These patches implement the hotplug support for virtio-scsi. When a new device attaches/detaches to virtio-scsi bus via device_add/device_del commands, the HBA driver in guest kernel will be signaled to add/remove the scsi device. Cong Meng (2): scsi bus: introduce hotplug() and hot_unplug() interfaces for SCSI bus virtio-scsi: Implement hotplug support for virtio-scsi hw/scsi-bus.c | 16 +++++++++++- hw/scsi.h | 2 + hw/virtio-scsi.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 86 insertions(+), 4 deletions(-) -- 1.7.7
Cong Meng
2012-Jun-20 06:47 UTC
[PATCH 1/2] scsi bus: introduce hotplug() and hot_unplug() interfaces for SCSI bus
Add two interfaces hotplug() and hot_unplug() to scsi bus info.
The embody scsi bus can implement these two interfaces to signal the HBA driver
of guest kernel to add/remove the scsi device in question.
Signed-off-by: Cong Meng <mc at linux.vnet.ibm.com>
Signed-off-by: Sen Wang <senwang at linux.vnet.ibm.com>
---
hw/scsi-bus.c | 16 +++++++++++++++-
hw/scsi.h | 2 ++
2 files changed, 17 insertions(+), 1 deletions(-)
diff --git a/hw/scsi-bus.c b/hw/scsi-bus.c
index dbdb99c..cc3ec75 100644
--- a/hw/scsi-bus.c
+++ b/hw/scsi-bus.c
@@ -177,6 +177,10 @@ static int scsi_qdev_init(DeviceState *qdev)
dev);
}
+ if (bus->info->hotplug) {
+ bus->info->hotplug(bus, dev);
+ }
+
err:
return rc;
}
@@ -1539,6 +1543,16 @@ static int get_scsi_requests(QEMUFile *f, void *pv,
size_t size)
return 0;
}
+static int scsi_qdev_unplug(DeviceState *qdev)
+{
+ SCSIDevice *dev = SCSI_DEVICE(qdev);
+ SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, dev->qdev.parent_bus);
+
+ if (bus->info->hot_unplug)
+ bus->info->hot_unplug(bus, dev);
+ return qdev_simple_unplug_cb(qdev);
+}
+
const VMStateInfo vmstate_info_scsi_requests = {
.name = "scsi-requests",
.get = get_scsi_requests,
@@ -1575,7 +1589,7 @@ static void scsi_device_class_init(ObjectClass *klass,
void *data)
DeviceClass *k = DEVICE_CLASS(klass);
k->bus_info = &scsi_bus_info;
k->init = scsi_qdev_init;
- k->unplug = qdev_simple_unplug_cb;
+ k->unplug = scsi_qdev_unplug;
k->exit = scsi_qdev_exit;
}
diff --git a/hw/scsi.h b/hw/scsi.h
index 2eb66f7..5768071 100644
--- a/hw/scsi.h
+++ b/hw/scsi.h
@@ -130,6 +130,8 @@ struct SCSIBusInfo {
void (*transfer_data)(SCSIRequest *req, uint32_t arg);
void (*complete)(SCSIRequest *req, uint32_t arg, size_t resid);
void (*cancel)(SCSIRequest *req);
+ void (*hotplug)(SCSIBus *bus, SCSIDevice *dev);
+ void (*hot_unplug)(SCSIBus *bus, SCSIDevice *dev);
QEMUSGList *(*get_sg_list)(SCSIRequest *req);
void (*save_request)(QEMUFile *f, SCSIRequest *req);
--
1.7.7
Cong Meng
2012-Jun-20 06:47 UTC
[PATCH 2/2] virtio-scsi: Implement hotplug support for virtio-scsi
Implement the hotplug() and hot_unplug() interfaces in virtio-scsi, by signal
the virtio_scsi.ko in guest kernel via event virtual queue.
The counterpart patch of virtio_scsi.ko will be sent soon in another thread.
