Re: [Qemu-devel] [PATCH] vhost: fix log base address

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Apr 17, 2015 at 03:40:50PM +0100, Peter Maydell wrote:
> On 16 April 2015 at 22:26, Paolo Bonzini <pbonzini@redhat.com> wrote:
> >
> >
> > On 15/04/2015 11:56, zhanghailiang wrote:
> >> On 2015/4/15 17:37, Michael S. Tsirkin wrote:
> >>> VHOST_SET_LOG_BASE got an incorrect address, causing
> >>> migration errors and potentially even memory corruption.
> >>>
> >>> Cc: Peter Maydell <peter.maydell@linaro.org>
> >>> Reported-by: Wen Congyang <wency@cn.fujitsu.com>
> >>> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> >>> ---
> >>>
> >>> Could you please confirm this fixes the problem for you?
> >>>
> >>>   hw/virtio/vhost.c | 5 ++++-
> >>>   1 file changed, 4 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> >>> index 8dd2f59..02c5604 100644
> >>> --- a/hw/virtio/vhost.c
> >>> +++ b/hw/virtio/vhost.c
> >>> @@ -1016,10 +1016,13 @@ int vhost_dev_start(struct vhost_dev *hdev,
> >>> VirtIODevice *vdev)
> >>>       }
> >>>
> >>>       if (hdev->log_enabled) {
> >>> +        uint64_t log_base;
> >>> +
> >>>           hdev->log_size = vhost_get_log_size(hdev);
> >>>           hdev->log = hdev->log_size ?
> >>>               g_malloc0(hdev->log_size * sizeof *hdev->log) : NULL;
> >>> -        r = hdev->vhost_ops->vhost_call(hdev, VHOST_SET_LOG_BASE,
> >>> hdev->log);
> >>> +        log_base = (uint64_t)(unsigned long)log_base;
> >>                                                ^^^^^^^^
> >>
> >> s/log_base/hdev->log ?
> >
> > Also s/unsigned long/uintptr_t/ please.  The subsequent cast to uint64_t
> > is not necessary.
> 
> I think this is our remaining for-2.3 bug; would somebody like
> to produce and test a patch with all the fixes mentioned in
> this thread?
> 
> thanks
> -- PMM

I just posted it but it's not tested yet.