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Re: [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?
From: |
hrg |
Subject: |
Re: [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache? |
Date: |
Sun, 9 Apr 2017 23:55:20 +0800 |
On Sun, Apr 9, 2017 at 11:52 PM, hrg <address@hidden> wrote:
> Hi,
>
> In xen_map_cache_unlocked(), map to guest memory maybe in entry->next
> instead of first level entry (if map to rom other than guest memory
> comes first), while in xen_invalidate_map_cache(), when VM ballooned
> out memory, qemu did not invalidate cache entries in linked
> list(entry->next), so when VM balloon back in memory, gfns probably
> mapped to different mfns, thus if guest asks device to DMA to these
> GPA, qemu may DMA to stale MFNs.
>
> So I think in xen_invalidate_map_cache() linked lists should also be
> checked and invalidated.
>
> What’s your opinion? Is this a bug? Is my analyze correct?
Added Jun Nakajima and Alexander Graf
- [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?, hrg, 2017/04/09
- Re: [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?,
hrg <=
- Re: [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?, hrg, 2017/04/09
- Re: [Qemu-devel] [Xen-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?, Alexey G, 2017/04/09
- Re: [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?, Stefano Stabellini, 2017/04/10
- Re: [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?, Stefano Stabellini, 2017/04/10
- Re: [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?, hrg, 2017/04/11
- Re: [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?, Stefano Stabellini, 2017/04/11
- Re: [Qemu-devel] [Xen-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?, Alexey G, 2017/04/12
- Re: [Qemu-devel] [Xen-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?, Herongguang (Stephen), 2017/04/12
- Re: [Qemu-devel] [Xen-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?, Stefano Stabellini, 2017/04/12
- Re: [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?, Herongguang (Stephen), 2017/04/12