From: Josh Poimboeuf <jpoimboe@redhat.com>
To: speck@linutronix.de
Subject: [MODERATED] Re: LVI
Date: Tue, 19 Nov 2019 12:27:52 -0600 [thread overview]
Message-ID: <20191119182752.xh5e6x733nnhjwo5@treble> (raw)
In-Reply-To: <e1053049-565d-1f92-812c-f54f6a23059f@citrix.com>
On Tue, Nov 19, 2019 at 05:51:40PM +0000, speck for Andrew Cooper wrote:
> On 19/11/2019 17:40, speck for Josh Poimboeuf wrote:
> > Hi,
> >
> > What kernel changes (if any) are needed for LVI? I haven't seen any
> > discussion here.
>
> I have similar questions when it comes to virt. For one, EPT A/D bits
> undermine any action the guest kernel takes to protect itself.
>
> Given various pieces of academic literature on gaming the paging-out
> algorithm, I'm not inclined to take the bet that an attacker couldn't
> control EPT A/D bits to their advantage.
Hm, so IIUC, that would open up every load in the guest to a potential
attack, if it has gadgets after it? That does sound bad...
If the A/D bit control is feasible then it sounds like we'd need an
L1TF-like flushing mitigation after vmexit? That would protect the host
kernel too.
For L1TF-affected systems would it be feasible to move the vmenter
flushing to vmexit? Or would we need both?
--
Josh
next prev parent reply other threads:[~2019-11-19 18:28 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-19 17:40 [MODERATED] LVI Josh Poimboeuf
2019-11-19 17:51 ` [MODERATED] LVI Andrew Cooper
2019-11-19 18:27 ` Josh Poimboeuf [this message]
2019-11-19 19:26 ` Andrew Cooper
2019-11-20 9:52 ` Paolo Bonzini
2019-11-19 18:12 ` Greg KH
2019-11-19 18:21 ` Josh Poimboeuf
2019-11-19 18:46 ` Greg KH
2019-11-19 18:21 ` Paolo Bonzini
2019-11-19 18:22 ` Andrew Cooper
2019-11-19 18:27 ` Josh Poimboeuf
2019-11-19 18:36 ` Luck, Tony
2019-11-20 17:02 ` Greg KH
2019-11-19 18:39 ` Andrew Cooper
2019-11-19 21:00 ` Josh Poimboeuf
2019-11-19 21:03 ` Josh Poimboeuf
2019-11-20 14:11 ` Andrew Cooper
2019-11-20 8:04 ` Peter Zijlstra
2019-11-20 9:49 ` Andrew Cooper
2019-11-20 17:13 ` Josh Poimboeuf
2019-11-20 17:25 ` Greg KH
2019-11-20 17:29 ` Tyler Hicks
2019-11-20 17:30 ` Andrew Cooper
2019-11-20 17:46 ` Greg KH
2019-11-20 19:09 ` Peter Zijlstra
2019-11-20 19:19 ` Greg KH
2019-11-21 0:50 ` LVI Thomas Gleixner
2019-11-21 13:45 ` [MODERATED] LVI Greg KH
2019-11-26 0:54 ` Andi Kleen
2019-11-26 10:37 ` Greg KH
2019-11-26 18:23 ` Andi Kleen
2019-11-27 7:38 ` Greg KH
2019-11-26 10:55 ` Paolo Bonzini
2019-11-26 18:28 ` Andi Kleen
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