LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Alex Williamson <alex.williamson@redhat.com>
To: linux-pci@vger.kernel.org, bhelgaas@google.com
Cc: rajatja@google.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PCI/ACS: Enforce pci=noats with Transaction Blocking
Date: Tue, 3 Aug 2021 12:49:31 -0600	[thread overview]
Message-ID: <20210803124931.270ca006.alex.williamson@redhat.com> (raw)
In-Reply-To: <162404966325.2362347.12176138291577486015.stgit@omen>


Bump.

On Fri, 18 Jun 2021 14:55:14 -0600
Alex Williamson <alex.williamson@redhat.com> wrote:

> PCIe Address Translation Services (ATS) provides a mechanism for a
> device to provide an on-device caching translation agent (device
> iotlb).  We already have a means to disable support for this feature
> via the pci=noats option.  For untrusted and externally facing
> devices, we not only disable ATS support for the device, but we use
> Access Control Services (ACS) Transaction Blocking to actively
> prevent devices from sending TLPs with non-default AT field values.
> 
> Extend pci=noats to also make use of PCI_ACS_TB so that not only is
> ATS disabled at the device, but blocked at the downstream ports.
> This provides a means to further lock-down ATS for cases such as
> device assignment, where it may not be the hardware configuration of
> the device that makes it untrusted, but the driver running on the
> device.
> 
> Cc: Rajat Jain <rajatja@google.com>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> ---
>  drivers/pci/pci.c    |    4 ++--
>  drivers/pci/quirks.c |    2 +-
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 68f57d86b243..5aa1bb2ddd80 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -915,8 +915,8 @@ static void pci_std_enable_acs(struct pci_dev *dev)
>  	/* Upstream Forwarding */
>  	ctrl |= (cap & PCI_ACS_UF);
>  
> -	/* Enable Translation Blocking for external devices */
> -	if (dev->external_facing || dev->untrusted)
> +	/* Enable Translation Blocking for external devices and noats */
> +	if (pci_ats_disabled() || dev->external_facing || dev->untrusted)
>  		ctrl |= (cap & PCI_ACS_TB);
>  
>  	pci_write_config_word(dev, pos + PCI_ACS_CTRL, ctrl);
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 6d74386eadc2..d541076c083a 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -5031,7 +5031,7 @@ static int pci_quirk_enable_intel_spt_pch_acs(struct pci_dev *dev)
>  	ctrl |= (cap & PCI_ACS_CR);
>  	ctrl |= (cap & PCI_ACS_UF);
>  
> -	if (dev->external_facing || dev->untrusted)
> +	if (pci_ats_disabled() || dev->external_facing || dev->untrusted)
>  		ctrl |= (cap & PCI_ACS_TB);
>  
>  	pci_write_config_dword(dev, pos + INTEL_SPT_ACS_CTRL, ctrl);
> 
> 


  reply	other threads:[~2021-08-03 18:49 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-18 20:55 Alex Williamson
2021-08-03 18:49 ` Alex Williamson [this message]
2021-08-03 23:28 ` Bjorn Helgaas

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210803124931.270ca006.alex.williamson@redhat.com \
    --to=alex.williamson@redhat.com \
    --cc=bhelgaas@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=rajatja@google.com \
    --subject='Re: [PATCH] PCI/ACS: Enforce pci=noats with Transaction Blocking' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).