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From: "Michael S. Tsirkin" <mst@redhat.com>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: pair@us.ibm.com, "Daniel P. Berrangé" <berrange@redhat.com>,
	aik@ozlabs.ru, groug@kaod.org, qemu-devel@nongnu.org,
	paulus@samba.org, clg@kaod.org, mdroth@us.ibm.com,
	qemu-ppc@nongnu.org
Subject: Re: Upstream QEMU guest support policy ? Re: [PATCH v3 0/2] spapr: Use vIOMMU translation for virtio by default
Date: Thu, 12 Mar 2020 02:32:11 -0400	[thread overview]
Message-ID: <20200312023041-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20200312011049.GC711223@umbus.fritz.box>

On Thu, Mar 12, 2020 at 12:10:49PM +1100, David Gibson wrote:
> On Wed, Mar 11, 2020 at 03:33:59AM -0400, Michael S. Tsirkin wrote:
> > On Wed, Mar 11, 2020 at 12:12:47PM +1100, David Gibson wrote:
> > > I am wondering if we have to introduce an "svm=on" flag anyway.  It's
> > > pretty ugly, since all it would be doing is changing defaults here and
> > > there for compatibilty with a possible future SVM transition, but
> > > maybe it's the best we can do :/.
> > 
> > Frankly I'm surprised there's no way for the hypervisor to block VM
> > transition to secure mode. To me an inability to disable DRM looks like
> > a security problem.
> 
> Uh.. I don't immediately see how it's a security problem, though I'm
> certainly convinced it's a problem in other ways.

Well for one it breaks introspection, allowing guests to hide
malicious code from hypervisors.

> > Does not the ultravisor somehow allow
> > enabling/disabling this functionality from the hypervisor?
> 
> Not at present, but as mentioned on the other thread, Paul and I came
> up with a tentative plan to change that.
> 
> > It would be
> > even better if the hypervisor could block the guest from poking at the
> > ultravisor completely but I guess that would be too much to hope for.
> 
> Yeah, probably :/.
> 
> -- 
> David Gibson			| I'll have my music baroque, and my code
> david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
> 				| _way_ _around_!
> http://www.ozlabs.org/~dgibson




  reply	other threads:[~2020-03-12  6:33 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-05  4:30 [PATCH v3 0/2] spapr: Use vIOMMU translation for virtio by default David Gibson
2020-03-05  4:30 ` [PATCH v3 1/2] spapr: Disable legacy virtio devices for pseries-5.0 and later David Gibson
2020-03-05 10:31   ` Greg Kurz
2020-03-10  9:43     ` Greg Kurz
2020-03-10  9:57       ` Michael S. Tsirkin
2020-03-10 11:03       ` Michael S. Tsirkin
2020-03-10 12:24         ` Greg Kurz
2020-03-10 11:56   ` Daniel P. Berrangé
2020-03-11  0:58     ` David Gibson
2020-03-11  7:11       ` Michael S. Tsirkin
2020-03-12  1:14         ` David Gibson
2020-03-12  6:41           ` Michael S. Tsirkin
2020-03-05  4:30 ` [PATCH v3 2/2] spapr: Enable virtio iommu_platform=on by default David Gibson
2020-03-05 11:59   ` Greg Kurz
2020-03-10 10:43     ` Greg Kurz
2020-03-12  4:14       ` Alexey Kardashevskiy
2020-03-12  8:02         ` Greg Kurz
2020-03-10 11:43 ` Upstream QEMU guest support policy ? Re: [PATCH v3 0/2] spapr: Use vIOMMU translation for virtio " Daniel P. Berrangé
2020-03-11  1:12   ` David Gibson
2020-03-11  7:33     ` Michael S. Tsirkin
2020-03-12  1:10       ` David Gibson
2020-03-12  6:32         ` Michael S. Tsirkin [this message]
2020-03-16  3:06           ` David Gibson
2020-03-11 10:01     ` Daniel P. Berrangé
2020-03-11 11:48       ` Michael S. Tsirkin
2020-03-12  1:09         ` David Gibson
2020-03-12  1:08       ` David Gibson
2020-03-12  9:47         ` Daniel P. Berrangé
2020-03-11 17:19 ` Greg Kurz

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