Commit 8eca6b1b authored by Anthony Liguori's avatar Anthony Liguori
Browse files

Fix oops on 2.6.25 guest (Rusty Russell) 

I believe this is behind the following:
https://bugs.edge.launchpad.net/ubuntu/jaunty/+source/linux/+bug/331128



virtio_pci in 2.6.25 didn't do feature negotiation correctly: it acked every
bit.  Fortunately, we can detect this.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6975 c046a42c-6fe2-441c-8c8c-71466251a162
parent 1da92db2

hw/virtio-net.c

+16 −0
Original line number Diff line number Diff line
@@ -113,6 +113,21 @@ static uint32_t virtio_net_get_features(VirtIODevice *vdev) 
    return features;

}



static uint32_t virtio_net_bad_features(VirtIODevice *vdev)

{

    uint32_t features = 0;



    /* Linux kernel 2.6.25.  It understood MAC (as everyone must),

     * but also these: */

    features |= (1 << VIRTIO_NET_F_MAC);

    features |= (1 << VIRTIO_NET_F_GUEST_CSUM);

    features |= (1 << VIRTIO_NET_F_GUEST_TSO4);

    features |= (1 << VIRTIO_NET_F_GUEST_TSO6);

    features |= (1 << VIRTIO_NET_F_GUEST_ECN);



    return features & virtio_net_get_features(vdev);

}



static void virtio_net_set_features(VirtIODevice *vdev, uint32_t features)

{

    VirtIONet *n = to_virtio_net(vdev);
@@ -580,6 +595,7 @@ PCIDevice *virtio_net_init(PCIBus *bus, NICInfo *nd, int devfn) 
    n->vdev.set_config = virtio_net_set_config;

    n->vdev.get_features = virtio_net_get_features;

    n->vdev.set_features = virtio_net_set_features;

    n->vdev.bad_features = virtio_net_bad_features;

    n->vdev.reset = virtio_net_reset;

    n->rx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_rx);

    n->tx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_tx);

hw/virtio.c

+8 −1
Original line number Diff line number Diff line
@@ -451,6 +451,13 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val) 


    switch (addr) {

    case VIRTIO_PCI_GUEST_FEATURES:

	/* Guest does not negotiate properly?  We have to assume nothing. */

	if (val & (1 << VIRTIO_F_BAD_FEATURE)) {

	    if (vdev->bad_features)

		val = vdev->bad_features(vdev);

	    else

		val = 0;

	}

        if (vdev->set_features)

            vdev->set_features(vdev, val);

        vdev->features = val;
@@ -490,7 +497,7 @@ static uint32_t virtio_ioport_read(void *opaque, uint32_t addr) 
    switch (addr) {

    case VIRTIO_PCI_HOST_FEATURES:

        ret = vdev->get_features(vdev);

        ret |= (1 << VIRTIO_F_NOTIFY_ON_EMPTY);

        ret |= (1 << VIRTIO_F_NOTIFY_ON_EMPTY) | (1 << VIRTIO_F_BAD_FEATURE);

        break;

    case VIRTIO_PCI_GUEST_FEATURES:

        ret = vdev->features;

hw/virtio.h

+3 −0
Original line number Diff line number Diff line
@@ -32,6 +32,8 @@ 
/* We notify when the ring is completely used, even if the guest is supressing

 * callbacks */

#define VIRTIO_F_NOTIFY_ON_EMPTY        24

/* A guest should never accept this.  It implies negotiation is broken. */

#define VIRTIO_F_BAD_FEATURE		30



/* from Linux's linux/virtio_ring.h */
@@ -82,6 +84,7 @@ struct VirtIODevice 
    size_t config_len;

    void *config;

    uint32_t (*get_features)(VirtIODevice *vdev);

    uint32_t (*bad_features)(VirtIODevice *vdev);

    void (*set_features)(VirtIODevice *vdev, uint32_t val);

    void (*get_config)(VirtIODevice *vdev, uint8_t *config);

    void (*set_config)(VirtIODevice *vdev, const uint8_t *config);