From: David Gibson <david@gibson.dropbear.id.au>
To: Cornelia Huck <cohuck@redhat.com>
Cc: Halil Pasic <pasic@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
pair@us.ibm.com, brijesh.singh@amd.com, frankja@linux.ibm.com,
kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>,
Richard Henderson <richard.henderson@linaro.org>,
Marcelo Tosatti <mtosatti@redhat.com>,
david@redhat.com, dgilbert@redhat.com,
Eduardo Habkost <ehabkost@redhat.com>,
qemu-devel@nongnu.org, qemu-s390x@nongnu.org,
qemu-ppc@nongnu.org, berrange@redhat.com, thuth@redhat.com,
pbonzini@redhat.com, rth@twiddle.net, mdroth@linux.vnet.ibm.com
Subject: Re: [for-6.0 v5 12/13] securable guest memory: Alter virtio default properties for protected guests
Date: Thu, 17 Dec 2020 16:53:38 +1100 [thread overview]
Message-ID: <20201217055338.GI310465@yekko.fritz.box> (raw)
In-Reply-To: <20201208135005.100d56fb.cohuck@redhat.com>
[-- Attachment #1: Type: text/plain, Size: 2449 bytes --]
On Tue, Dec 08, 2020 at 01:50:05PM +0100, Cornelia Huck wrote:
> On Tue, 8 Dec 2020 11:28:29 +0100
> Halil Pasic <pasic@linux.ibm.com> wrote:
>
> > On Tue, 8 Dec 2020 12:54:03 +1100
> > David Gibson <david@gibson.dropbear.id.au> wrote:
> >
> > > > > >>> + * Virtio devices can't count on directly accessing guest
> > > > > >>> + * memory, so they need iommu_platform=on to use normal DMA
> > > > > >>> + * mechanisms. That requires also disabling legacy virtio
> > > > > >>> + * support for those virtio pci devices which allow it.
> > > > > >>> + */
> > > > > >>> + object_register_sugar_prop(TYPE_VIRTIO_PCI, "disable-legacy",
> > > > > >>> + "on", true);
> > > > > >>> + object_register_sugar_prop(TYPE_VIRTIO_DEVICE, "iommu_platform",
> > > > > >>> + "on", false);
> > > > > >>
> > > > > >> I have not followed all the history (sorry). Should we also set iommu_platform
> > > > > >> for virtio-ccw? Halil?
> > > > > >>
> > > > > >
> > > > > > That line should add iommu_platform for all virtio devices, shouldn't
> > > > > > it?
> > > > >
> > > > > Yes, sorry. Was misreading that with the line above.
> > > > >
> > > >
> > > > I believe this is the best we can get. In a sense it is still a
> > > > pessimization,
> > >
> > > I'm not really clear on what you're getting at here.
> >
> > By pessimiziation, I mean that we are going to indicate
> > _F_PLATFORM_ACCESS even if it isn't necessary, because the guest never
> > opted in for confidential/memory protection/memory encryption. We have
> > discussed this before, and I don't see a better solution that works for
> > everybody.
>
> If you consider specifying the secure guest option as a way to tell
> QEMU to make everything ready for running a secure guest, I'd certainly
> consider it necessary. If you do not want to force it, you should not
> do the secure guest preparation setup.
Right, that's my feeling as well.
I'm also of the opinion that !F_PLATFORM_ACCESS is kind of a nasty
hack that has some other problems (e.g. it means an L1 can't safely
pass the device into an L2).
--
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
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WARNING: multiple messages have this Message-ID (diff)
From: David Gibson <david@gibson.dropbear.id.au>
To: Cornelia Huck <cohuck@redhat.com>
Cc: pair@us.ibm.com, brijesh.singh@amd.com, frankja@linux.ibm.com,
kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Richard Henderson <richard.henderson@linaro.org>,
dgilbert@redhat.com, qemu-devel@nongnu.org,
Halil Pasic <pasic@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
qemu-s390x@nongnu.org, qemu-ppc@nongnu.org, pbonzini@redhat.com,
thuth@redhat.com, berrange@redhat.com, david@redhat.com,
rth@twiddle.net, mdroth@linux.vnet.ibm.com,
Eduardo Habkost <ehabkost@redhat.com>
Subject: Re: [for-6.0 v5 12/13] securable guest memory: Alter virtio default properties for protected guests
Date: Thu, 17 Dec 2020 16:53:38 +1100 [thread overview]
Message-ID: <20201217055338.GI310465@yekko.fritz.box> (raw)
In-Reply-To: <20201208135005.100d56fb.cohuck@redhat.com>
[-- Attachment #1: Type: text/plain, Size: 2449 bytes --]
On Tue, Dec 08, 2020 at 01:50:05PM +0100, Cornelia Huck wrote:
> On Tue, 8 Dec 2020 11:28:29 +0100
> Halil Pasic <pasic@linux.ibm.com> wrote:
>
> > On Tue, 8 Dec 2020 12:54:03 +1100
> > David Gibson <david@gibson.dropbear.id.au> wrote:
> >
> > > > > >>> + * Virtio devices can't count on directly accessing guest
> > > > > >>> + * memory, so they need iommu_platform=on to use normal DMA
> > > > > >>> + * mechanisms. That requires also disabling legacy virtio
> > > > > >>> + * support for those virtio pci devices which allow it.
