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From: Sergei Miroshnichenko <s.miroshnichenko@yadro.com>
To: <linux-pci@vger.kernel.org>
Cc: "Bjorn Helgaas" <helgaas@kernel.org>,
	"Lukas Wunner" <lukas@wunner.de>, "Stefan Roese" <sr@denx.de>,
	"Andy Lavr" <andy.lavr@gmail.com>,
	"Christian König" <christian.koenig@amd.com>,
	"Ard Biesheuvel" <ardb@kernel.org>,
	"David Laight" <David.Laight@ACULAB.COM>,
	"Rajat Jain" <rajatja@google.com>,
	linux@yadro.com,
	"Sergei Miroshnichenko" <s.miroshnichenko@yadro.com>
Subject: [PATCH v8 00/24] PCI: Allow BAR movement during boot and hotplug
Date: Mon, 27 Apr 2020 21:23:34 +0300
Message-ID: <20200427182358.2067702-1-s.miroshnichenko@yadro.com> (raw)

Currently PCI hotplug works on top of resources which are usually reserved
not by the kernel, but by BIOS, bootloader, firmware, etc. These resources
are gaps in the address space where BARs of new devices may fit, and extra
bus number per port, so bridges can be hot-added. This series aim the BARs
problem: it shows the kernel how to redistribute them on the run, so the
hotplug becomes predictable and cross-platform. A follow-up patchset will
propose a solution for bus numbers.

To arrange a space for BARs of new hotplugged devices, the kernel can pause
the drivers of working PCI devices and reshuffle the assigned BARs. When a
driver is un-paused by the kernel, it should ioremap() the new addresses of
its BARs.

Drivers indicate their support of the feature by implementing the new hooks
.rescan_prepare() and .rescan_done() in the struct pci_driver. If a driver
doesn't yet support the feature, BARs of its devices will be considered as
immovable and handled in the same way as resources with the PCI_FIXED flag:
they are guaranteed to remain untouched.

Tested on a number of x86_64 machines without any special kernel command
line arguments:
 - PC: i7-5930K + ASUS X99-A;
 - PC: i5-8500 + ASUS Z370-F;
 - Supermicro Super Server/H11SSL-i: AMD EPYC 7251;
 - HP ProLiant DL380 G5: Xeon X5460;
 - Dell Inspiron N5010: i5 M 480;
 - Dell Precision M6600: i7-2920XM.

Also tested on a Power8 (Vesnin) and Power9 (Nicole) ppc64le machines, but
with extra patchset, its next version is to be sent upstream a bit later.

First two patches of this series are independent bugfixes, both are not
related directly to the movable BARs feature, but without them the rest of
this series will not work as expected.

Patches 03-15 implement the essentials of the feature.

Patches 16-21 are performance improvements for movable BARs and pciehp.

Patch 22 enables the feature by default.

Patches 23-24 add movable BARs support to nvme and portdrv.

This patchset is a part of our work on adding support for hotplugging
chains of chassis full of other bridges, NVME drives, SAS HBAs, GPUs, etc.
without special requirements such as Hot-Plug Controller, reservation of
bus numbers or memory regions by firmware, etc.

Added Stefan Roese and Andy Lavr to CC, thank you for trying this on your
hardware!

Added Christian König and Ard Biesheuvel to CC, because of the recent
"PCI: allow pci_resize_resource() to be used on devices on the root bus"
thread, which covers a similar problem.

Changes since v7:
 - Added some documentation;
 - Replaced every occurrence of the word "immovable" with "fixed";
 - Don't touch PNP, ACPI resources anymore;
 - Replaced double rescan with triple rescan:
   * first try every BAR;
   * if that failed, retry without BARs which weren't assigned before;
   * if that failed, retry without BARs of hotplugged devices;
 - Reassign BARs during boot only if BIOS assigned not all requested BARs;
 - Fixed up PCIBIOS_MIN_MEM instead of ignoring it;
 - Now the feature auto-disables in presence of a transparent bridge;
 - Improved support of runtime PM;
 - Fixed issues with incorrectly released bridge windows;
 - Fixed calculating bridge window size.
 
