Re: [Qemu-devel] [PATCH 0/2] virtio: reset all qbuses too when writing to the status field

[Michael S. Tsirkin]

On Sun, Dec 16, 2012 at 08:31:16PM +0100, Paolo Bonzini wrote:
> Il 16/12/2012 18:04, Michael S. Tsirkin ha scritto:
> > On Thu, Dec 13, 2012 at 09:54:23AM +0100, Paolo Bonzini wrote:
> >> Il 12/12/2012 22:27, Michael S. Tsirkin ha scritto:
> >>>>> Maybe it's obvious to you that qdev_reset_all(x)
> >>>>> does a soft reset and what soft reset means
> >>>>> for each bus type
> >>>>
> >>>> We can define soft reset to be *independent* of the bus type.  As you
> >>>> said, you access it with a device register.
> >>>
> >>> I think qemu has one type of reset ATM which is the hard reset.
> >>
> >> A hard reset would kill BARs and configuration space too.
> >> qdev_reset_all doesn't.  Ergo, it is not a hard reset.
> >>
> >> But hey, I'm not wed to names.  Let's call it device-level reset and
> >> bus-level reset.  Whatever.
> > 
> > It's not a question of a name.
> > 
> > ATM qemu supports one kind of reset because it's a kind of reset all
> > hardware supports.  The moment we start inventing
> > our own one we need to document exactly what it means.
> 
> We have two, DeviceClass's and BusClass's reset members.
> 
> I'll make a patch to document them.

And qdev_reset_all needs documentation too.
Another issue is that this really should be
part of generic code, not transport-specific one.

The reason we can't do this is because virtio
does not have access to DeviceState: all it has
is a void * binding opaque.
However this is not really a feature - it seems we
should be able to pass DeviceState instead.

How about the following? Then we can put reset
in generic code where it belongs.
It's untested - really kind of pseudo code - and
s390 is still to be updated.

Posting to see what does everyone thinks.

---

diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 3ea4140..63ae888 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -98,34 +98,34 @@ bool virtio_is_big_endian(void);
 
 /* virtio device */
 
-static void virtio_pci_notify(void *opaque, uint16_t vector)
+static void virtio_pci_notify(DeviceState *d, uint16_t vector)
 {
-    VirtIOPCIProxy *proxy = opaque;
+    VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev);
     if (msix_enabled(&proxy->pci_dev))
         msix_notify(&proxy->pci_dev, vector);
     else
         qemu_set_irq(proxy->pci_dev.irq[0], proxy->vdev->isr & 1);
 }
 
-static void virtio_pci_save_config(void * opaque, QEMUFile *f)
+static void virtio_pci_save_config(DeviceState *d, QEMUFile *f)
 {
-    VirtIOPCIProxy *proxy = opaque;
+    VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev);
     pci_device_save(&proxy->pci_dev, f);
     msix_save(&proxy->pci_dev, f);
     if (msix_present(&proxy->pci_dev))
         qemu_put_be16(f, proxy->vdev->config_vector);
 }
 
-static void virtio_pci_save_queue(void * opaque, int n, QEMUFile *f)
+static void virtio_pci_save_queue(DeviceState *d, int n, QEMUFile *f)
 {
-    VirtIOPCIProxy *proxy = opaque;
+    VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev);
     if (msix_present(&proxy->pci_dev))
         qemu_put_be16(f, virtio_queue_vector(proxy->vdev, n));
 }
 
-static int virtio_pci_load_config(void * opaque, QEMUFile *f)
+static int virtio_pci_load_config(DeviceState *d, QEMUFile *f)
 {
-    VirtIOPCIProxy *proxy = opaque;
+    VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev);
     int ret;
     ret = pci_device_load(&proxy->pci_dev, f);
     if (ret) {
@@ -144,9 +144,9 @@ static int virtio_pci_load_config(void * opaque, QEMUFile 
*f)
     return 0;
 }
 
-static int virtio_pci_load_queue(void * opaque, int n, QEMUFile *f)
+static int virtio_pci_load_queue(DeviceState *d, int n, QEMUFile *f)
 {
-    VirtIOPCIProxy *proxy = opaque;
+    VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev);
     uint16_t vector;
     if (msix_present(&proxy->pci_dev)) {
         qemu_get_be16s(f, &vector);
@@ -464,9 +464,9 @@ static void virtio_write_config(PCIDevice *pci_dev, 
uint32_t address,
     }
 }
 
-static unsigned virtio_pci_get_features(void *opaque)
+static unsigned virtio_pci_get_features(DeviceState *d)
 {
-    VirtIOPCIProxy *proxy = opaque;
+    VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev);
     return proxy->host_features;
 }
 
@@ -568,9 +568,9 @@ static void kvm_virtio_pci_vector_release(PCIDevice *dev, 
unsigned vector)
     }
 }
 
