linux-kernel - RE: [PATCH] iommu/vt-d: Handle hotplug devices' default identity mapping setting

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]

Message-Id: <20190222082829.75567-1-xmdong@google.com>
Date:   Fri, 22 Feb 2019 08:28:29 +0000
From:   James Dong <xmdong@...gle.com>
To:     Lu Baolu <baolu.lu@...ux.intel.com>
Cc:     David Woodhouse <dwmw2@...radead.org>,
        Joerg Roedel <joro@...tes.org>,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Jis Ben <jisben@...gle.com>, James Dong <xmdong@...gle.com>
Subject: RE: [PATCH] iommu/vt-d: Handle hotplug devices' default identity
 mapping setting

Baolu:

The reproduction depends on devices. HW passthrough PCIe devices with default
identity map could have the issue. Make sure that messages like following came
out in dmesg and their mapping does not change after booting:
  [   10.167809] DMAR: Hardware identity mapping for device 0000:30:00.0
  [   10.167823] DMAR: Hardware identity mapping for device 0000:30:00.1

Devices which make following true could also be used for the experiment:
  > static int iommu_should_identity_map(struct device *dev, int startup)
  > {
  >		if ((iommu_identity_mapping & IDENTMAP_AZALIA) && IS_AZALIA(pdev))
  >			return 1;
  >		if ((iommu_identity_mapping & IDENTMAP_GFX) && IS_GFX_DEVICE(pdev))
  >			return 1;

Once they are up, remove them first by following command:
  echo 1 > /sys/bus/pci/devices/0000\:03\:00.1/remove

Then trigger the hotplug device rescanning:
  echo 1 > /sys/bus/pci/rescan

To provide an example of specific devices on the market, I need to try out.
Or, if it is fine with you, forcing a PCIe NIC card to be default hardware
passthrough by changing the intel-iommu.c is another easy way to reproduce
this issue.

Best Regards,
James