linux-kernel - Question about reserved

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-next>] [day] [month] [year] [list]

Message-ID: <CAKgT0UezciLjHacOx372+v8MZkDf22D5Thn82n-07xxKy_0FTQ@mail.gmail.com>
Date:   Wed, 7 Jun 2023 15:40:26 -0700
From:   Alexander Duyck <alexander.duyck@...il.com>
To:     LKML <linux-kernel@...r.kernel.org>,
        "open list:INTEL IOMMU (VT-d)" <iommu@...ts.linux-foundation.org>,
        linux-pci <linux-pci@...r.kernel.org>
Subject: Question about reserved_regions w/ Intel IOMMU

I am running into a DMA issue that appears to be a conflict between
ACS and IOMMU. As per the documentation I can find, the IOMMU is
supposed to create reserved regions for MSI and the memory window
behind the root port. However looking at reserved_regions I am not
seeing that. I only see the reservation for the MSI.

So for example with an enabled NIC and iommu enabled w/o passthru I am seeing:
# cat /sys/bus/pci/devices/0000\:83\:00.0/iommu_group/reserved_regions
0x00000000fee00000 0x00000000feefffff msi

Shouldn't there also be a memory window for the region behind the root
port to prevent any possible peer-to-peer access?