[Virtio-for-kvm] [PATCH 6/7] userspace virtio

[Dor Laor <dor.laor@xxxxxxxxx>]

From 1b493ba192cd677d9feb886eb494cb266a8604e2 Mon Sep 17 00:00:00 2001
From: Dor Laor <dor.laor@xxxxxxxxxxxx>
Date: Thu, 20 Dec 2007 10:48:32 +0200
Subject: [PATCH] [VIRTIO] Add virtio_reset callback

Call it when the driver sets the pfn to zero and
also on qemu_reset notifier list.
This fixes crashes when virtio driver unloads or when
rebooting the guest.

Signed-off-by: Dor Laor <dor.laor@xxxxxxxxxxxx>
---
qemu/hw/virtio.c |   24 +++++++++++++++++++++---
1 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/qemu/hw/virtio.c b/qemu/hw/virtio.c
index 6a1d380..e7fcfa3 100644
--- a/qemu/hw/virtio.c
+++ b/qemu/hw/virtio.c
@@ -158,6 +158,25 @@ static void virtio_update_irq(VirtIODevice *vdev)
    qemu_set_irq(vdev->pci_dev.irq[0], vdev->isr & 1);
}

+void virtio_reset(void *opaque)
+{
+    VirtIODevice *vdev = opaque;
+    int i;
+
+    vdev->features = 0;
+    vdev->queue_sel = 0;
+    vdev->status = 0;
+    vdev->isr = 0;
+
+    for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
+        vdev->vq[i].vring.desc = NULL;
+        vdev->vq[i].vring.avail = NULL;
+        vdev->vq[i].vring.used = NULL;
+        vdev->vq[i].last_avail_idx = 0;
+        vdev->vq[i].pfn = 0;
+    }
+}
+
static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val)
{
    VirtIODevice *vdev = to_virtio_device(opaque);
@@ -175,9 +194,7 @@ static void virtio_ioport_write(void *opaque, 
uint32_t addr, uint32_t val)
    pa = (ram_addr_t)val << TARGET_PAGE_BITS;
    vdev->vq[vdev->queue_sel].pfn = val;
    if (pa == 0) {
-        vdev->vq[vdev->queue_sel].vring.desc = NULL;
-        vdev->vq[vdev->queue_sel].vring.avail = NULL;
-        vdev->vq[vdev->queue_sel].vring.used = NULL;
+            virtio_reset(vdev);
    } else if (pa < (ram_size - TARGET_PAGE_SIZE)) {
        virtqueue_init(&vdev->vq[vdev->queue_sel], phys_ram_base + pa);
        /* FIXME if pa == 0, deal with device tear down */
@@ -417,6 +434,7 @@ VirtIODevice *virtio_init_pci(PCIBus *bus, const 
char *name,

    pci_register_io_region(pci_dev, 0, 20 + config_size, 
PCI_ADDRESS_SPACE_IO,
               virtio_map);
+    qemu_register_reset(virtio_reset, vdev);

    return vdev;
}
--
1.5.3.3

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