Changes since v6:
 - Added a fix for hotplug on AMD Epyc + Supermicro H11SSL-i by ignoring
   PCIBIOS_MIN_MEM;
 - Fixed a workaround which marks VGA BARs as immovables;
 - Fixed misleading "can't claim BAR ... no compatible bridge window" error
   messages;
 - Refactored the code, reduced the amount of patches;
 - Exclude PowerPC-specific arch patches, they will be sent separately;
 - Disabled for PowerNV by default - waiting for the PCIPOCALYPSE patchset.
 - Fixed reports from the kbuild test robot.

Changes since v5:
 - Simplified the disable flag, now it is "pci=no_movable_buses";
 - More deliberate marking the BARs as immovable;
 - Mark as immovable BARs which are used by unbound drivers;
 - Ignoring BAR assignment by non-kernel program components, so the kernel
   is able now to distribute BARs in optimal and predictable way;
 - Move here PowerNV-specific patches from the older "powerpc/powernv/pci:
   Make hotplug self-sufficient, independent of FW and DT" series;
 - Fix EEH cache rebuilding and PE allocation for PowerNV during rescan.

Changes since v4:
 - Feature is enabled by default (turned on by one of the latest patches);
 - Add pci_dev_movable_bars_supported(dev) instead of marking the immovable
   BARs with the IORESOURCE_PCI_FIXED flag;
 - Set up PCIe bridges during rescan via sysfs, so MPS settings are now
   configured not only during system boot or pcihp events;
 - Allow movement of switch's BARs if claimed by portdrv;
 - Update EEH address caches after rescan for powerpc;
 - Don't disable completely hot-added devices which can't have BARs being
   fit - just disable their BARs, so they are still visible in lspci etc;
 - Clearer names: fixed_range_hard -> immovable_range, fixed_range_soft ->
   realloc_range;
 - Drop the patch for pci_restore_config_space() - fixed by properly using
   the runtime PM.

Changes since v3:
 - Rebased to the upstream, so the patches apply cleanly again.

Changes since v2:
 - Fixed double-assignment of bridge windows;
 - Fixed assignment of fixed prefetched resources;
 - Fixed releasing of fixed resources;
 - Fixed a debug message;
 - Removed auto-enabling the movable BARs for x86 - let's rely on the
   "pcie_movable_bars=force" option for now;
 - Reordered the patches - bugfixes first.

Changes since v1:
 - Add a "pcie_movable_bars={ off | force }" command line argument;
 - Handle the IORESOURCE_PCI_FIXED flag properly;
 - Don't move BARs of devices which don't support the feature;
 - Guarantee that new hotplugged devices will not steal memory from working
   devices by ignoring the failing new devices with the new PCI_DEV_IGNORE
   flag;
 - Add rescan_prepare()+rescan_done() to the struct pci_driver instead of
   using the reset_prepare()+reset_done() from struct pci_error_handlers;
 - Add a bugfix of a race condition;
 - Fixed hotplug in a non-pre-enabled (by BIOS/firmware) bridge;
 - Fix the compatibility of the feature with pm_runtime and D3-state;
 - Hotplug events from pciehp also can move BARs;
 - Add support of the feature to the NVME driver.

Sergei Miroshnichenko (24):
  PCI: Fix race condition in pci_enable/disable_device()
  PCI: Ensure a bridge has I/O and MEM access for hot-added devices
  PCI: hotplug: Initial support of the movable BARs feature
  PCI: Add version of release_child_resources() aware of fixed BARs
  PCI: hotplug: Fix reassigning the released BARs
  PCI: hotplug: Recalculate every bridge window during rescan
  PCI: hotplug: Don't allow hot-added devices to steal resources
  PCI: Reassign BARs if BIOS/bootloader had assigned not all of them
  PCI: hotplug: Try to reassign movable BARs only once
  PCI: hotplug: Calculate fixed parts of bridge windows
  PCI: Include fixed BARs into the bus size calculating
  PCI: hotplug: movable BARs: Compute limits for relocated bridge
    windows
  PCI: Make sure bridge windows include their fixed BARs
  PCI: hotplug: Add support of fixed BARs to pci_assign_resource()
  PCI: hotplug: Sort fixed BARs before assignment
  x86/PCI/ACPI: Fix up PCIBIOS_MIN_MEM if value computed from e820 is
    invalid
  PCI: hotplug: Configure MPS after manual bus rescan
  PCI: hotplug: Don't disable the released bridge windows immediately
  PCI: pciehp: Trigger a domain rescan on hp events when enabled movable
    BARs
  PCI: Don't claim fixed BARs
  PCI: hotplug: Don't reserve bus space when enabled movable BARs
  PCI: hotplug: Enable the movable BARs feature by default
  PCI/portdrv: Declare support of movable BARs
  nvme-pci: Handle movable BARs

