Patchwork scp during migration with vhost fails

On Sat, Feb 23, 2013 at 11:54:55PM +0200, Michael S. Tsirkin wrote:
> On Sat, Feb 23, 2013 at 10:49:29PM +0200, Michael S. Tsirkin wrote:
> > On Fri, Feb 22, 2013 at 11:33:53PM +0800, Jason Wang wrote:
> > > On 02/21/2013 07:23 PM, Michael S. Tsirkin wrote:
> > > > On Thu, Feb 21, 2013 at 05:57:04PM +0800, Jason Wang wrote:
> > > >> On 02/21/2013 12:48 AM, Michael S. Tsirkin wrote:
> > > >>> On Wed, Feb 20, 2013 at 04:23:52PM +0200, Michael S. Tsirkin wrote:
> > > >>>> On Fri, Feb 01, 2013 at 06:03:32PM +0800, Jason Wang wrote:
> > > >>>>> Hello all:
> > > >>>>>
> > > >>>>> During testing, I find doing scp during migration with vhost fails with 
> > > >>>>> warnings in guest like:
> > > >>>>>
> > > >>>>> Corrupted MAC on input.
> > > >>>>> Disconnecting: Packet corrupt.
> > > >>>>> lost connection
> > > >>>>>
> > > >>>>> Here's the bisect result:
> > > >>>>>
> > > >>>>> Commit a01672d3968cf91208666d371784110bfde9d4f8 kvm: convert to MemoryListener 
> > > >>>>> API is the last commit that works well.
> > > >>>>>
> > > >>>>> With commit 04097f7c5957273c578f72b9bd603ba6b1d69e33 vhost: convert to 
> > > >>>>> MemoryListener API, guest network is unusable with warning of "bad gso type"
> > > >>>>>
> > > >>>>> With commit d743c382861eaa1e13f503b05aba5a382a7e7f7c vhost: fix incorrect 
> > > >>>>> userspace address, guest network is available, but scp during migration may 
> > > >>>>> fail.
> > > >>>>>
> > > >>>>> Looks like the issue is related to memory api, any thoughts?
> > > >>>>>
> > > >>>>> Thanks
> > > >>>> Tried to reproduce this for a while without success.
> > > >>>> Which command line was used?
> > > >>>>
> > > >>>>
> > > >>>> -- 
> > > >>>> MST
> > > >>> Could be we are not syncing all that we should?
> > > >>> Does the following hack make the problem go away?
> > > >>>
> > > >>> diff --git a/hw/vhost.c b/hw/vhost.c
> > > >>> index 8d41fdb..a7a0412 100644
> > > >>> --- a/hw/vhost.c
> > > >>> +++ b/hw/vhost.c
> > > >>> @@ -69,6 +69,8 @@ static int vhost_sync_dirty_bitmap(struct vhost_dev *dev,
> > > >>>                                     hwaddr end_addr)
> > > >>>  {
> > > >>>      int i;
> > > >>> +    start_addr = 0x0;
> > > >>> +    end_addr = ~0x0ull;
> > > >>>  
> > > >>>      if (!dev->log_enabled || !dev->started) {
> > > >>>          return 0;
> > > >>>
> > > >> Still can reproduce with this. From the bisect result, the vhost dirty
> > > >> bitmap sync itself looks ok but something wrong when converting to
> > > >> memory listener.
> > > > Reading the code carefully, I found two bugs introduced during
> > > > this conversion. Patch below, could you please try?
> > > >
> > > >     vhost: memory sync fixes
> > > >     
> > > >     This fixes two bugs related to memory sync during
> > > >     migration:
> > > >         - ram address calculation was missing the chunk
> > > >           address, so the wrong page was dirtied
> > > >         - one after last was used instead of the
> > > >           end address of a region, which might overflow to 0
> > > >           and cause us to skip the region when the region ends at
> > > >           ~0x0ull.
> > > >     
> > > >     Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > > >
> > > > ---
> > > >
> > > > diff --git a/hw/vhost.c b/hw/vhost.c
> > > > index 8d41fdb..dbf6b46 100644
> > > > --- a/hw/vhost.c
> > > > +++ b/hw/vhost.c
> > > > @@ -55,7 +55,7 @@ static void vhost_dev_sync_region(struct vhost_dev *dev,
> > > >                  ffsll(log) : ffs(log))) {
> > > >              ram_addr_t ram_addr;
> > > >              bit -= 1;
> > > > -            ram_addr = section->offset_within_region + bit * VHOST_LOG_PAGE;
> > > > +            ram_addr = section->offset_within_region + addr + bit * VHOST_LOG_PAGE;
> > > >              memory_region_set_dirty(section->mr, ram_addr, VHOST_LOG_PAGE);
> > > >              log &= ~(0x1ull << bit);
> > > >          }
> > > > @@ -94,7 +94,7 @@ static void vhost_log_sync(MemoryListener *listener,
> > > >      struct vhost_dev *dev = container_of(listener, struct vhost_dev,
> > > >                                           memory_listener);
> > > >      hwaddr start_addr = section->offset_within_address_space;
> > > > -    hwaddr end_addr = start_addr + section->size;
> > > > +    hwaddr end_addr = start_addr + section->size - 1;
> > > >  
> > > >      vhost_sync_dirty_bitmap(dev, section, start_addr, end_addr);
> > > >  }
> > > >
> > > 
> > > I can still reproduce the issue with this patch.
> > 
> > 
> > Yes it's still wrong. We need the following on top.
> > Could you try please?
> > 
> > diff --git a/hw/vhost.c b/hw/vhost.c
> > index dbf6b46..c324903 100644
> > --- a/hw/vhost.c
> > +++ b/hw/vhost.c
> > @@ -29,7 +29,7 @@ static void vhost_dev_sync_region(struct vhost_dev *dev,
> >      uint64_t end = MIN(mlast, rlast);
> >      vhost_log_chunk_t *from = dev->log + start / VHOST_LOG_CHUNK;
> >      vhost_log_chunk_t *to = dev->log + end / VHOST_LOG_CHUNK + 1;
> > -    uint64_t addr = (start / VHOST_LOG_CHUNK) * VHOST_LOG_CHUNK;
> > +    uint64_t addr = 0;
> >  
> >      if (end < start) {
> >          return;
> 
> 
> Sorry, scratch that last one, sorry.
> This should be the right thing, I think: on top of
> 'vhost: memory sync fixes'.
> 
> diff --git a/hw/vhost.c b/hw/vhost.c
> index dbf6b46..72c0095 100644
> --- a/hw/vhost.c
> +++ b/hw/vhost.c
> @@ -53,9 +53,10 @@ static void vhost_dev_sync_region(struct vhost_dev *dev,
>          log = __sync_fetch_and_and(from, 0);
>          while ((bit = sizeof(log) > sizeof(int) ?
>                  ffsll(log) : ffs(log))) {
> -            ram_addr_t ram_addr;
> +            hwaddr ram_addr;
>              bit -= 1;
> -            ram_addr = section->offset_within_region + addr + bit * VHOST_LOG_PAGE;
> +            ram_addr = addr + bit * VHOST_LOG_PAGE -
> +                section->mr->offset_within_address_space;
>              memory_region_set_dirty(section->mr, ram_addr, VHOST_LOG_PAGE);
>              log &= ~(0x1ull << bit);
>          }
> 


OK try 3 - does it work?


Signed-off-by: Michael S. Tsirkin <mst@redhat.com>