Signed-off-by: Cong Meng <mc at linux.vnet.ibm.com>
Signed-off-by: Sen Wang <senwang at linux.vnet.ibm.com>
---
hw/virtio-scsi.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 69 insertions(+), 3 deletions(-)
diff --git a/hw/virtio-scsi.c b/hw/virtio-scsi.c
index e8328f4..626ec5f 100644
--- a/hw/virtio-scsi.c
+++ b/hw/virtio-scsi.c
@@ -24,6 +24,10 @@
#define VIRTIO_SCSI_MAX_TARGET 255
#define VIRTIO_SCSI_MAX_LUN 16383
+/* Feature Bits */
+#define VIRTIO_SCSI_F_INOUT 0
+#define VIRTIO_SCSI_F_HOTPLUG 1
+
/* Response codes */
#define VIRTIO_SCSI_S_OK 0
#define VIRTIO_SCSI_S_OVERRUN 1
@@ -60,6 +64,11 @@
#define VIRTIO_SCSI_T_TRANSPORT_RESET 1
#define VIRTIO_SCSI_T_ASYNC_NOTIFY 2
+/* Reasons of transport reset event */
+#define VIRTIO_SCSI_EVT_RESET_HARD 0
+#define VIRTIO_SCSI_EVT_RESET_RESCAN 1
+#define VIRTIO_SCSI_EVT_RESET_REMOVED 2
+
/* SCSI command request, followed by data-out */
typedef struct {
uint8_t lun[8]; /* Logical Unit Number */
@@ -206,11 +215,12 @@ static void qemu_sgl_init_external(QEMUSGList *qsgl,
struct iovec *sg,
static void virtio_scsi_parse_req(VirtIOSCSI *s, VirtQueue *vq,
VirtIOSCSIReq *req)
{
- assert(req->elem.out_num && req->elem.in_num);
+ assert(req->elem.in_num);
req->vq = vq;
req->dev = s;
req->sreq = NULL;
- req->req.buf = req->elem.out_sg[0].iov_base;
+ if (req->elem.out_num)
+ req->req.buf = req->elem.out_sg[0].iov_base;
req->resp.buf = req->elem.in_sg[0].iov_base;
if (req->elem.out_num > 1) {
@@ -405,6 +415,10 @@ static void virtio_scsi_handle_ctrl(VirtIODevice *vdev,
VirtQueue *vq)
}
}
+static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
+{
+}
+
static void virtio_scsi_command_complete(SCSIRequest *r, uint32_t status,
size_t resid)
{
@@ -541,6 +555,7 @@ static void virtio_scsi_set_config(VirtIODevice *vdev,
static uint32_t virtio_scsi_get_features(VirtIODevice *vdev,
uint32_t requested_features)
{
+ requested_features |= (1UL << VIRTIO_SCSI_F_HOTPLUG);
return requested_features;
}
@@ -568,6 +583,55 @@ static int virtio_scsi_load(QEMUFile *f, void *opaque, int
version_id)
return 0;
}
+static void virtio_scsi_push_event(VirtIOSCSI *s, uint32_t target, uint32_t
lun,
+ uint32_t event, uint32_t reason)
+{
+ VirtIOSCSIReq *req;
+ VirtIOSCSIEvent *evt;
+
+ if ((req = virtio_scsi_pop_req(s, s->event_vq))) {
+ int in_size;
+ if (req->elem.out_num || req->elem.in_num != 1) {
+ virtio_scsi_bad_req();
+ }
+
+ in_size = req->elem.in_sg[0].iov_len;
+ if (in_size < sizeof(VirtIOSCSIEvent)) {
+ virtio_scsi_bad_req();
+ }
+
+ evt = req->resp.event;
+ evt->event = event;
+ evt->reason = reason;
+ evt->lun[0] = 0;
+ evt->lun[1] = target;
+ evt->lun[2] = (lun >> 8);
+ evt->lun[3] = lun & 0xFF;
+ virtio_scsi_complete_req(req);
+ }
+}
+
+static void virtio_scsi_hotplug(SCSIBus *bus, SCSIDevice *dev)
