LinuxPPC-Dev Archive mirror
 help / color / mirror / Atom feed
From: Lukas Wunner <lukas@wunner.de>
To: Bjorn Helgaas <helgaas@kernel.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>
Cc: Riana Tauro <riana.tauro@intel.com>,
	"Sean C. Dardis" <sean.c.dardis@intel.com>,
	Farhan Ali <alifm@linux.ibm.com>,
	Benjamin Block <bblock@linux.ibm.com>,
	Niklas Schnelle <schnelle@linux.ibm.com>,
	Alek Du <alek.du@intel.com>,
	"Mahesh J Salgaonkar" <mahesh@linux.ibm.com>,
	Oliver OHalloran <oohall@gmail.com>,
	linuxppc-dev@lists.ozlabs.org, linux-pci@vger.kernel.org,
	Giovanni Cabiddu <giovanni.cabiddu@intel.com>,
	qat-linux@intel.com, Dave Jiang <dave.jiang@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Subject: [PATCH 0/2] PCI: Universal error recoverability of devices
Date: Sun, 12 Oct 2025 15:25:00 +0200	[thread overview]
Message-ID: <cover.1760274044.git.lukas@wunner.de> (raw)

When PCI devices are reset -- either to recover from an error or
after a D3hot/D3cold transition -- their Config Space needs to be
restored.

D3hot/D3cold transitions happen under the control of the kernel,
hence it is able to save Config Space before and restore it afterwards.

However errors may occur unexpectedly and it may then be impossible
to save Config Space because the device may be inaccessible (e.g. DPC)
or Config Space may be corrupted.  So it must be saved ahead of time.

This isn't done consistently because the PCI core doesn't take care
of it and only a subset of drivers do.  The situation is aggravated
by the behavior of pci_restore_state(), which only allows restoring
Config Space once and invalidates the saved copy afterwards.

Solve all these problems by saving an initial copy of Config Space
on device addition which drivers may update if they change registers.
Modify pci_restore_state() to allow using the saved copy indefinitely
and drop all the workarounds for its previous behavior that have
accumulated in the tree.

Lukas Wunner (2):
  PCI: Ensure error recoverability at all times
  treewide: Drop pci_save_state() after pci_restore_state()

 drivers/crypto/intel/qat/qat_common/adf_aer.c    | 2 --
 drivers/dma/ioat/init.c                          | 1 -
 drivers/net/ethernet/broadcom/bnx2.c             | 2 --
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c | 1 -
 drivers/net/ethernet/broadcom/tg3.c              | 1 -
 drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c  | 1 -
 drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c  | 2 --
 drivers/net/ethernet/hisilicon/hibmcge/hbg_err.c | 1 -
 drivers/net/ethernet/intel/e1000e/netdev.c       | 1 -
 drivers/net/ethernet/intel/fm10k/fm10k_pci.c     | 6 ------
 drivers/net/ethernet/intel/i40e/i40e_main.c      | 1 -
 drivers/net/ethernet/intel/ice/ice_main.c        | 2 --
 drivers/net/ethernet/intel/igb/igb_main.c        | 2 --
 drivers/net/ethernet/intel/igc/igc_main.c        | 2 --
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c    | 1 -
 drivers/net/ethernet/mellanox/mlx4/main.c        | 1 -
 drivers/net/ethernet/mellanox/mlx5/core/main.c   | 1 -
 drivers/net/ethernet/meta/fbnic/fbnic_pci.c      | 1 -
 drivers/net/ethernet/microchip/lan743x_main.c    | 1 -
 drivers/net/ethernet/myricom/myri10ge/myri10ge.c | 4 ----
 drivers/net/ethernet/neterion/s2io.c             | 1 -
 drivers/pci/bus.c                                | 7 +++++++
 drivers/pci/pci.c                                | 3 ---
 drivers/pci/pcie/portdrv.c                       | 1 -
 drivers/pci/probe.c                              | 2 --
 drivers/scsi/bfa/bfad.c                          | 1 -
 drivers/scsi/csiostor/csio_init.c                | 1 -
 drivers/scsi/ipr.c                               | 1 -
 drivers/scsi/lpfc/lpfc_init.c                    | 6 ------
 drivers/scsi/qla2xxx/qla_os.c                    | 5 -----
 drivers/scsi/qla4xxx/ql4_os.c                    | 5 -----
 drivers/tty/serial/8250/8250_pci.c               | 1 -
 drivers/tty/serial/jsm/jsm_driver.c              | 1 -
 33 files changed, 7 insertions(+), 62 deletions(-)

-- 
2.51.0



             reply	other threads:[~2025-10-12 13:25 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-12 13:25 Lukas Wunner [this message]
2025-10-12 13:25 ` [PATCH 1/2] PCI: Ensure error recoverability at all times Lukas Wunner
2025-11-12 22:38   ` Bjorn Helgaas
2025-11-13  9:38     ` Lukas Wunner
2025-11-13 16:15       ` Bjorn Helgaas
2025-11-14 18:58         ` Lukas Wunner
2025-11-14 23:39           ` Bjorn Helgaas
2025-11-19 10:02             ` Lukas Wunner
2025-11-21 17:40         ` Lukas Wunner
2025-11-24 22:11           ` Bjorn Helgaas
2025-11-13 20:49   ` Rafael J. Wysocki
2025-11-13 21:03     ` Rafael J. Wysocki
2025-10-12 13:25 ` [PATCH 2/2] treewide: Drop pci_save_state() after pci_restore_state() Lukas Wunner
2025-11-05 14:22   ` Dave Jiang
2025-11-05 14:33   ` Giovanni Cabiddu
2025-11-24 23:13   ` Bjorn Helgaas
2025-11-14 23:45 ` [PATCH 0/2] PCI: Universal error recoverability of devices 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=cover.1760274044.git.lukas@wunner.de \
    --to=lukas@wunner.de \
    --cc=James.Bottomley@HansenPartnership.com \
    --cc=alek.du@intel.com \
    --cc=alifm@linux.ibm.com \
    --cc=andrew+netdev@lunn.ch \
    --cc=bblock@linux.ibm.com \
    --cc=dave.jiang@intel.com \
    --cc=davem@davemloft.net \
    --cc=edumazet@google.com \
    --cc=giovanni.cabiddu@intel.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=helgaas@kernel.org \
    --cc=jirislaby@kernel.org \
    --cc=kuba@kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mahesh@linux.ibm.com \
    --cc=martin.petersen@oracle.com \
    --cc=oohall@gmail.com \
    --cc=pabeni@redhat.com \
    --cc=qat-linux@intel.com \
    --cc=rafael@kernel.org \
    --cc=riana.tauro@intel.com \
    --cc=schnelle@linux.ibm.com \
    --cc=sean.c.dardis@intel.com \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
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 read-only IMAP folder(s) and NNTP newsgroup(s).