• Amos Kong's avatar
    kvm tools: Make virt_queue__available return false if queue is not initialized · 412aa73f
    Amos Kong authored
    
    
    virtio_console__inject_interrupt tries to use virt queues before guest
    tell us to initialize them.
    
    (gdb) r run -i linux-0.2.img -k ./vmlinuz-2.6.38-rc6+ -r ./initrd.img-2.6.38-rc6+ -p=init=1 -m 500 -c
    Starting program: /project/rh/kvm-tools/tools/kvm/kvm run -i linux-0.2.img -k ./vmlinuz-2.6.38-rc6+ -r ./initrd.img-2.6.38-rc6+ -p=init=1 -m 500 -c
    [Thread debugging using libthread_db enabled]
    [New Thread 0x7fffd6e2d700 (LWP 19280)]
      Warning: request type 8
    
    Program received signal SIGSEGV, Segmentation fault.
    0x00000000004026ca in virt_queue__available (vq=0x60d3c8) at include/kvm/virtio.h:31
    31              return vq->vring.avail->idx !=  vq->last_avail_idx;
    (gdb)
    (gdb) bt
    (gdb) p *vq
    $2 = {vring = {num = 0, desc = 0x0, avail = 0x0, used = 0x0}, pfn = 0, last_avail_idx = 0}
    
    include/kvm/virtio-console.h:
     59 void virtio_console__inject_interrupt(struct kvm *self)
    ....
     71         if (term_readable(CONSOLE_VIRTIO) && virt_queue__available(vq)) {
     72                 head = virt_queue__get_iov(vq, iov, &out, &in, self);
                               ^^^^ then this block will not be executed if
                                    virtio_queue is unavaiable.
    
    Changes from v1:
    - move the check of virt_queue out of virt_queue__get_iov()
    
    Reported-by: default avatarAmos Kong <akong@redhat.com>
    Acked-by: default avatarCyrill Gorcunov <gorcunov@gmail.com>
    Signed-off-by: default avatarAsias He <asias.hejun@gmail.com>
    Signed-off-by: default avatarAmos Kong <akong@redhat.com>
    Signed-off-by: default avatarPekka Enberg <penberg@kernel.org>
    412aa73f