> > > > > >>> + */
> > > > > >>> + object_register_sugar_prop(TYPE_VIRTIO_PCI, "disable-legacy",
> > > > > >>> + "on", true);
> > > > > >>> + object_register_sugar_prop(TYPE_VIRTIO_DEVICE, "iommu_platform",
> > > > > >>> + "on", false);
> > > > > >>
> > > > > >> I have not followed all the history (sorry). Should we also set iommu_platform
> > > > > >> for virtio-ccw? Halil?
> > > > > >>
> > > > > >
> > > > > > That line should add iommu_platform for all virtio devices, shouldn't
> > > > > > it?
> > > > >
> > > > > Yes, sorry. Was misreading that with the line above.
> > > > >
> > > >
> > > > I believe this is the best we can get. In a sense it is still a
> > > > pessimization,
> > >
> > > I'm not really clear on what you're getting at here.
> >
> > By pessimiziation, I mean that we are going to indicate
> > _F_PLATFORM_ACCESS even if it isn't necessary, because the guest never
> > opted in for confidential/memory protection/memory encryption. We have
> > discussed this before, and I don't see a better solution that works for
> > everybody.
>
> If you consider specifying the secure guest option as a way to tell
> QEMU to make everything ready for running a secure guest, I'd certainly
> consider it necessary. If you do not want to force it, you should not
> do the secure guest preparation setup.
Right, that's my feeling as well.
I'm also of the opinion that !F_PLATFORM_ACCESS is kind of a nasty
hack that has some other problems (e.g. it means an L1 can't safely
pass the device into an L2).
--
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
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next prev parent reply other threads:[~2020-12-17 6:01 UTC|newest]
Thread overview: 186+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-04 5:44 [for-6.0 v5 00/13] Generalize memory encryption models David Gibson
2020-12-04 5:44 ` David Gibson
2020-12-04 5:44 ` [for-6.0 v5 01/13] qom: Allow optional sugar props David Gibson
2020-12-04 5:44 ` David Gibson
2020-12-04 12:57 ` Cornelia Huck
2020-12-04 12:57 ` Cornelia Huck
2020-12-14 21:25 ` Eduardo Habkost
2020-12-14 21:25 ` Eduardo Habkost
2021-01-11 18:04 ` Philippe Mathieu-Daudé
2021-01-11 18:04 ` Philippe Mathieu-Daudé
2020-12-04 5:44 ` [for-6.0 v5 02/13] securable guest memory: Introduce new securable guest memory base class David Gibson
2020-12-04 5:44 ` David Gibson
2020-12-04 5:44 ` [for-6.0 v5 03/13] securable guest memory: Handle memory encryption via interface David Gibson
2020-12-04 5:44 ` David Gibson
2020-12-04 13:10 ` Cornelia Huck
2020-12-04 13:10 ` Cornelia Huck
2021-01-08 4:03 ` David Gibson
2021-01-08 4:03 ` David Gibson
2021-01-12 3:49 ` David Gibson
2021-01-12 3:49 ` David Gibson
2020-12-04 5:44 ` [for-6.0 v5 04/13] securable guest memory: Move side effect out of machine_set_memory_encryption() David Gibson
2020-12-04 5:44 ` David Gibson
2020-12-04 5:44 ` [for-6.0 v5 05/13] securable guest memory: Rework the "memory-encryption" property David Gibson
2020-12-04 5:44 ` David Gibson
2021-01-11 18:09 ` Philippe Mathieu-Daudé
2021-01-11 18:09 ` Philippe Mathieu-Daudé
