linux-kernel - Re: [PATCH 1/1] KVM: arm64: Make nVHE ASLR conditional on nokaslr

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Message-ID:
 <SEZPR04MB63194C0FCB4765A8ABF4A2709E9E2@SEZPR04MB6319.apcprd04.prod.outlook.com>
Date: Fri, 6 Sep 2024 07:19:07 +0000
From: Qixiang Xu <qixiang.xu@...look.com>
To: Marc Zyngier <maz@...nel.org>
CC: "oliver.upton@...ux.dev" <oliver.upton@...ux.dev>, "will@...nel.org"
	<will@...nel.org>, "linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "kvmarm@...ts.linux.dev"
	<kvmarm@...ts.linux.dev>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/1] KVM: arm64: Make nVHE ASLR conditional on nokaslr

Marc,

Thanks for your reply. 

> This is a change in behaviour that would leave the 2 implementations
> affected by Spectre-v3a unmitigated and leaking information to
> *guests*, while they would have been safe until this change. Is this
> what we really want to do?

The reason for adding this is to make debugging nvhe hyp code easier. 
Otherwise, we would need to calculate the offset every time.
Do you have any better suggestions for the debugging?

> This is also not disabling the whole thing, since we still do the
> indirect vector dance.

I'm not sure if my understanding is correct, but based on 
the hyp_map_vectors function, the address of the indirect vector
is only related to __io_map_base and is not random.

Thanks. 
Qixiang Xu