From: Thiago Jung Bauermann <bauerman@linux.ibm.com>
To: virtualization@lists.linux-foundation.org
Cc: linuxppc-dev@lists.ozlabs.org, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org,
"Michael S . Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>, Christoph Hellwig <hch@lst.de>,
David Gibson <david@gibson.dropbear.id.au>,
Alexey Kardashevskiy <aik@linux.ibm.com>,
Paul Mackerras <paulus@ozlabs.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Ram Pai <linuxram@us.ibm.com>
Subject: Re: [RFC PATCH] virtio_ring: Use DMA API if guest memory is encrypted
Date: Tue, 29 Jan 2019 15:42:44 -0200 [thread overview]
Message-ID: <87womn8inf.fsf@morokweng.localdomain> (raw)
In-Reply-To: <87zhrj8kcp.fsf@morokweng.localdomain>
Fixing address of powerpc mailing list.
Thiago Jung Bauermann <bauerman@linux.ibm.com> writes:
> Hello,
>
> With Christoph's rework of the DMA API that recently landed, the patch
> below is the only change needed in virtio to make it work in a POWER
> secure guest under the ultravisor.
>
> The other change we need (making sure the device's dma_map_ops is NULL
> so that the dma-direct/swiotlb code is used) can be made in
> powerpc-specific code.
>
> Of course, I also have patches (soon to be posted as RFC) which hook up
> <linux/mem_encrypt.h> to the powerpc secure guest support code.
>
> What do you think?
>
> From d0629a36a75c678b4a72b853f8f7f8c17eedd6b3 Mon Sep 17 00:00:00 2001
> From: Thiago Jung Bauermann <bauerman@linux.ibm.com>
> Date: Thu, 24 Jan 2019 22:08:02 -0200
> Subject: [RFC PATCH] virtio_ring: Use DMA API if guest memory is encrypted
>
> The host can't access the guest memory when it's encrypted, so using
> regular memory pages for the ring isn't an option. Go through the DMA API.
>
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
> ---
> drivers/virtio/virtio_ring.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index cd7e755484e3..321a27075380 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -259,8 +259,11 @@ static bool vring_use_dma_api(struct virtio_device *vdev)
> * not work without an even larger kludge. Instead, enable
> * the DMA API if we're a Xen guest, which at least allows
> * all of the sensible Xen configurations to work correctly.
> + *
> + * Also, if guest memory is encrypted the host can't access
> + * it directly. In this case, we'll need to use the DMA API.
> */
> - if (xen_domain())
> + if (xen_domain() || sev_active())
> return true;
>
> return false;
--
Thiago Jung Bauermann
IBM Linux Technology Center
next prev parent reply other threads:[~2019-01-29 17:42 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-29 17:08 [RFC PATCH] virtio_ring: Use DMA API if guest memory is encrypted Thiago Jung Bauermann
2019-01-29 17:42 ` Thiago Jung Bauermann [this message]
2019-01-29 19:02 ` Michael S. Tsirkin
2019-01-30 2:24 ` Jason Wang
2019-01-30 2:36 ` Michael S. Tsirkin
2019-01-30 3:05 ` Jason Wang
2019-01-30 3:26 ` Michael S. Tsirkin
2019-01-30 7:44 ` Christoph Hellwig
2019-02-04 18:15 ` Thiago Jung Bauermann
2019-02-04 21:38 ` Michael S. Tsirkin
2019-02-05 7:24 ` Christoph Hellwig
[not found] ` <20190205072407.GA4311-jcswGhMUV9g@public.gmane.org>
2019-02-05 16:13 ` Michael S. Tsirkin
2019-03-26 16:53 ` Michael S. Tsirkin
2019-02-04 18:14 ` Thiago Jung Bauermann
2019-02-04 20:23 ` Michael S. Tsirkin
2019-03-20 16:13 ` Thiago Jung Bauermann
2019-03-20 21:17 ` Michael S. Tsirkin
2019-03-22 0:05 ` Thiago Jung Bauermann
2019-03-23 21:01 ` Michael S. Tsirkin
2019-03-25 0:57 ` David Gibson
2019-04-17 21:42 ` Thiago Jung Bauermann
2019-04-17 21:42 ` Thiago Jung Bauermann
[not found] ` <20190323165456-mutt-send-email-mst-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2019-04-17 21:42 ` Thiago Jung Bauermann
2019-04-17 21:42 ` Thiago Jung Bauermann
2019-04-19 23:09 ` Michael S. Tsirkin
2019-04-19 23:09 ` Michael S. Tsirkin
2019-04-25 1:01 ` Thiago Jung Bauermann
2019-04-25 1:01 ` Thiago Jung Bauermann
[not found] ` <875zr228zf.fsf-wxVGo8vDogbJvNEK5ZsId7p2dZbC/Bob@public.gmane.org>
2019-04-25 1:18 ` Michael S. Tsirkin
2019-04-25 1:18 ` Michael S. Tsirkin
2019-04-26 23:56 ` Thiago Jung Bauermann
2019-04-26 23:56 ` Thiago Jung Bauermann
2019-05-20 13:08 ` Michael S. Tsirkin
2019-05-20 13:16 ` Michael S. Tsirkin
2019-06-04 1:13 ` Thiago Jung Bauermann
2019-06-04 1:42 ` Michael S. Tsirkin
2019-06-28 1:58 ` Thiago Jung Bauermann
2019-07-01 14:17 ` Michael S. Tsirkin
2019-07-14 5:51 ` Thiago Jung Bauermann
2019-07-15 14:35 ` Michael S. Tsirkin
2019-07-15 20:29 ` Thiago Jung Bauermann
2019-07-15 20:36 ` Michael S. Tsirkin
2019-07-15 22:03 ` Thiago Jung Bauermann
2019-07-15 22:16 ` Michael S. Tsirkin
2019-07-15 23:05 ` Thiago Jung Bauermann
2019-07-15 23:24 ` Benjamin Herrenschmidt
2019-07-18 3:39 ` Thiago Jung Bauermann
2019-08-10 18:57 ` Michael S. Tsirkin
2019-08-10 22:07 ` Ram Pai
2019-08-11 5:56 ` Christoph Hellwig
2019-08-11 6:46 ` Ram Pai
2019-08-11 8:44 ` Michael S. Tsirkin
2019-08-12 12:13 ` Christoph Hellwig
2019-08-12 20:29 ` Ram Pai
2019-08-11 8:42 ` Michael S. Tsirkin
2019-08-11 8:55 ` Michael S. Tsirkin
2019-08-12 12:15 ` Christoph Hellwig
2019-09-06 5:07 ` Michael S. Tsirkin
2019-08-12 9:51 ` David Gibson
2019-08-13 13:26 ` Christoph Hellwig
2019-08-13 14:24 ` David Gibson
2019-08-13 15:45 ` Ram Pai
2019-08-26 17:48 ` Ram Pai
2019-08-11 8:12 ` Michael S. Tsirkin
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