+{
+ VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
+
+ if (((s->vdev.guest_features >> VIRTIO_SCSI_F_HOTPLUG) & 1)
&&
+ (s->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK)) {
+ virtio_scsi_push_event(s, dev->id, dev->lun,
+ VIRTIO_SCSI_T_TRANSPORT_RESET, VIRTIO_SCSI_EVT_RESET_RESCAN);
+ }
+}
+
+static void virtio_scsi_hot_unplug(SCSIBus *bus, SCSIDevice *dev)
+{
+ VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
+
+ if ((s->vdev.guest_features >> VIRTIO_SCSI_F_HOTPLUG) & 1) {
+ virtio_scsi_push_event(s, dev->id, dev->lun,
+ VIRTIO_SCSI_T_TRANSPORT_RESET, VIRTIO_SCSI_EVT_RESET_REMOVED);
+ }
+}
+
static struct SCSIBusInfo virtio_scsi_scsi_info = {
.tcq = true,
.max_channel = VIRTIO_SCSI_MAX_CHANNEL,
@@ -576,6 +640,8 @@ static struct SCSIBusInfo virtio_scsi_scsi_info = {
.complete = virtio_scsi_command_complete,
.cancel = virtio_scsi_request_cancelled,
+ .hotplug = virtio_scsi_hotplug,
+ .hot_unplug = virtio_scsi_hot_unplug,
.get_sg_list = virtio_scsi_get_sg_list,
.save_request = virtio_scsi_save_request,
.load_request = virtio_scsi_load_request,
@@ -604,7 +670,7 @@ VirtIODevice *virtio_scsi_init(DeviceState *dev,
VirtIOSCSIConf *proxyconf)
s->ctrl_vq = virtio_add_queue(&s->vdev, VIRTIO_SCSI_VQ_SIZE,
virtio_scsi_handle_ctrl);
s->event_vq = virtio_add_queue(&s->vdev, VIRTIO_SCSI_VQ_SIZE,
- NULL);
+ virtio_scsi_handle_event);
for (i = 0; i < s->conf->num_queues; i++) {
s->cmd_vqs[i] = virtio_add_queue(&s->vdev,
VIRTIO_SCSI_VQ_SIZE,
virtio_scsi_handle_cmd);
--
1.7.7
Stefan Hajnoczi
2012-Jun-21 10:56 UTC
[Qemu-devel] [PATCH 2/2] virtio-scsi: Implement hotplug support for virtio-scsi
On Wed, Jun 20, 2012 at 7:47 AM, Cong Meng <mc at linux.vnet.ibm.com> wrote:> Implement the hotplug() and hot_unplug() interfaces in virtio-scsi, by signal > the virtio_scsi.ko in guest kernel via event virtual queue. > > The counterpart patch of virtio_scsi.ko will be sent soon in another thread. > > Signed-off-by: Cong Meng <mc at linux.vnet.ibm.com> > Signed-off-by: Sen Wang <senwang at linux.vnet.ibm.com> > --- > ?hw/virtio-scsi.c | ? 72 +++++++++++++++++++++++++++++++++++++++++++++++++++-- > ?1 files changed, 69 insertions(+), 3 deletions(-)I compared against the virtio-scsi specification and this looks good: http://ozlabs.org/~rusty/virtio-spec/virtio-0.9.5.pdf Dropped events and event throttling are not implemented by this patch. This means that the guest can miss events if it runs out of event queue elements. A scenario that might be able to trigger this is if multiple LUNs are hotplugged in a single QEMU monitor callback. Implementing dropped events is easy in hw/virtio-scsi.c. Keep a bool or counter of dropped events and report them when the guest kicks us with a free event element (virtio_scsi_handle_event). Stefan