From: Richard Cheng <icheng@nvidia.com>
To: Srirangan Madhavan <smadhavan@nvidia.com>
Cc: Alison Schofield <alison.schofield@intel.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Dan Williams <djbw@kernel.org>,
Dave Jiang <dave.jiang@intel.com>,
Davidlohr Bueso <dave@stgolabs.net>,
Ira Weiny <ira.weiny@intel.com>,
Jonathan Cameron <jic23@kernel.org>,
Vishal Verma <vishal.l.verma@intel.com>,
linux-cxl@vger.kernel.org, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org,
Alex Williamson <alex.williamson@redhat.com>,
vsethi@nvidia.com, alwilliamson@nvidia.com,
Sai Yashwanth Reddy Kancherla <skancherla@nvidia.com>,
Vishal Aslot <vaslot@nvidia.com>,
Manish Honap <mhonap@nvidia.com>, Jiandi An <jan@nvidia.com>,
linux-tegra@vger.kernel.org
Subject: Re: [PATCH v11 08/12] PCI/CXL: Reject CXL Reset on multifunction devices
Date: Fri, 4 Sep 2026 17:26:29 +0800 [thread overview]
Message-ID: <apqONsm7xxFqtC5U@MWDK4CY14F> (raw)
In-Reply-To: <20260902072804.665639-9-smadhavan@nvidia.com>
On Wed, Sep 02, 2026 at 07:28:00AM +0800, Srirangan Madhavan wrote:
> CXL Reset can be exposed as a PCI function reset method only when the
> reset is function-scoped. PCI reset-method probing runs during
> enumeration, so walking sibling functions there can race with functions
> that have not been added to the bus yet.
>
> Reject multifunction devices for now instead of trying to infer reset
> scope from sibling state. Systems that can prove a multifunction device
> has function-scoped CXL Reset can be enabled later.
>
> Signed-off-by: Srirangan Madhavan <smadhavan@nvidia.com>
> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> ---
> drivers/cxl/core/resource.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/cxl/core/resource.c b/drivers/cxl/core/resource.c
> index 13bd0c3faf7e..79227ce70169 100644
> --- a/drivers/cxl/core/resource.c
> +++ b/drivers/cxl/core/resource.c
> @@ -979,6 +979,9 @@ int cxl_reset_function(struct pci_dev *pdev, bool probe)
> if (dvsec < 0)
> return dvsec;
>
> + if (pdev->multifunction)
> + return -ENOTTY;
> +
> if (probe)
> return 0;
>
Hmm a PF can have a single-function PCI header while having many enabled VFs,
and VFs enablement can change after reset-method probing.
Since CXL Reset can affect VFs, do we have the mechanism to quiescie all VF?
Best regards,
Richard Cheng.
> --
> 2.43.0
>
next prev parent reply other threads:[~2026-09-04 9:26 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-02 7:27 [PATCH v11 00/12] PCI/CXL: Add CXL reset support for Type 2 devices Srirangan Madhavan
2026-09-02 7:27 ` [PATCH v11 01/12] cxl: Move HDM decoder programming helpers Srirangan Madhavan
2026-09-02 7:27 ` [PATCH v11 02/12] cxl: Make HDM commit helpers available to reset code Srirangan Madhavan
2026-09-02 7:27 ` [PATCH v11 03/12] cxl: Share HDM decoder decode logic Srirangan Madhavan
2026-09-02 7:27 ` [PATCH v11 04/12] cxl: Cache decoder settings on PCI devices Srirangan Madhavan
2026-09-02 7:27 ` [PATCH v11 05/12] cxl: Cache endpoint decoder settings during PCI enumeration Srirangan Madhavan
2026-09-02 14:03 ` Li Ming
2026-09-02 7:27 ` [PATCH v11 06/12] cxl: Add CXL Device Reset helper Srirangan Madhavan
2026-09-02 7:27 ` [PATCH v11 07/12] cxl: Validate HDM ranges before CXL reset Srirangan Madhavan
2026-09-04 9:19 ` Richard Cheng
2026-09-02 7:28 ` [PATCH v11 08/12] PCI/CXL: Reject CXL Reset on multifunction devices Srirangan Madhavan
2026-09-04 9:26 ` Richard Cheng [this message]
2026-09-02 7:28 ` [PATCH v11 09/12] cxl: Restore CXL HDM state after PCI reset Srirangan Madhavan
2026-09-04 9:23 ` Richard Cheng
2026-09-02 7:28 ` [PATCH v11 10/12] PCI/CXL: Expose CXL Reset as a PCI reset method Srirangan Madhavan
2026-09-02 7:28 ` [PATCH v11 11/12] Documentation/ABI: Document CXL Reset " Srirangan Madhavan
2026-09-02 7:28 ` [PATCH v11 12/12] PCI/CXL: Restore HDM state after CXL bus reset Srirangan Madhavan
2026-09-04 9:15 ` [PATCH v11 00/12] PCI/CXL: Add CXL reset support for Type 2 devices Richard Cheng
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