linux-kernel - Re: [PATCH v6 0/9] virtio DMA API, yet again

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 2 Feb 2016 10:54:02 +0100
From:	Christian Borntraeger <borntraeger@...ibm.com>
To:	Andy Lutomirski <luto@...nel.org>,
	"Michael S. Tsirkin" <mst@...hat.com>
Cc:	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	David Woodhouse <dwmw2@...radead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"David S. Miller" <davem@...emloft.net>,
	sparclinux@...r.kernel.org, Joerg Roedel <jroedel@...e.de>,
	Cornelia Huck <cornelia.huck@...ibm.com>,
	Sebastian Ott <sebott@...ux.vnet.ibm.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Christoph Hellwig <hch@....de>, KVM <kvm@...r.kernel.org>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	linux-s390 <linux-s390@...r.kernel.org>,
	Linux Virtualization <virtualization@...ts.linux-foundation.org>,
	David Vrabel <david.vrabel@...rix.com>,
	Stefano Stabellini <stefano.stabellini@...citrix.com>,
	xen-devel@...ts.xenproject.org,
	Cornelia Huck <cornelia.huck@...ibm.com>
Subject: Re: [PATCH v6 0/9] virtio DMA API, yet again

On 02/01/2016 07:00 PM, Andy Lutomirski wrote:
> This switches virtio to use the DMA API on Xen and if requested by
> module option.
> 
> This fixes virtio on Xen, and it should break anything because it's
> off by default on everything except Xen PV on x86.
> 
> To the Xen people: is this okay?  If it doesn't work on other Xen
> variants (PVH? HVM?), can you submit follow-up patches to fix it?
> 
> To everyone else: we've waffled on this for way too long.  I think
> we should to get DMA API implementation in with a conservative
> policy like this rather than waiting until we achieve perfection.
> I'm tired of carrying these patches around.

I used your branch pub/scm/linux/kernel/git/luto/linux.git virtio_dma
on kernel.org.

It seems to survive a basic test (simple block and net) on s390 with
and without dma api enabled. No full test, though.

> 
> Michael, if these survive review, can you stage these in your tree?
> Can you also take a look at tools/virtio?  I probably broke it, but I
> couldn't get it to build without these patches either, so I'm stuck.
> 
> Changes from v5:
>  - Typo fixes (David Woodhouse)
>  - Use xen_domain() to detect Xen (David Vrabel)
>  - Pass struct vring_virtqueue * into vring_use_dma_api for future proofing
>  - Removed module parameter (Michael)
> 
> Changes from v4:
>  - Bake vring_use_dma_api in from the beginning.
>  - Automatically enable only on Xen.
>  - Add module parameter.
>  - Add s390 and alpha DMA API implementations.
>  - Rebase to 4.5-rc1.
> 
> Changes from v3:
>  - More big-endian fixes.
>  - Added better virtio-ring APIs that handle allocation and use them in
>    virtio-mmio and virtio-pci.
>  - Switch to Michael's virtio-net patch.
> 
> Changes from v2:
>  - Fix vring_mapping_error incorrect argument
> 
> Changes from v1:
>  - Fix an endian conversion error causing a BUG to hit.
>  - Fix a DMA ordering issue (swiotlb=force works now).
>  - Minor cleanups.
> 
> Andy Lutomirski (6):
>   vring: Introduce vring_use_dma_api()
>   virtio_ring: Support DMA APIs
>   virtio: Add improved queue allocation API
>   virtio_mmio: Use the DMA API if enabled
>   virtio_pci: Use the DMA API if enabled
>   vring: Use the DMA API on Xen
> 
> Christian Borntraeger (3):
>   dma: Provide simple noop dma ops
>   alpha/dma: use common noop dma ops
>   s390/dma: Allow per device dma ops
> 
>  arch/alpha/kernel/pci-noop.c        |  46 +---
>  arch/s390/Kconfig                   |   6 +-
>  arch/s390/include/asm/device.h      |   6 +-
>  arch/s390/include/asm/dma-mapping.h |   6 +-
>  arch/s390/pci/pci.c                 |   1 +
>  arch/s390/pci/pci_dma.c             |   4 +-
>  drivers/virtio/Kconfig              |   2 +-
>  drivers/virtio/virtio_mmio.c        |  67 ++----
>  drivers/virtio/virtio_pci_common.h  |   6 -
>  drivers/virtio/virtio_pci_legacy.c  |  42 ++--
>  drivers/virtio/virtio_pci_modern.c  |  61 ++----
>  drivers/virtio/virtio_ring.c        | 408 ++++++++++++++++++++++++++++++------
>  include/linux/dma-mapping.h         |   2 +
>  include/linux/virtio.h              |  23 +-
>  include/linux/virtio_ring.h         |  35 ++++
>  lib/Makefile                        |   1 +
>  lib/dma-noop.c                      |  75 +++++++
>  tools/virtio/linux/dma-mapping.h    |  17 ++
>  18 files changed, 564 insertions(+), 244 deletions(-)
>  create mode 100644 lib/dma-noop.c
>  create mode 100644 tools/virtio/linux/dma-mapping.h
>