Re: [virtio-dev] [PATCH] split-ring: Demand that a device must not change descriptor entries

[Rob Miller <rob.miller@broadcom.com>]

what is trying to be solvedÂhere? There is a reason why this is allowed as some vendors update the table when using RX_MERABLE_BUFFERs & F_IN_ORDER features

Rob Miller

rob.miller@broadcom.com

(919)721-3339

On Mon, Nov 11, 2019 at 12:13 PM Jan Kiszka <jan.kiszka@siemens.com> wrote:

From: Jan Kiszka <jan.kiszka@siemens.com>

So far the spec only indirectly says that a descriptor table entry is
not modified by a device when processing it. Make this explicit by
adding it as normative requirement. Existing drivers already depend on
this.

See also https://lists.oasis-open.org/archives/virtio-dev/201910/msg00057.html.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
Âsplit-ring.tex | 2 +-
Â1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/split-ring.tex b/split-ring.tex
index 123ac9f..bfef62d 100644
--- a/split-ring.tex
+++ b/split-ring.tex
@@ -217,7 +217,7 @@ \subsection{The Virtqueue Descriptor Table}\label{sec:Basic Facilities of a Virt
Â\devicenormative{\subsubsection}{The Virtqueue Descriptor Table}{Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table}
ÂA device MUST NOT write to a device-readable buffer, and a device SHOULD NOT
Âread a device-writable buffer (it MAY do so for debugging or diagnostic
-purposes).
+purposes). A device MUST NOT write to any descriptor table entry.

Â\drivernormative{\subsubsection}{The Virtqueue Descriptor Table}{Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table}
ÂDrivers MUST NOT add a descriptor chain longer than $2^{32}$ bytes in total;
--
2.16.4

---------------------------------------------------------------------
To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org
For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org