-static int virtio_pci_set_guest_notifier(void *opaque, int n, bool assign)
+static int virtio_pci_set_guest_notifier(DeviceState *d, int n, bool assign)
 {
-    VirtIOPCIProxy *proxy = opaque;
+    VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev);
     VirtQueue *vq = virtio_get_queue(proxy->vdev, n);
     EventNotifier *notifier = virtio_queue_get_guest_notifier(vq);
 
@@ -588,15 +588,15 @@ static int virtio_pci_set_guest_notifier(void *opaque, 
int n, bool assign)
     return 0;
 }
 
-static bool virtio_pci_query_guest_notifiers(void *opaque)
+static bool virtio_pci_query_guest_notifiers(DeviceState *d)
 {
-    VirtIOPCIProxy *proxy = opaque;
+    VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev);
     return msix_enabled(&proxy->pci_dev);
 }
 
-static int virtio_pci_set_guest_notifiers(void *opaque, bool assign)
+static int virtio_pci_set_guest_notifiers(DeviceState *d, bool assign)
 {
-    VirtIOPCIProxy *proxy = opaque;
+    VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev);
     VirtIODevice *vdev = proxy->vdev;
     int r, n;
 
@@ -612,7 +612,7 @@ static int virtio_pci_set_guest_notifiers(void *opaque, 
bool assign)
             break;
         }
 
-        r = virtio_pci_set_guest_notifier(opaque, n, assign);
+        r = virtio_pci_set_guest_notifier(d, n, assign);
         if (r < 0) {
             goto assign_error;
         }
@@ -638,14 +638,14 @@ assign_error:
     /* We get here on assignment failure. Recover by undoing for VQs 0 .. n. */
     assert(assign);
     while (--n >= 0) {
-        virtio_pci_set_guest_notifier(opaque, n, !assign);
+        virtio_pci_set_guest_notifier(d, n, !assign);
     }
     return r;
 }
 
-static int virtio_pci_set_host_notifier(void *opaque, int n, bool assign)
+static int virtio_pci_set_host_notifier(DeviceState *d, int n, bool assign)
 {
-    VirtIOPCIProxy *proxy = opaque;
+    VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev);
 
     /* Stop using ioeventfd for virtqueue kick if the device starts using host
      * notifiers.  This makes it easy to avoid stepping on each others' toes.
@@ -661,9 +661,9 @@ static int virtio_pci_set_host_notifier(void *opaque, int 
n, bool assign)
     return virtio_pci_set_host_notifier_internal(proxy, n, assign, false);
 }
 
-static void virtio_pci_vmstate_change(void *opaque, bool running)
+static void virtio_pci_vmstate_change(DeviceState *d, bool running)
 {
-    VirtIOPCIProxy *proxy = opaque;
+    VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev);
 
     if (running) {
         /* Try to find out if the guest has bus master disabled, but is
diff --git a/hw/virtio.h b/hw/virtio.h
index 7c17f7b..b9eeaa5 100644
--- a/hw/virtio.h
+++ b/hw/virtio.h
@@ -91,17 +91,17 @@ typedef struct VirtQueueElement
 } VirtQueueElement;
 
 typedef struct {
-    void (*notify)(void * opaque, uint16_t vector);
-    void (*save_config)(void * opaque, QEMUFile *f);
-    void (*save_queue)(void * opaque, int n, QEMUFile *f);
-    int (*load_config)(void * opaque, QEMUFile *f);
-    int (*load_queue)(void * opaque, int n, QEMUFile *f);
-    int (*load_done)(void * opaque, QEMUFile *f);
-    unsigned (*get_features)(void * opaque);
-    bool (*query_guest_notifiers)(void * opaque);
-    int (*set_guest_notifiers)(void * opaque, bool assigned);
-    int (*set_host_notifier)(void * opaque, int n, bool assigned);
-    void (*vmstate_change)(void * opaque, bool running);
+    void (*notify)(DeviceState *d, uint16_t vector);
+    void (*save_config)(DeviceState *d, QEMUFile *f);
+    void (*save_queue)(DeviceState *d, int n, QEMUFile *f);
+    int (*load_config)(DeviceState *d, QEMUFile *f);
+    int (*load_queue)(DeviceState *d, int n, QEMUFile *f);
+    int (*load_done)(DeviceState *d, QEMUFile *f);
+    unsigned (*get_features)(DeviceState *d);
+    bool (*query_guest_notifiers)(DeviceState *d);
+    int (*set_guest_notifiers)(DeviceState *d, bool assigned);
+    int (*set_host_notifier)(DeviceState *d, int n, bool assigned);
+    void (*vmstate_change)(DeviceState *d, bool running);
 } VirtIOBindings;
 
 #define VIRTIO_PCI_QUEUE_MAX 64
@@ -128,7 +128,7 @@ struct VirtIODevice
     void (*set_status)(VirtIODevice *vdev, uint8_t val);
     VirtQueue *vq;
     const VirtIOBindings *binding;
-    void *binding_opaque;
+    DeviceState *binding_opaque;
     uint16_t device_id;
     bool vm_running;
     VMChangeStateEntry *vmstate;

-- 
MST