, 1, data_addr);
 
-    return FW_CFG(dev);
+    s = FW_CFG(dev);
+
+    if (dma_addr && dma_as) {
+        s->dma_as = dma_as;
+        s->dma_enabled = true;
+        s->dma_addr = 0;
+        sysbus_mmio_map(sbd, 2, dma_addr);
+        version |= FW_CFG_VERSION_DMA;
+    }
+
+    fw_cfg_add_i32(s, FW_CFG_ID, version);
+
+    return s;
 }
 
 FWCfgState *fw_cfg_init_mem(hwaddr ctl_addr, hwaddr data_addr)
 {
     return fw_cfg_init_mem_wide(ctl_addr, data_addr,
-                                fw_cfg_data_mem_ops.valid.max_access_size);
+                                fw_cfg_data_mem_ops.valid.max_access_size,
+                                0, NULL);
 }
 
 
@@ -675,7 +902,7 @@ static void fw_cfg_io_realize(DeviceState *dev, Error **errp)
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
 
     memory_region_init_io(&s->comb_iomem, OBJECT(s), &fw_cfg_comb_mem_ops,
-                          FW_CFG(s), "fwcfg", FW_CFG_SIZE);
+                          FW_CFG(s), "fwcfg", FW_CFG_IO_SIZE);
     sysbus_add_io(sbd, s->iobase, &s->comb_iomem);
 }
 
@@ -707,7 +934,7 @@ static void fw_cfg_mem_realize(DeviceState *dev, Error **errp)
     const MemoryRegionOps *data_ops = &fw_cfg_data_mem_ops;
 
     memory_region_init_io(&s->ctl_iomem, OBJECT(s), &fw_cfg_ctl_mem_ops,
-                          FW_CFG(s), "fwcfg.ctl", FW_CFG_SIZE);
+                          FW_CFG(s), "fwcfg.ctl", FW_CFG_CTL_SIZE);
     sysbus_init_mmio(sbd, &s->ctl_iomem);
 
     if (s->data_width > data_ops->valid.max_access_size) {
@@ -725,6 +952,10 @@ static void fw_cfg_mem_realize(DeviceState *dev, Error **errp)
     memory_region_init_io(&s->data_iomem, OBJECT(s), data_ops, FW_CFG(s),
                           "fwcfg.data", data_ops->valid.max_access_size);
     sysbus_init_mmio(sbd, &s->data_iomem);
+
+    memory_region_init_io(&s->dma_iomem, OBJECT(s), &fw_cfg_dma_mem_ops,
+                          FW_CFG(s), "fwcfg.dma", sizeof(dma_addr_t));
+    sysbus_init_mmio(sbd, &s->dma_iomem);
 }
 
 static void fw_cfg_mem_class_init(ObjectClass *klass, void *data)
diff --git a/include/hw/nvram/fw_cfg.h b/include/hw/nvram/fw_cfg.h
index e60d3ca..d0cbc88 100644
--- a/include/hw/nvram/fw_cfg.h
+++ b/include/hw/nvram/fw_cfg.h
@@ -61,6 +61,15 @@ typedef struct FWCfgFiles {
     FWCfgFile f[];
 } FWCfgFiles;
 
+/* Control as first field allows for different structures selected by this
+ * field, which might be useful in the future
+ */
+typedef struct FWCfgDmaAccess {
+    uint32_t control;
+    uint32_t length;
+    uint64_t address;
+} QEMU_PACKED FWCfgDmaAccess;
+
 typedef void (*FWCfgCallback)(void *opaque, uint8_t *data);
 typedef void (*FWCfgReadCallback)(void *opaque, uint32_t offset);
 
@@ -77,10 +86,12 @@ void fw_cfg_add_file_callback(FWCfgState *s, const char *filename,
                               void *data, size_t len);
 void *fw_cfg_modify_file(FWCfgState *s, const char *filename, void *data,
                          size_t len);
+FWCfgState *fw_cfg_init_io_dma(uint32_t iobase, AddressSpace *dma_as);
 FWCfgState *fw_cfg_init_io(uint32_t iobase);
 FWCfgState *fw_cfg_init_mem(hwaddr ctl_addr, hwaddr data_addr);
-FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr, hwaddr data_addr,
-                                 uint32_t data_width);
+FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr,
+                                 hwaddr data_addr, uint32_t data_width,
+                                 hwaddr dma_addr, AddressSpace *dma_as);
 
 FWCfgState *fw_cfg_find(void);
 
-- 
2.4.3