Re: [PATCH] hw: ide: check the pointer before do dma memory unmap

[Li Qiang]

Ping!

Li Qiang <liq3ea@gmail.com> 于2020年9月1日周二 下午6:34写道：
>
> Ping.
>
> Li Qiang <liq3ea@163.com> 于2020年8月15日周六 下午3:21写道：
> >
> > In 'map_page' we need to check the return value of
> > 'dma_memory_map' to ensure the we actully maped something.
> > Otherwise, we will hit an assert in 'address_space_unmap'.
> > This is because we can't find the MR with the NULL buffer.
> > This is the LP#1884693:
> >
> > -->https://bugs.launchpad.net/qemu/+bug/1884693
> >
> > Reported-by: Alexander Bulekov <alxndr@bu.edu>
> > Signed-off-by: Li Qiang <liq3ea@163.com>
> > ---
> >  hw/ide/ahci.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
> > index 009120f88b..63e9fccdbe 100644
> > --- a/hw/ide/ahci.c
> > +++ b/hw/ide/ahci.c
> > @@ -250,6 +250,11 @@ static void map_page(AddressSpace *as, uint8_t **ptr, 
> > uint64_t addr,
> >      }
> >
> >      *ptr = dma_memory_map(as, addr, &len, DMA_DIRECTION_FROM_DEVICE);
> > +
> > +    if (!*ptr) {
> > +        return;
> > +    }
> > +
> >      if (len < wanted) {
> >          dma_memory_unmap(as, *ptr, len, DMA_DIRECTION_FROM_DEVICE, len);
> >          *ptr = NULL;
> > --
> > 2.17.1
> >