On 5/7/25 17:20, John Levon wrote:
Now we have the region info cache, add ->region_read/write device I/O
operations instead of explicit pread()/pwrite() system calls.

No S-o-b. Please reply with one.


Thanks,

C.


---
  include/hw/vfio/vfio-device.h | 18 ++++++++++++++++++
  hw/vfio/device.c              | 34 ++++++++++++++++++++++++++++++++++
  hw/vfio/pci.c                 | 28 ++++++++++++++--------------
  hw/vfio/region.c              | 17 +++++++++++------
  4 files changed, 77 insertions(+), 20 deletions(-)

diff --git a/include/hw/vfio/vfio-device.h b/include/hw/vfio/vfio-device.h
index 4fff3dcee3..8bcb3c19f6 100644
--- a/include/hw/vfio/vfio-device.h
+++ b/include/hw/vfio/vfio-device.h
@@ -188,6 +188,24 @@ struct VFIODeviceIOOps {
       * Configure IRQs as defined by @irqs.
       */
      int (*set_irqs)(VFIODevice *vdev, struct vfio_irq_set *irqs);
+
+    /**
+     * @region_read
+     *
+     * Read @size bytes from the region @nr at offset @off into the buffer
+     * @data.
+     */
+    int (*region_read)(VFIODevice *vdev, uint8_t nr, off_t off, uint32_t size,
+                       void *data);
+
+    /**
+     * @region_write
+     *
+     * Write @size bytes to the region @nr at offset @off from the buffer
+     * @data.
+     */
+    int (*region_write)(VFIODevice *vdev, uint8_t nr, off_t off, uint32_t size,
+                        void *data);
  };
void vfio_device_prepare(VFIODevice *vbasedev, VFIOContainerBase *bcontainer,
diff --git a/hw/vfio/device.c b/hw/vfio/device.c
index 77b0675abe..0b2cd90d64 100644
--- a/hw/vfio/device.c
+++ b/hw/vfio/device.c
@@ -505,9 +505,43 @@ static int vfio_device_io_set_irqs(VFIODevice *vbasedev,
      return ret < 0 ? -errno : ret;
  }
+static int vfio_device_io_region_read(VFIODevice *vbasedev, uint8_t index,
+                                      off_t off, uint32_t size, void *data)
+{
+    struct vfio_region_info *info;
+    int ret;
+
+    ret = vfio_device_get_region_info(vbasedev, index, &info);
+    if (ret != 0) {
+        return ret;
+    }
+
+    ret = pread(vbasedev->fd, data, size, info->offset + off);
+
+    return ret < 0 ? -errno : ret;
+}
+
+static int vfio_device_io_region_write(VFIODevice *vbasedev, uint8_t index,
+                                       off_t off, uint32_t size, void *data)
+{
+    struct vfio_region_info *info;
+    int ret;
+
+    ret = vfio_device_get_region_info(vbasedev, index, &info);
+    if (ret != 0) {
+        return ret;
+    }
+
+    ret = pwrite(vbasedev->fd, data, size, info->offset + off);
+
+    return ret < 0 ? -errno : ret;
+}
+
  static VFIODeviceIOOps vfio_device_io_ops_ioctl = {
      .device_feature = vfio_device_io_device_feature,
      .get_region_info = vfio_device_io_get_region_info,
      .get_irq_info = vfio_device_io_get_irq_info,
      .set_irqs = vfio_device_io_set_irqs,
+    .region_read = vfio_device_io_region_read,
+    .region_write = vfio_device_io_region_write,
  };
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 9136cf52c8..1236de315d 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -918,18 +918,22 @@ static void vfio_pci_load_rom(VFIOPCIDevice *vdev)
      memset(vdev->rom, 0xff, size);
while (size) {
-        bytes = pread(vbasedev->fd, vdev->rom + off,
-                      size, vdev->rom_offset + off);
+        bytes = vbasedev->io_ops->region_read(vbasedev,
+                                              VFIO_PCI_ROM_REGION_INDEX,
+                                              off, size, vdev->rom + off);
