From: Sasha Levin <levinsasha928@gmail.com>
To: Avi Kivity <avi@redhat.com>
Cc: Carsten Otte <cotte@de.ibm.com>,
Marcelo Tossati <mtosatti@redhat.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Cornelia Huck <cornelia.huck@de.ibm.com>,
KVM <kvm@vger.kernel.org>,
Joachim von Buttlar <joachim_von_buttlar@de.ibm.com>,
Jens Freimann <jfrei@de.ibm.com>,
Constantin Werner <constantin.werner@de.ibm.com>,
Alexander Graf <agraf@suse.de>,
Xiantao Zhang <xiantao.zhang@intel.com>
Subject: Re: [patch 01/12] [PATCH] kvm-s390: ioctl to switch to user controlled virtual machines
Date: Thu, 08 Dec 2011 11:53:49 +0200 [thread overview]
Message-ID: <1323338029.3904.15.camel@lappy> (raw)
In-Reply-To: <4EE08721.4060701@redhat.com>
On Thu, 2011-12-08 at 11:45 +0200, Avi Kivity wrote:
> On 12/08/2011 11:25 AM, Sasha Levin wrote:
> > On Thu, 2011-12-08 at 10:12 +0100, Carsten Otte wrote:
> > > plain text document attachment (enable-ucontrol.patch)
> > > This patch introduces a new config option for user controlled kernel
> > > virtual machines. It introduces an optional parameter to
> > > KVM_CREATE_VM in order to create a user controlled virtual machine.
> > > The parameter is passed to kvm_arch_init_vm for all architectures.
> > > Valid values for the new parameter are KVM_VM_REGULAR (defined to 0
> > > for backward compatibility to old KVM_CREATE_VM) and
> > > KVM_VM_S390_UCONTROL for s390 only.
> >
> > Why is it s390 specific? why isn't it KVM_VM_UCONTROL which is currently
> > only implemented on s390?
>
> It's not possible (or at least very difficult) to implement ucontrol on
> x86. For example, to update VMCSs you need privileged instructions. It
> might be doable on svm, but there's no point, really.
Might not work for x86, but maybe on arm? ppc? or some other random arch
that will be added in the future?
No point in limiting it to s390 from day one.
It also makes code a bit cleaner (kvm_main.c shouldn't have arch names
in the code).
--
Sasha.
next prev parent reply other threads:[~2011-12-08 9:54 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-08 9:12 [patch 00/12] Ucontrol patchset V2 Carsten Otte
2011-12-08 9:12 ` [patch 01/12] [PATCH] kvm-s390: ioctl to switch to user controlled virtual machines Carsten Otte
2011-12-08 9:25 ` Sasha Levin
2011-12-08 9:27 ` Carsten Otte
2011-12-08 9:45 ` Avi Kivity
2011-12-08 9:53 ` Sasha Levin [this message]
2011-12-08 9:59 ` Avi Kivity
2011-12-08 10:18 ` Alexander Graf
2011-12-08 11:48 ` Carsten Otte
2011-12-08 13:16 ` Alexander Graf
2011-12-08 9:12 ` [patch 02/12] [PATCH] kvm-s390-ucontrol: per vcpu address spaces Carsten Otte
2011-12-08 9:12 ` [patch 03/12] [PATCH] kvm-s390-ucontrol: export page faults to user Carsten Otte
2011-12-08 9:12 ` [patch 04/12] [PATCH] kvm-s390-ucontrol: export SIE control block " Carsten Otte
2011-12-08 9:12 ` [patch 05/12] [PATCH] kvm-s390-ucontrol: disable in-kernel handling of SIE intercepts Carsten Otte
2011-12-08 9:12 ` [patch 06/12] [PATCH] kvm-s390-ucontrol: disable in-kernel irq stack Carsten Otte
2011-12-08 9:12 ` [patch 07/12] [PATCH] kvm-s390-ucontrol: interface to inject faults on a vcpu page table Carsten Otte
2011-12-08 9:12 ` [patch 08/12] [PATCH] kvm-s390-ucontrol: disable sca Carsten Otte
2011-12-08 9:12 ` [patch 09/12] [PATCH] kvm-s390: fix assumption for KVM_MAX_VCPUS Carsten Otte
2011-12-08 9:12 ` [patch 10/12] [PATCH] kvm-s390: storage key interface Carsten Otte
2011-12-08 9:12 ` [patch 11/12] [PATCH] kvm-s390-ucontrol: announce capability for user controlled vms Carsten Otte
2011-12-08 9:12 ` [patch 12/12] [PATCH] kvm-s390: Fix return code for unknown ioctl numbers Carsten Otte
-- strict thread matches above, loose matches on Subject: below --
2011-12-01 12:57 [patch 00/12] User controlled virtual machines Carsten Otte
2011-12-01 12:57 ` [patch 01/12] [PATCH] kvm-s390: ioctl to switch to user " Carsten Otte
2011-12-01 13:15 ` Avi Kivity
2011-12-01 13:31 ` Avi Kivity
2011-12-01 14:20 ` Martin Schwidefsky
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