 Documentation/PCI/pci.rst                     |  55 +++
 .../admin-guide/kernel-parameters.txt         |   1 +
 arch/powerpc/platforms/powernv/pci.c          |   2 +
 arch/powerpc/platforms/pseries/setup.c        |   2 +
 arch/x86/pci/acpi.c                           |  15 +
 drivers/nvme/host/pci.c                       |  21 +-
 drivers/pci/bus.c                             |   2 +-
 drivers/pci/hotplug/pciehp_pci.c              |   5 +
 drivers/pci/iov.c                             |   2 +
 drivers/pci/pci.c                             |  33 +-
 drivers/pci/pci.h                             |  33 ++
 drivers/pci/pcie/portdrv_pci.c                |  11 +
 drivers/pci/probe.c                           | 399 +++++++++++++++++-
 drivers/pci/setup-bus.c                       | 301 ++++++++++---
 drivers/pci/setup-res.c                       |  75 +++-
 include/linux/pci.h                           |  20 +
 16 files changed, 905 insertions(+), 72 deletions(-)


base-commit: 6a8b55ed4056ea5559ebe4f6a4b247f627870d4c
-- 
2.24.1


             reply index

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-27 18:23 Sergei Miroshnichenko [this message]
2020-04-27 18:23 ` [PATCH v8 01/24] PCI: Fix race condition in pci_enable/disable_device() Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 02/24] PCI: Ensure a bridge has I/O and MEM access for hot-added devices Sergei Miroshnichenko
2020-04-29  6:30   ` kbuild test robot
2020-04-27 18:23 ` [PATCH v8 03/24] PCI: hotplug: Initial support of the movable BARs feature Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 04/24] PCI: Add version of release_child_resources() aware of fixed BARs Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 05/24] PCI: hotplug: Fix reassigning the released BARs Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 06/24] PCI: hotplug: Recalculate every bridge window during rescan Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 07/24] PCI: hotplug: Don't allow hot-added devices to steal resources Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 08/24] PCI: Reassign BARs if BIOS/bootloader had assigned not all of them Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 09/24] PCI: hotplug: Try to reassign movable BARs only once Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 10/24] PCI: hotplug: Calculate fixed parts of bridge windows Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 11/24] PCI: Include fixed BARs into the bus size calculating Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 12/24] PCI: hotplug: movable BARs: Compute limits for relocated bridge windows Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 13/24] PCI: Make sure bridge windows include their fixed BARs Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 14/24] PCI: hotplug: Add support of fixed BARs to pci_assign_resource() Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 15/24] PCI: hotplug: Sort fixed BARs before assignment Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 16/24] x86/PCI/ACPI: Fix up PCIBIOS_MIN_MEM if value computed from e820 is invalid Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 17/24] PCI: hotplug: Configure MPS after manual bus rescan Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 18/24] PCI: hotplug: Don't disable the released bridge windows immediately Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 19/24] PCI: pciehp: Trigger a domain rescan on hp events when enabled movable BARs Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 20/24] PCI: Don't claim fixed BARs Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 21/24] PCI: hotplug: Don't reserve bus space when enabled movable BARs Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 22/24] PCI: hotplug: Enable the movable BARs feature by default Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 23/24] PCI/portdrv: Declare support of movable BARs Sergei Miroshnichenko
2020-04-27 18:23 ` [PATCH v8 24/24] nvme-pci: Handle " Sergei Miroshnichenko
2020-04-28 12:59 ` [PATCH v8 00/24] PCI: Allow BAR movement during boot and hotplug Christian König
2020-05-04  9:30   ` Sergei Miroshnichenko
2020-08-10 22:21 ` Bjorn Helgaas

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