linux-kernel - Re: KVM Nested L2 guest startup problems

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <536A1AEA.9020309@redhat.com>
Date:	Wed, 07 May 2014 13:37:14 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Abel Gordon <abel@...atoscale.com>
CC:	Hu Yaohui <loki2441@...il.com>, Bandan Das <bsd@...hat.com>,
	kvm <kvm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Muli Ben-Yehuda <muli@...atoscale.com>
Subject: Re: KVM Nested L2 guest startup problems

Il 07/05/2014 13:16, Abel Gordon ha scritto:
>> > PLE should be left enabled, I think.
> Well... the PLE settings L0 uses to run  L1 (vmcs01) may be different
> than the PLE settings L1 configured to run  L2 (vmcs12).
> For example, L0 can use a  ple_gap to run L1 that is bigger than the
> ple_gap L1 configured to run L2. Or  L0 can use a ple_window to run L1
> that is smaller than the ple_window L1 configured to run L2.

That's correct.  We should leave PLE enabled while running L2, but hide 
the feature altogether from L1.

Paolo

> So seems PLE should never be exposed to L1 or an appropriate nested
> handling needs to be implemented. Note the handling may become complex
> because in some cases a PLE exit from L2 should be handled directly by
> L0 and not passed to L1... remember nested preemption timer support :)
> ?

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/