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From: "Michael S. Tsirkin" <mst@redhat.com>
To: qemu-devel@nongnu.org
Cc: Jason Wang <jasowang@redhat.com>
Subject: [Qemu-devel] virtio 1 issues
Date: Fri, 7 Aug 2015 01:31:21 +0300	[thread overview]
Message-ID: <20150807012346-mutt-send-email-mst@redhat.com> (raw)

Going over the code, I found a couple of issues.
Recording them here since I won't be able to work
on them until after the forum.


1. I realized we don't save/restore
serialize the following fields in virtio pci:

    uint32_t dfselect;
    uint32_t gfselect;
    uint32_t guest_features[2];
    struct {
        uint16_t num;
        bool enabled;
        uint32_t desc[2];
        uint32_t avail[2];
        uint32_t used[2];
    } vqs[VIRTIO_QUEUE_MAX];

This isn't an issue unless VM is migrated during driver initialization.

2. ring resizing is broken - it actually has a comment:
        /* TODO: need a way to put num back on reset. */
guest that runs out of memory might down-size the ring.
Afterwards, ring size won't come back up after reset - not nice.



Given that the modern layout is disabled by default,
I don't think these are release blockers.

-- 
MST

             reply	other threads:[~2015-08-06 22:44 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-06 22:31 Michael S. Tsirkin [this message]
2015-08-07  5:07 ` [Qemu-devel] virtio 1 issues Jason Wang
2015-08-07 10:49   ` Cornelia Huck
2015-08-10  6:22     ` Jason Wang
2015-08-10 15:32       ` Cornelia Huck

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