Re: [PATCH v4 1/3] memory: drop guest writes to read-only ram device regions

[Philippe Mathieu-Daudé]

On 4/27/20 11:15 AM, Yan Zhao wrote:
> On Sun, Apr 26, 2020 at 09:04:31AM +0800, Yan Zhao wrote:
> > On Sat, Apr 25, 2020 at 06:55:33PM +0800, Paolo Bonzini wrote:
> > > On 17/04/20 09:44, Yan Zhao wrote:
> > > > for ram device regions, drop guest writes if the regions is read-only.
> > > >
> > > > Cc: Philippe Mathieu-Daudé <address@hidden>
> > > > Signed-off-by: Yan Zhao <address@hidden>
> > > > Signed-off-by: Xin Zeng <address@hidden>
> > > > ---
> > > >   memory.c | 7 +++++++
> > > >   1 file changed, 7 insertions(+)
> > > >
> > > > diff --git a/memory.c b/memory.c
> > > > index 601b749906..9576dd6807 100644
> > > > --- a/memory.c
> > > > +++ b/memory.c
> > > > @@ -34,6 +34,7 @@
> > > >   #include "sysemu/accel.h"
> > > >   #include "hw/boards.h"
> > > >   #include "migration/vmstate.h"
> > > > +#include "qemu/log.h"
> > > >   
> > > >   //#define DEBUG_UNASSIGNED
> > > >   
> > > > @@ -1313,6 +1314,12 @@ static void memory_region_ram_device_write(void *opaque, hwaddr addr,
> > > >       MemoryRegion *mr = opaque;
> > > >   
> > > >       trace_memory_region_ram_device_write(get_cpu_index(), mr, addr, data, size);
> > > > +    if (mr->readonly) {
> > > > +        qemu_log_mask(LOG_GUEST_ERROR,
> > > > +                      "Invalid write to read only ram device region 0x%"
> > > > +                       HWADDR_PRIx" size %u\n", addr, size);
> > > > +        return;
> > > > +    }
> > >
> > > As mentioned in the review of v1, memory_region_ram_device_write should
> > > be changed to a .write_with_attrs operation, so that it can return
> > > MEMTX_ERROR.
> hi Paolo and Alex,
> need I also change vfio_region_write() in patch 2 to a .write_with_attrs
> operation?
> vfio_region_read() is also possible to fail, so should I change it to a
> .read_with_attrs, too?

Yes.

Please submit your series as a thread, with a cover letter:
https://wiki.qemu.org/Contribute/SubmitAPatch#Include_a_meaningful_cover_letter

> Thanks
> Yan
>
> > > Otherwise this looks good.
> > hi Paolo,
> > thanks for pointing it out again!
> > I didn't get your meaning in v1. will update the patch!
> >
> > Thanks
> > Yan
> > >