2020-12-04 5:44 ` [for-6.0 v5 06/13] securable guest memory: Decouple kvm_memcrypt_*() helpers from KVM David Gibson
2020-12-04 5:44 ` David Gibson
2021-01-11 18:13 ` Philippe Mathieu-Daudé
2021-01-11 18:13 ` Philippe Mathieu-Daudé
2021-01-12 3:03 ` David Gibson
2021-01-12 3:03 ` David Gibson
2020-12-04 5:44 ` [for-6.0 v5 07/13] sev: Add Error ** to sev_kvm_init() David Gibson
2020-12-04 5:44 ` David Gibson
2020-12-14 16:50 ` Cornelia Huck
2020-12-14 16:50 ` Cornelia Huck
2020-12-04 5:44 ` [for-6.0 v5 08/13] securable guest memory: Introduce sgm "ready" flag David Gibson
2020-12-04 5:44 ` David Gibson
2020-12-14 17:00 ` Cornelia Huck
2020-12-14 17:00 ` Cornelia Huck
2020-12-17 5:38 ` David Gibson
2020-12-17 5:38 ` David Gibson
2020-12-17 11:24 ` Cornelia Huck
2020-12-17 11:24 ` Cornelia Huck
2020-12-04 5:44 ` [for-6.0 v5 09/13] securable guest memory: Move SEV initialization into arch specific code David Gibson
2020-12-04 5:44 ` David Gibson
2020-12-04 5:44 ` [for-6.0 v5 10/13] spapr: Add PEF based securable guest memory David Gibson
2020-12-04 5:44 ` David Gibson
2021-01-05 23:34 ` Ram Pai
2021-01-05 23:34 ` Ram Pai
2021-01-08 0:34 ` David Gibson
2021-01-08 0:34 ` David Gibson
2020-12-04 5:44 ` [for-6.0 v5 11/13] spapr: PEF: prevent migration David Gibson
2020-12-04 5:44 ` David Gibson
2020-12-14 17:22 ` Cornelia Huck
2020-12-14 17:22 ` Cornelia Huck
2020-12-17 5:47 ` David Gibson
2020-12-17 5:47 ` David Gibson
2020-12-17 11:38 ` Cornelia Huck
2020-12-17 11:38 ` Cornelia Huck
2020-12-17 14:15 ` Greg Kurz
2020-12-17 14:15 ` Greg Kurz
2020-12-18 11:41 ` Cornelia Huck
2020-12-18 11:41 ` Cornelia Huck
2020-12-18 12:08 ` Dr. David Alan Gilbert
2020-12-18 12:08 ` Dr. David Alan Gilbert
2021-01-04 7:15 ` Ram Pai
2021-01-04 7:15 ` Ram Pai
2021-01-04 12:46 ` [EXTERNAL] " Halil Pasic
2021-01-04 12:46 ` Halil Pasic
2021-01-04 18:40 ` Ram Pai
2021-01-04 18:40 ` Ram Pai
2021-01-05 10:56 ` [EXTERNAL] " Halil Pasic
2021-01-05 10:56 ` Halil Pasic
2021-01-05 20:41 ` Ram Pai
2021-01-05 20:41 ` Ram Pai
2021-01-11 16:59 ` Cornelia Huck
2021-01-11 16:59 ` Cornelia Huck
2021-01-11 19:58 ` Ram Pai
2021-01-11 19:58 ` Ram Pai
2021-01-12 8:19 ` Cornelia Huck
2021-01-12 8:19 ` Cornelia Huck
2021-01-12 18:55 ` Ram Pai
2021-01-12 18:55 ` Ram Pai
2021-01-13 8:06 ` Cornelia Huck
2021-01-13 8:06 ` Cornelia Huck
2021-01-15 18:55 ` Ram Pai
2021-01-15 18:55 ` Ram Pai
2021-01-19 8:19 ` Cornelia Huck
2021-01-19 8:19 ` Cornelia Huck
2021-01-19 9:59 ` Daniel P. Berrangé
2021-01-19 9:59 ` Daniel P. Berrangé
2021-01-14 11:23 ` Daniel P. Berrangé
2021-01-14 11:23 ` Daniel P. Berrangé
2021-01-13 12:42 ` Dr. David Alan Gilbert
2021-01-13 12:42 ` Dr. David Alan Gilbert
2021-01-14 10:28 ` Christian Borntraeger
2021-01-14 10:28 ` Christian Borntraeger
2021-01-14 10:36 ` Dr. David Alan Gilbert
2021-01-14 10:36 ` Dr. David Alan Gilbert
2021-01-14 10:52 ` Christian Borntraeger
2021-01-14 10:52 ` Christian Borntraeger
2021-01-14 11:05 ` Cornelia Huck
2021-01-14 11:05 ` Cornelia Huck
2021-01-14 11:45 ` Dr. David Alan Gilbert
2021-01-14 11:45 ` Dr. David Alan Gilbert
