From: Jason Gunthorpe <jgg@nvidia.com>
To: Wei Wang <wei.w.wang@hotmail.com>
Cc: bhelgaas@google.com, jonathan.cameron@huawei.com,
dan.carpenter@linaro.org, akpm@linux-foundation.org,
bp@alien8.de, rdunlap@infradead.org, alex@shazbot.org,
kevin.tian@intel.com, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org
Subject: Re: [PATCH v6 6/6] PCI: Add the enhanced ACS controls check to pci_acs_flags_enabled()
Date: Mon, 30 Mar 2026 10:21:02 -0300 [thread overview]
Message-ID: <20260330132102.GR310919@nvidia.com> (raw)
In-Reply-To: <SEZPR01MB43997A01AC87EC9CEB97077CDC44A@SEZPR01MB4399.apcprd01.prod.exchangelabs.com>
On Thu, Mar 12, 2026 at 05:06:37PM +0800, Wei Wang wrote:
> The enhanced ACS controls introduced by PCIe Gen 5 ensures better device
> isolation. On devices that support the PCI_ACS_ECAP capability, the
> controls are required to be enabled properly:
> - ACS I/O Request Blocking needs to be enabled to avoid unintended
> upstream I/O requests.
> - ACS DSP and USP Memory Target Access Control needs to be set with
> Request Redirect or Request Blocking to ensure the Downstream and
> Upstream Port memory resource ranges are not accessed by upstream
> memory requests.
> - ACS Unclaimed Request Redirect needs to be enabled to ensure accesses to
> areas that lies within a Switch's Upstream Port memory apertures but not
> within any Downstream Port memory apertures get redirected.
>
> To maintain compatibility with legacy devices that lack PCI_ACS_ECAP
> support, pci_acs_enabled() skips checking for the capability.
This seems conservative enough
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Jason
next prev parent reply other threads:[~2026-03-30 13:21 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-12 9:06 [PATCH v6 0/6] PCI: Add support for ACS Enhanced Capability Wei Wang
2026-03-12 9:06 ` [PATCH v6 1/6] PCI: Validate ACS enable flags against device-specific ACS capabilities Wei Wang
2026-03-30 13:09 ` Jason Gunthorpe
2026-03-12 9:06 ` [PATCH v6 2/6] Documentation/kernel-parameters: Add multi-device config_acs example Wei Wang
2026-03-30 13:10 ` Jason Gunthorpe
2026-03-12 9:06 ` [PATCH v6 3/6] PCI: Consolidate delimiter handling into pci_dev_str_match() Wei Wang
2026-03-30 13:11 ` Jason Gunthorpe
2026-05-04 5:31 ` Krzysztof Wilczyński
2026-05-07 13:33 ` Wei Wang
2026-03-12 9:06 ` [PATCH v6 4/6] PCI: Refactor disable_acs_redir and config_acs param handling Wei Wang
2026-03-12 9:06 ` [PATCH v6 5/6] PCI: Enable the enhanced ACS controls introduced by PCI_ACS_ECAP Wei Wang
2026-03-12 9:06 ` [PATCH v6 6/6] PCI: Add the enhanced ACS controls check to pci_acs_flags_enabled() Wei Wang
2026-03-30 13:21 ` Jason Gunthorpe [this message]
2026-03-12 10:59 ` [PATCH v6 0/6] PCI: Add support for ACS Enhanced Capability Wei Wang
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