+
          if (bytes == 0) {
              break;
          } else if (bytes > 0) {
              off += bytes;
              size -= bytes;
          } else {
-            if (errno == EINTR || errno == EAGAIN) {
+            if (bytes == -EINTR || bytes == -EAGAIN) {
                  continue;
              }
-            error_report("vfio: Error reading device ROM: %m");
+            error_report("vfio: Error reading device ROM: %s",
+                         strreaderror(bytes));
+
              break;
          }
      }
@@ -969,22 +973,18 @@ static void vfio_pci_load_rom(VFIOPCIDevice *vdev)
  static int vfio_pci_config_space_read(VFIOPCIDevice *vdev, off_t offset,
                                        uint32_t size, void *data)
  {
-    ssize_t ret;
-
-    ret = pread(vdev->vbasedev.fd, data, size, vdev->config_offset + offset);
-
-    return ret < 0 ? -errno : (int)ret;
+    return vdev->vbasedev.io_ops->region_read(&vdev->vbasedev,
+                                              VFIO_PCI_CONFIG_REGION_INDEX,
+                                              offset, size, data);
  }
/* "Raw" write of underlying config space. */
  static int vfio_pci_config_space_write(VFIOPCIDevice *vdev, off_t offset,
                                         uint32_t size, void *data)
  {
-    ssize_t ret;
-
-    ret = pwrite(vdev->vbasedev.fd, data, size, vdev->config_offset + offset);
-
-    return ret < 0 ? -errno : (int)ret;
+    return vdev->vbasedev.io_ops->region_write(&vdev->vbasedev,
+                                               VFIO_PCI_CONFIG_REGION_INDEX,
+                                               offset, size, data);
  }
static uint64_t vfio_rom_read(void *opaque, hwaddr addr, unsigned size)
diff --git a/hw/vfio/region.c b/hw/vfio/region.c
index ef2630cac3..34752c3f65 100644
--- a/hw/vfio/region.c
+++ b/hw/vfio/region.c
@@ -45,6 +45,7 @@ void vfio_region_write(void *opaque, hwaddr addr,
          uint32_t dword;
          uint64_t qword;
      } buf;
+    int ret;
switch (size) {
      case 1:
@@ -64,11 +65,13 @@ void vfio_region_write(void *opaque, hwaddr addr,
          break;
      }
- if (pwrite(vbasedev->fd, &buf, size, region->fd_offset + addr) != size) {
+    ret = vbasedev->io_ops->region_write(vbasedev, region->nr,
+                                         addr, size, &buf);
+    if (ret != size) {
          error_report("%s(%s:region%d+0x%"HWADDR_PRIx", 0x%"PRIx64
-                     ",%d) failed: %m",
+                     ",%d) failed: %s",
                       __func__, vbasedev->name, region->nr,
-                     addr, data, size);
+                     addr, data, size, strwriteerror(ret));
      }
trace_vfio_region_write(vbasedev->name, region->nr, addr, data, size);
@@ -96,11 +99,13 @@ uint64_t vfio_region_read(void *opaque,
          uint64_t qword;
      } buf;
      uint64_t data = 0;
+    int ret;
- if (pread(vbasedev->fd, &buf, size, region->fd_offset + addr) != size) {
-        error_report("%s(%s:region%d+0x%"HWADDR_PRIx", %d) failed: %m",
+    ret = vbasedev->io_ops->region_read(vbasedev, region->nr, addr, size, 
&buf);
+    if (ret != size) {
+        error_report("%s(%s:region%d+0x%"HWADDR_PRIx", %d) failed: %s",
                       __func__, vbasedev->name, region->nr,
-                     addr, size);
+                     addr, size, strreaderror(ret));
          return (uint64_t)-1;
      }
      switch (size) {


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