linux-kernel - Re: virtio-pci new configuration proposal

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:	Wed, 2 Nov 2011 21:08:06 +0200
From:	"Michael S. Tsirkin" <mst@...hat.com>
To:	Sasha Levin <levinsasha928@...il.com>
Cc:	Rusty Russell <rusty@...tcorp.com.au>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	kvm <kvm@...r.kernel.org>,
	virtualization <virtualization@...ts.linux-foundation.org>
Subject: Re: virtio-pci new configuration proposal

On Wed, Nov 02, 2011 at 08:49:27PM +0200, Sasha Levin wrote:
> This is a proposal for a new layout of the virtio-pci config space.
> 
> We will separate the current configuration into two: A virtio-pci common
> configuration and a device specific configuration. This allows more flexibility
> with adding features and makes usage easier, specifically in cases like the
> ones in virtio-net where device specific configurations depend on device
> specific features.
> 
> The preferred location of the configuration will be a MMIO BAR, therefore
> several size optimizations such as the queue selector which were useful
> on a PIO BAR were removed and linked lists were introduced to add
> flexibility to existing structures in attempt to keep their size and
> offsets constant and not dependent on features.
> 
> While this is not a complete specification, it describes all the main
> structures and should be enough to make sure the idea is solid before
> going into implementation specifics.
> 
> A new virtio-pci capability structure will be introduced. This structure
> will be used to describe the basics of a virtio-pci device. The
> structure is actually a PCI capability structure which wraps the new virtio-pci
> capability structure:
> 
> +------------++------------+------------+------------+--------------+-----------------
> | Bits       || 8          | 8          | 8          | 8            | Cap specific
> +------------++------------+------------+------------+--------------+-----------------
> | Read/Write || R          | R          | R          | R            | Cap specific
> +------------++------------+------------+------------+--------------+-----------------
> | Purpose    || Capability | Capability | virtio-pci | virtio-pci   | Cap specific
> |            || ID         | Next PTR   | Cap ID     | Next Cap PTR |
> +------------++------------+------------+------------+--------------+-----------------
> 
> Currently, only one virtio-pci capability is defined, and is the one that defines
> the layout of the virtio-pci config space.
> 
> VIRTIO_PCI_C_LAYOUT:
> 
> +------------++---------------+---------------+-----------------+-----------------+
> | Bits       || 29            | 3             | 29              | 3               |
> +------------++---------------+---------------+-----------------+-----------------+
> | Read/Write || R             | R             | R               | R               |
> +------------++---------------+---------------+-----------------+-----------------+
> | Purpose    || Common config | Common config | Device specific | Device specific |
> |            || Offset        | BIR           | Offset          | BIR             |
> +------------++---------------+---------------+-----------------+-----------------+

I'm implementing a different layout, with
separate capabilities for common and device specific
fields.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/