[Qemu-devel] [PATCH] Support virtio-scsi-pci adapter hot-plug

[Kelvin Wang]

Support the virtio-scsi-pci adapter hot-plug. However, this patch can only make
adapter hot-plugable. More effort is needed for LUN hot-plug. Actually, that is 
the most valuable feature to virtio-scsi.

Following the steps as follows can give an intuitive understanding of this 
feature after applying the patch to QEMU v1.1.0-rc3.

1, Generate a image file:
qemu-img create -f qcow2 test.img 2G

2, Run qemu with the option -monitor.

3, In the guest, insert necessary modules:
for m in acpiphp pci_hotplug; do sudo modprobe ${m}; done

4, In the qemu monitor,hot add a virtio-scsi-pci adapter:
(qemu)pci_add auto storage if=virtio-scsi-pci

5, Check whether the controller was added:
Guest: lspci
Qemu: (qemu)info qtree

Signed-off-by: Kelvin Wang <address@hidden>
Signed-off-by: Sheng Liu <address@hidden>
---
 blockdev.c       |   19 +++++++++++++++----
 blockdev.h       |    3 ++-
 hw/pci-hotplug.c |   15 +++++++++++++++
 3 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 67895b2..ecb82bf 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -31,6 +31,7 @@ static const char *const if_name[IF_COUNT] = {
     [IF_MTD] = "mtd",
     [IF_SD] = "sd",
     [IF_VIRTIO] = "virtio",
+       [IF_VIRTIO_SCSI] = "virtio-scsi",
     [IF_XEN] = "xen",
 };

@@ -436,7 +437,8 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)

     on_write_error = BLOCK_ERR_STOP_ENOSPC;
     if ((buf = qemu_opt_get(opts, "werror")) != NULL) {
-        if (type != IF_IDE && type != IF_SCSI && type != IF_VIRTIO && type != 
IF_NONE) {
+        if (type != IF_IDE && type != IF_SCSI && type != IF_VIRTIO && 
+                               type != IF_VIRTIO_SCSI && type != IF_NONE) {
             error_report("werror is not supported by this bus type");
             return NULL;
         }
@@ -449,7 +451,8 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)

     on_read_error = BLOCK_ERR_REPORT;
     if ((buf = qemu_opt_get(opts, "rerror")) != NULL) {
-        if (type != IF_IDE && type != IF_VIRTIO && type != IF_SCSI && type != 
IF_NONE) {
+        if (type != IF_IDE && type != IF_VIRTIO && type != IF_SCSI && 
+                               IF_VIRTIO_SCSI && type != IF_NONE) {
             error_report("rerror is not supported by this bus type");
             return NULL;
         }
@@ -461,7 +464,7 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
     }

     if ((devaddr = qemu_opt_get(opts, "addr")) != NULL) {
-        if (type != IF_VIRTIO) {
+        if (type != IF_VIRTIO || type != IF_VIRTIO_SCSI) {
             error_report("addr is not supported by this bus type");
             return NULL;
         }
@@ -579,6 +582,14 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
         if (devaddr)
             qemu_opt_set(opts, "addr", devaddr);
         break;
+       case IF_VIRTIO_SCSI:
+               opts = qemu_opts_create(qemu_find_opts("device"), NULL, 0);
+               qemu_opt_set(opts, "driver", "virtio-scsi-pci");
+               qemu_opt_set(opts, "drive", dinfo->id);
+               if (devaddr) {
+                   qemu_opt_set(opts, "addr", devaddr);
+               }
+               break;
     default:
         abort();
     }
@@ -604,7 +615,7 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
         ro = 1;
     } else if (ro == 1) {
         if (type != IF_SCSI && type != IF_VIRTIO && type != IF_FLOPPY &&
-            type != IF_NONE && type != IF_PFLASH) {
+            type != IF_NONE && type != IF_PFLASH && IF_VIRTIO_SCSI) {
             error_report("readonly not supported by this bus type");
             goto err;
         }
diff --git a/blockdev.h b/blockdev.h
index 260e16b..96f40a5 100644
--- a/blockdev.h
+++ b/blockdev.h
@@ -22,7 +22,8 @@ void blockdev_auto_del(BlockDriverState *bs);
 typedef enum {
     IF_DEFAULT = -1,            /* for use with drive_add() only */
     IF_NONE,
-    IF_IDE, IF_SCSI, IF_FLOPPY, IF_PFLASH, IF_MTD, IF_SD, IF_VIRTIO, IF_XEN,
+    IF_IDE, IF_SCSI, IF_FLOPPY, IF_PFLASH, IF_MTD, IF_SD, IF_VIRTIO, IF_XEN, 
+       IF_VIRTIO_SCSI,
     IF_COUNT
 } BlockInterfaceType;

diff --git a/hw/pci-hotplug.c b/hw/pci-hotplug.c
index c55d8b9..4f5c022 100644
--- a/hw/pci-hotplug.c
+++ b/hw/pci-hotplug.c
@@ -154,6 +154,8 @@ static PCIDevice *qemu_pci_hot_add_storage(Monitor *mon,
             type = IF_SCSI;
         else if (!strcmp(buf, "virtio")) {
             type = IF_VIRTIO;
+               } else if (!strcmp(buf, "virtio-scsi")) {
+            type = IF_VIRTIO_SCSI;
         } else {
             monitor_printf(mon, "type %s not a hotpluggable PCI device.\n", 
buf);
             return NULL;
@@ -211,6 +213,19 @@ static PCIDevice *qemu_pci_hot_add_storage(Monitor *mon,
         if (qdev_init(&dev->qdev) < 0)
             dev = NULL;
         break;
+       case IF_VIRTIO_SCSI:
+               dev = pci_create(bus, devfn, "virtio-scsi-pci");
+               if (qdev_init(&dev->qdev) < 0) {
+                       dev = NULL;
+               }
+
+               if (dev && dinfo) {
+                       if (scsi_hot_add(mon, &dev->qdev, dinfo, 0) != 0) {
+                               qdev_unplug(&dev->qdev, NULL);
+                               dev = NULL;
+                       }
+               }
+               break;
     default:
         dev = NULL;
     }
-- 
1.7.1