[PATCH RFC 10/19] vfio-user: device region read/write

[Elena Ufimtseva <elena.ufimtseva@oracle.com>]

From: John G Johnson <john.g.johnson@oracle.com>

Send VFIO_REGION_READ and VFIO_REGION_WRITE commands.

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
---
 hw/vfio/user.h   | 16 ++++++++++++++++
 hw/vfio/common.c | 17 +++++++++++++++--
 hw/vfio/pci.c    | 13 +++++++++++++
 hw/vfio/user.c   | 45 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/hw/vfio/user.h b/hw/vfio/user.h
index 9f51e14c7c..17c4d90ef1 100644
--- a/hw/vfio/user.h
+++ b/hw/vfio/user.h
@@ -147,6 +147,18 @@ struct vfio_user_irq_info {
     uint32_t count;
 };
 
+/*
+ * VFIO_USER_REGION_READ
+ * VFIO_USER_REGION_WRITE
+ */
+struct vfio_user_region_rw {
+    vfio_user_hdr_t hdr;
+    uint64_t offset;
+    uint32_t region;
+    uint32_t count;
+    char data[];
+};
+
 void vfio_user_recv(void *opaque);
 void vfio_user_send_reply(VFIOProxy *proxy, char *buf, int ret);
 VFIOProxy *vfio_user_connect_dev(char *sockname, Error **errp);
@@ -154,4 +166,8 @@ void vfio_user_disconnect(VFIOProxy *proxy);
 int vfio_user_validate_version(VFIODevice *vbasedev, Error **errp);
 int vfio_user_get_info(VFIODevice *vbasedev);
 int vfio_user_get_irq_info(VFIODevice *vbasedev, struct vfio_irq_info *info);
+int vfio_user_region_read(VFIODevice *vbasedev, uint32_t index, uint64_t offset,
+                          uint32_t count, void *data);
+int vfio_user_region_write(VFIODevice *vbasedev, uint32_t index,
+                           uint64_t offset, uint32_t count, void *data);
 #endif /* VFIO_USER_H */
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 45acdeeb46..74041cc438 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -40,6 +40,7 @@
 #include "trace.h"
 #include "qapi/error.h"
 #include "migration/migration.h"
+#include "hw/vfio/user.h"
 
 VFIOGroupList vfio_group_list =
     QLIST_HEAD_INITIALIZER(vfio_group_list);
@@ -214,6 +215,7 @@ void vfio_region_write(void *opaque, hwaddr addr,
         uint32_t dword;
         uint64_t qword;
     } buf;
+    int ret;
 
     switch (size) {
     case 1:
@@ -233,7 +235,12 @@ void vfio_region_write(void *opaque, hwaddr addr,
         break;
     }
 
-    if (pwrite(vbasedev->fd, &buf, size, region->fd_offset + addr) != size) {
+    if (vbasedev->proxy != NULL) {
+        ret = vfio_user_region_write(vbasedev, region->nr, addr, size, &data);
+    } else {
+        ret = pwrite(vbasedev->fd, &buf, size, region->fd_offset + addr);
+    }
+    if (ret != size) {
         error_report("%s(%s:region%d+0x%"HWADDR_PRIx", 0x%"PRIx64
                      ",%d) failed: %m",
                      __func__, vbasedev->name, region->nr,
@@ -265,8 +272,14 @@ 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) {
+    if (vbasedev->proxy != NULL) {
+        ret = vfio_user_region_read(vbasedev, region->nr, addr, size, &buf);
+    } else {
+        ret = pread(vbasedev->fd, &buf, size, region->fd_offset + addr);
+    }
+    if (ret != size) {
         error_report("%s(%s:region%d+0x%"HWADDR_PRIx", %d) failed: %m",
                      __func__, vbasedev->name, region->nr,
                      addr, size);
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 029a191bcb..1054978e5e 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3424,6 +3424,19 @@ static void vfio_user_pci_realize(PCIDevice *pdev, Error **errp)
         error_propagate(errp, err);
         goto error;
     }
+    /* Get a copy of config space */
+    ret = vfio_user_region_read(vbasedev, VFIO_PCI_CONFIG_REGION_INDEX, 0,
+                                MIN(pci_config_size(pdev), vdev->config_size),
+                                pdev->config);
+    if (ret < 0) {
+        goto error;
+    }
+
+    /* vfio emulates a lot for us, but some bits need extra love */
+    vdev->emulated_config_bits = g_malloc0(vdev->config_size);
+
+    /* QEMU can also add or extend BARs */
+    memset(vdev->emulated_config_bits + PCI_BASE_ADDRESS_0, 0xff, 6 * 4);
 
     return;
 
diff --git a/hw/vfio/user.c b/hw/vfio/user.c
index a282b7b7b8..2bb6f8650e 100644
--- a/hw/vfio/user.c
+++ b/hw/vfio/user.c
@@ -634,3 +634,48 @@ int vfio_user_get_irq_info(VFIODevice *vbasedev, struct vfio_irq_info *info)
     memcpy(info, &msg.argsz, sizeof(*info));
     return 0;
 }
+
+int vfio_user_region_read(VFIODevice *vbasedev, uint32_t index, uint64_t offset,
+                                 uint32_t count, void *data)
+{
+    g_autofree struct vfio_user_region_rw *msgp = NULL;
+    int size = sizeof(*msgp) + count;
+
+    /* most reads are just registers, only allocate for larger ones */
+    msgp = g_malloc0(size);
+    vfio_user_request_msg(&msgp->hdr, VFIO_USER_REGION_READ, sizeof(*msgp), 0);
+    msgp->offset = offset;
+    msgp->region = index;
+    msgp->count = count;
+
+    vfio_user_send_recv(vbasedev->proxy, &msgp->hdr, NULL, size);
+    if (msgp->hdr.flags & VFIO_USER_ERROR) {
+        return -msgp->hdr.error_reply;
+    } else if (msgp->count > count) {
+        return -E2BIG;
+    } else {
+        memcpy(data, &msgp->data, msgp->count);
+    }
+
+    return msgp->count;
+}
+
+int vfio_user_region_write(VFIODevice *vbasedev, uint32_t index,
+                           uint64_t offset, uint32_t count, void *data)
+{
+    g_autofree struct vfio_user_region_rw *msgp = NULL;
+    int size = sizeof(*msgp) + count;
+
+    /* most writes are just registers, only allocate for larger ones */
+    msgp = g_malloc0(size);
+    vfio_user_request_msg(&msgp->hdr, VFIO_USER_REGION_WRITE, size,
+                          VFIO_USER_NO_REPLY);
+    msgp->offset = offset;
+    msgp->region = index;
+    msgp->count = count;
+    memcpy(&msgp->data, data, count);
+
+    vfio_user_send(vbasedev->proxy, &msgp->hdr, NULL);
+
+    return count;
+}
-- 
2.25.1