From: hrg <hrgstephen@gmail.com>
To: stefano.stabellini@eu.citrix.com, anthony.perard@citrix.com,
xen-devel@lists.xensource.com, qemu-devel@nongnu.org,
jun.nakajima@intel.com, agraf@suse.de
Cc: xen-devel@lists.xenproject.org, xen-devel@lists.xen.org,
"Herongguang (Stephen)" <herongguang.he@huawei.com>,
wangxinxin.wang@huawei.com
Subject: Re: [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache?
Date: Sun, 9 Apr 2017 23:55:20 +0800 [thread overview]
Message-ID: <CADZi59xe6OcCasvtkPBjP7nTsgDA5r_E_Rt7W88BszYdJhuxGQ@mail.gmail.com> (raw)
In-Reply-To: <CADZi59zNxk-Yr4rpN1E49s=AdsdW-W9YfhpCvpJeBz7oigyFSg@mail.gmail.com>
On Sun, Apr 9, 2017 at 11:52 PM, hrg <hrgstephen@gmail.com> 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
next prev parent reply other threads:[~2017-04-09 15:55 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-09 15:52 [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache? hrg
2017-04-09 15:55 ` hrg [this message]
2017-04-09 16:36 ` hrg
2017-04-09 17:52 ` [Qemu-devel] [Xen-devel] " Alexey G
2017-04-10 19:04 ` [Qemu-devel] " Stefano Stabellini
2017-04-10 19:50 ` Stefano Stabellini
2017-04-11 4:47 ` hrg
2017-04-11 22:32 ` Stefano Stabellini
2017-04-12 6:17 ` [Qemu-devel] [Xen-devel] " Alexey G
2017-04-12 8:28 ` Herongguang (Stephen)
2017-04-12 23:51 ` Stefano Stabellini
2017-04-12 8:14 ` [Qemu-devel] " Herongguang (Stephen)
2017-04-12 23:51 ` Stefano Stabellini
2017-04-13 5:47 ` Herongguang (Stephen)
2017-04-28 23:51 ` Stefano Stabellini
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