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Re: [PATCH v19 QEMU 4/4] memory: Do not allow direct write access to rom
From: |
Alexander Duyck |
Subject: |
Re: [PATCH v19 QEMU 4/4] memory: Do not allow direct write access to rom_device regions |
Date: |
Mon, 13 Apr 2020 15:48:29 -0700 |
On Fri, Apr 10, 2020 at 3:50 AM Paolo Bonzini <address@hidden> wrote:
>
> On 10/04/20 05:41, Alexander Duyck wrote:
> > From: Alexander Duyck <address@hidden>
> >
> > According to the documentation in memory.h a ROM memory region will be
> > backed by RAM for reads, but is supposed to go through a callback for
> > writes. Currently we were not checking for the existence of the rom_device
> > flag when determining if we could perform a direct write or not.
> >
> > To correct that add a check to memory_region_is_direct so that if the
> > memory region has the rom_device flag set we will return false for all
> > checks where is_write is set.
> >
> > Signed-off-by: Alexander Duyck <address@hidden>
> > ---
> > include/exec/memory.h | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/exec/memory.h b/include/exec/memory.h
> > index 1614d9a02c0c..e000bd2f97b2 100644
> > --- a/include/exec/memory.h
> > +++ b/include/exec/memory.h
> > @@ -2351,8 +2351,8 @@ void
> > address_space_write_cached_slow(MemoryRegionCache *cache,
> > static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write)
> > {
> > if (is_write) {
> > - return memory_region_is_ram(mr) &&
> > - !mr->readonly && !memory_region_is_ram_device(mr);
> > + return memory_region_is_ram(mr) && !mr->readonly &&
> > + !mr->rom_device && !memory_region_is_ram_device(mr);
> > } else {
> > return (memory_region_is_ram(mr) &&
> > !memory_region_is_ram_device(mr)) ||
> > memory_region_is_romd(mr);
> >
>
> Good catch. I queued this up for 5.0.
>
> Thanks,
>
> Paolo
Thanks Paolo,
It looks like you only pulled this patch correct?
If so, David & Michael, do I need to resubmit the first 3 in this
series or can those be pulled separately?
Thanks.
Alex
- Re: [PATCH v19 QEMU 1/4] virtio-balloon: Implement support for page poison tracking feature, (continued)
[PATCH v19 QEMU 2/4] linux-headers: update to contain virito-balloon free page reporting, Alexander Duyck, 2020/04/09
[PATCH v19 QEMU 3/4] virtio-balloon: Provide an interface for free page reporting, Alexander Duyck, 2020/04/09
[PATCH v19 QEMU 4/4] memory: Do not allow direct write access to rom_device regions, Alexander Duyck, 2020/04/09