From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 61ABC4617B; Mon, 3 Feb 2025 05:01:01 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id E7D984060F; Mon, 3 Feb 2025 05:01:00 +0100 (CET) Received: from inbox.dpdk.org (inbox.dpdk.org [95.142.172.178]) by mails.dpdk.org (Postfix) with ESMTP id 33CF3400EF for ; Mon, 3 Feb 2025 05:01:00 +0100 (CET) Received: by inbox.dpdk.org (Postfix, from userid 33) id 13EA14617C; Mon, 3 Feb 2025 05:01:00 +0100 (CET) From: bugzilla@dpdk.org To: dev@dpdk.org Subject: [DPDK/vhost/virtio Bug 1648] virtio tx_burst() function cannot do TSO on shared packets Date: Mon, 03 Feb 2025 04:01:00 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: DPDK X-Bugzilla-Component: vhost/virtio X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: nandinipersad361@gmail.com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: Normal X-Bugzilla-Assigned-To: dev@dpdk.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter target_milestone Message-ID: Content-Type: multipart/alternative; boundary=17385552590.B5abEB0Bf.2151910 Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://bugs.dpdk.org/ Auto-Submitted: auto-generated X-Auto-Response-Suppress: All MIME-Version: 1.0 X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org --17385552590.B5abEB0Bf.2151910 Date: Mon, 3 Feb 2025 05:00:59 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://bugs.dpdk.org/ Auto-Submitted: auto-generated X-Auto-Response-Suppress: All https://bugs.dpdk.org/show_bug.cgi?id=3D1648 Bug ID: 1648 Summary: virtio tx_burst() function cannot do TSO on shared packets Product: DPDK Version: unspecified Hardware: All OS: All Status: UNCONFIRMED Severity: normal Priority: Normal Component: vhost/virtio Assignee: dev@dpdk.org Reporter: nandinipersad361@gmail.com Target Milestone: --- The standard TX function of virtio driver does not manage shared packets properly when doing TSO. These packets should be read-only but the driver modifies them. When doing TSO, the virtio standard expects that the L4 checksum is set to = the pseudo header checksum in the packet data, which is different than the DPDK API. The driver patches the L4 checksum to conform to the virtio standard, = but this solution is invalid when dealing with shared packets (clones), because= the packet data should not be modified. Implication: In this situation, the shared data will be modified by the driver, potentia= lly causing race conditions with the other users of the mbuf data. Resolution/Workaround: The workaround in the application is to ensure that the network headers in = the packet data are not shared. Affected Environment/Platform: Virtual machines running a virtio driver. Driver/Module: Poll Mode Driver (PMD). --=20 You are receiving this mail because: You are the assignee for the bug.= --17385552590.B5abEB0Bf.2151910 Date: Mon, 3 Feb 2025 05:00:59 +0100 MIME-Version: 1.0 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://bugs.dpdk.org/ Auto-Submitted: auto-generated X-Auto-Response-Suppress: All
Bug ID 1648
Summary virtio tx_burst() function cannot do TSO on shared packets
Product DPDK
Version unspecified
Hardware All
OS All
Status UNCONFIRMED
Severity normal
Priority Normal
Component vhost/virtio
Assignee dev@dpdk.org
Reporter nandinipersad361@gmail.com
Target Milestone --- 

The standard TX function of virtio=
 driver does not manage shared packets
properly when doing TSO. These packets should be read-only but the driver
modifies them.

When doing TSO, the virtio standard expects that the L4 checksum is set to =
the
pseudo header checksum in the packet data, which is different than the DPDK
API. The driver patches the L4 checksum to conform to the virtio standard, =
but
this solution is invalid when dealing with shared packets (clones), because=
 the
packet data should not be modified.

Implication:
In this situation, the shared data will be modified by the driver, potentia=
lly
causing race conditions with the other users of the mbuf data.

Resolution/Workaround:
The workaround in the application is to ensure that the network headers in =
the
packet data are not shared.

Affected Environment/Platform:
Virtual machines running a virtio driver.

Driver/Module:
Poll Mode Driver (PMD).

You are receiving this mail because:
  • You are the assignee for the bug.
=20=20=20=20=20=20=20=20=20=20
= --17385552590.B5abEB0Bf.2151910--