2021-01-14 11:50 ` Christian Borntraeger
2021-01-14 11:50 ` Christian Borntraeger
2021-01-14 12:20 ` Daniel P. Berrangé
2021-01-14 12:20 ` Daniel P. Berrangé
2021-01-14 14:04 ` Cornelia Huck
2021-01-14 14:04 ` Cornelia Huck
2021-01-14 14:09 ` Christian Borntraeger
2021-01-14 14:09 ` Christian Borntraeger
2021-01-14 14:15 ` Daniel P. Berrangé
2021-01-14 14:15 ` Daniel P. Berrangé
2021-01-14 15:25 ` Christian Borntraeger
2021-01-14 15:25 ` Christian Borntraeger
2021-01-14 15:33 ` Daniel P. Berrangé
2021-01-14 15:33 ` Daniel P. Berrangé
2021-01-15 18:24 ` Ram Pai
2021-01-15 18:24 ` Ram Pai
2021-01-14 11:25 ` Daniel P. Berrangé
2021-01-14 11:25 ` Daniel P. Berrangé
2021-01-14 23:51 ` David Gibson
2021-01-14 23:51 ` David Gibson
2021-01-18 17:39 ` Dr. David Alan Gilbert
2021-01-18 17:39 ` Dr. David Alan Gilbert
2021-01-19 8:28 ` Christian Borntraeger
2021-01-19 8:28 ` Christian Borntraeger
2021-01-19 8:34 ` Cornelia Huck
2021-01-19 8:34 ` Cornelia Huck
2020-12-04 5:44 ` [for-6.0 v5 12/13] securable guest memory: Alter virtio default properties for protected guests David Gibson
2020-12-04 5:44 ` David Gibson
2020-12-04 8:10 ` Christian Borntraeger
2020-12-04 8:10 ` Christian Borntraeger
2020-12-04 8:17 ` Cornelia Huck
2020-12-04 8:17 ` Cornelia Huck
2020-12-04 8:29 ` Christian Borntraeger
2020-12-04 8:29 ` Christian Borntraeger
2020-12-04 14:43 ` Halil Pasic
2020-12-04 14:43 ` Halil Pasic
2020-12-08 1:54 ` David Gibson
2020-12-08 1:54 ` David Gibson
2020-12-08 8:16 ` Christian Borntraeger
2020-12-08 8:16 ` Christian Borntraeger
2020-12-08 10:28 ` Halil Pasic
2020-12-08 10:28 ` Halil Pasic
2020-12-08 12:50 ` Cornelia Huck
2020-12-08 12:50 ` Cornelia Huck
2020-12-17 5:53 ` David Gibson [this message]
2020-12-17 5:53 ` David Gibson
2020-12-04 17:04 ` Cornelia Huck
2020-12-04 17:04 ` Cornelia Huck
2020-12-04 5:44 ` [for-6.0 v5 13/13] s390: Recognize securable-guest-memory option David Gibson
2020-12-04 5:44 ` David Gibson
2020-12-15 11:45 ` Cornelia Huck
2020-12-15 11:45 ` Cornelia Huck
2020-12-17 5:54 ` David Gibson
2020-12-17 5:54 ` David Gibson
2020-12-04 8:06 ` [for-6.0 v5 00/13] Generalize memory encryption models Christian Borntraeger
2020-12-04 8:06 ` Christian Borntraeger
2020-12-04 13:02 ` Cornelia Huck
2020-12-04 13:02 ` Cornelia Huck
2020-12-04 13:07 ` Dr. David Alan Gilbert
2020-12-04 13:07 ` Dr. David Alan Gilbert
2020-12-04 13:12 ` Cornelia Huck
2020-12-04 13:12 ` Cornelia Huck
2020-12-08 2:57 ` David Gibson
2020-12-08 2:57 ` David Gibson
2020-12-08 12:43 ` Cornelia Huck
2020-12-08 12:43 ` Cornelia Huck
2020-12-17 6:21 ` David Gibson
2020-12-17 6:21 ` David Gibson
2020-12-17 11:43 ` Cornelia Huck
2020-12-17 11:43 ` Cornelia Huck
2020-12-04 13:25 ` Daniel P. Berrangé
2020-12-04 13:25 ` Daniel P. Berrangé
2020-12-04 13:51 ` Halil Pasic
2020-12-04 13:51 ` Halil Pasic
2020-12-08 2:54 ` David Gibson
2020-12-08 2:54 ` David Gibson
2020-12-04 9:50 ` Daniel P. Berrangé
2020-12-04 9:50 ` Daniel P. Berrangé
2021-01-12 3:02 ` David Gibson
2021-01-12 3:02 ` David Gibson
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