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From: George Dunlap <george.dunlap@citrix.com>
To: Tamas K Lengyel <tamas.lengyel@zentific.com>,
	xen-devel@lists.xenproject.org
Cc: Kevin Tian <kevin.tian@intel.com>,
	Tamas K Lengyel <tamas@tklengyel.com>,
	Jan Beulich <jbeulich@suse.com>,
	Razvan Cojocaru <rcojocaru@bitdefender.com>,
	George Dunlap <george.dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Julien Grall <julien.grall@arm.com>,
	Paul Durrant <paul.durrant@citrix.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Jun Nakajima <jun.nakajima@intel.com>
Subject: Re: [RFC] x86/vm_event: Allow returning i-cache for emulation
Date: Mon, 12 Sep 2016 15:16:26 +0100	[thread overview]
Message-ID: <a72f16b3-5a1c-0aa2-636e-e0b3f289ce05@citrix.com> (raw)
In-Reply-To: <20160909154125.15976-1-tamas.lengyel@zentific.com>

On 09/09/16 16:41, Tamas K Lengyel wrote:
> When emulating instructions the emulator maintains a small i-cache fetched
> from the guest memory. Under certain scenarios this memory region may contain
> instructions that a monitor subscriber would prefer to hide, namely INT3, and
> instead would prefer to emulate a different instruction in-place.
> 
> This patch extends the vm_event interface to allow returning this i-cache via
> the vm_event response.

So do you have a problem right now with stale caches (i.e., you modify
an INT3 back to something else in guest RAM but the emulator still
emulates the INT3)?  Or is the idea here that instead of doing the
replace-singlestep-replace loop, you just tell the emulator, "Here,
emulate this instead" (without removing the INT3 from guest memory at all)?

(Or am I completely missing the point here?)

 -George


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  parent reply	other threads:[~2016-09-12 14:16 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-09 15:41 [RFC] x86/vm_event: Allow returning i-cache for emulation Tamas K Lengyel
2016-09-09 15:56 ` Razvan Cojocaru
2016-09-09 23:11 ` Stefano Stabellini
2016-09-09 23:21   ` Tamas Lengyel
2016-09-10  1:03     ` Stefano Stabellini
2016-09-12 14:16 ` George Dunlap [this message]
2016-09-12 14:31   ` Tamas Lengyel
2016-09-12 14:34     ` George Dunlap
2016-09-12 14:56 ` Jan Beulich
2016-09-12 14:59   ` George Dunlap
2016-09-12 15:04     ` Tamas Lengyel
2016-09-12 15:48   ` Tamas Lengyel
2016-09-12 16:02     ` Jan Beulich
2016-09-12 16:30       ` Tamas K Lengyel

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