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From: Paolo Bonzini <pbonzini@redhat.com>
To: Wei Huang <huangwei.virt@gmail.com>, kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, jan.kiszka@siemens.com,
	gleb@kernel.org, avi.kivity@gmail.com
Subject: Re: [PATCH v2 0/4] KVM: x86: get CPL from SS.DPL
Date: Mon, 26 May 2014 14:53:24 +0200	[thread overview]
Message-ID: <53833944.6030605@redhat.com> (raw)
In-Reply-To: <CALeycy-hH7=S5tLo1TWQTqGpwsjjx6_c3yaJZs0Vywyv-fZQaQ@mail.gmail.com>

Il 26/05/2014 00:58, Wei Huang ha scritto:
> If so , my question: is there other special cases similar to task switch
> which can break patch 4?

I don't think so.  CPL can only change when SS is loaded, i.e. for 
inter-privilege transfers that aren't far calls or far jumps to a 
conforming code segment.

I count only three such cases (protected mode int, protected mode iret, 
call gate), none of which is implemented in the KVM emulator.  In fact, 
the emulator doesn't implement task gates either---luckily all 
information about the destination task is provided by the processor in 
the VMCB or VMCS.

Paolo

  reply	other threads:[~2014-05-26 12:53 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CALeycy_8q9jcbwCGp6qpcN8TyH7Ve2WUxCbo+kcd_bHYzXDqOA@mail.gmail.com>
2014-05-25 22:58 ` [PATCH v2 0/4] KVM: x86: get CPL from SS.DPL Wei Huang
2014-05-26 12:53   ` Paolo Bonzini [this message]
2014-05-15 16:51 Paolo Bonzini

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