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From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
	Andrew Cooper <andrew.cooper3@citrix.com>, Wei Liu <wl@xen.org>
Subject: Re: [PATCH v2] x86emul: de-duplicate scatters to the same linear address
Date: Mon, 18 Oct 2021 13:19:55 +0200	[thread overview]
Message-ID: <YW1YW8HJr6ttyd84@MacBook-Air-de-Roger.local> (raw)
In-Reply-To: <cf935e11-27c8-969f-9fb2-a5c0e85ccff1@suse.com>

On Thu, May 20, 2021 at 03:34:28PM +0200, Jan Beulich wrote:
> The SDM specifically allows for earlier writes to fully overlapping
> ranges to be dropped. If a guest did so, hvmemul_phys_mmio_access()
> would crash it if varying data was written to the same address. Detect
> overlaps early, as doing so in hvmemul_{linear,phys}_mmio_access() would
> be quite a bit more difficult. To maintain proper faulting behavior,
> instead of dropping earlier write instances of fully overlapping slots
> altogether, write the data of the final of these slots multiple times.

Is it possible for a later (non duplicated slot) to cause a fault
ending the instruction without reaching that final slot that contains
the written data?

Thanks, Roger.


  parent reply	other threads:[~2021-10-18 11:20 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-20 13:34 [PATCH v2] x86emul: de-duplicate scatters to the same linear address Jan Beulich
2021-06-28 12:13 ` Ping: " Jan Beulich
2021-10-18  8:10   ` Ping²: " Jan Beulich
2021-10-18 11:19 ` Roger Pau Monné [this message]
2021-10-18 12:17   ` Jan Beulich
2021-10-18 12:52     ` Roger Pau Monné

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