From mboxrd@z Thu Jan  1 00:00:00 1970
From: Gleb Natapov <gleb@redhat.com>
Subject: Re: [PATCH] KVM: unbreak userspace that does not sets tss address
Date: Mon, 7 Mar 2011 18:20:30 +0200
Message-ID: <20110307162030.GB22987@redhat.com>
References: <20110307151936.GA10151@redhat.com>
 <4D74FE88.9060708@siemens.com>
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To: Jan Kiszka <jan.kiszka@siemens.com>
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On Mon, Mar 07, 2011 at 04:49:28PM +0100, Jan Kiszka wrote:
> On 2011-03-07 16:19, Gleb Natapov wrote:
> > Commit 6440e5967bc broke old userspaces that do not set tss address
> > before entering vcpu. Unbreak it by setting tss address to a safe
> > value on the first vcpu entry. New userspaces should set tss address,
> > so print warning in case it doesn't.
> 
> Wouldn't allow runtime warnings but wouldn't it be cleaner otherwise to
> start vcpus with a default tss address like that, ie. add the logic to
> vmx_create_vcpu?
> 
Userspace can create VCPU before setting tss address. We will have to
have logic that removes default tss slot in set_tss_address callback.
Also this default slot may prevent userspace from creating another slot
at this physical address which is perfectly legitimate thing for userspace
to do.

--
			Gleb.