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

[Kelvin Wang]

On Wed, May 23, 2012 at 05:12:16PM +0300, Michael S. Tsirkin wrote:
> On Wed, May 23, 2012 at 09:52:06PM +0800, Kelvin Wang wrote:
> > 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>
> 
> NAK
> 
> Do not use pci_add. It is a compatibility command.
> Use the new style device_add.
> Same for if=.
> 
> I think you won't need any changes then?
OK, Thanks!
> 
> > ---
> >  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",
> 
> weird indentation
> 
> >      [IF_XEN] = "xen",
> >  };
> > 
> 
> I think blockdev is a legacy thing. You are
> supposed to use the new style device-add. No?
> 
> > @@ -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) {
> 
> code dupicated here and below. add a function?
> 
> >              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) {
> 
> typo? IF_VIRTIO_SCSI is always != 0 ...
Ouch, ashamed for my carelessness.
> 
> >              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,
> 
> weird  indentation
> 
> >      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;
> >      }
> 
> Here I am sure.
> Do not keep adding stuff to pci-hotplug.
> New devices should use device-add.
> 
> > -- 
> > 1.7.1
>