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From: Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
To: <linux-pci@vger.kernel.org>, <linuxppc-dev@lists.ozlabs.org>
Cc: Bjorn Helgaas <helgaas@kernel.org>, <linux@yadro.com>,
	Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
Subject: [PATCH v5 11/23] PCI: hotplug: movable BARs: Calculate immovable parts of bridge windows
Date: Fri, 16 Aug 2019 19:50:49 +0300
Message-ID: <20190816165101.911-12-s.miroshnichenko@yadro.com> (raw)
In-Reply-To: <20190816165101.911-1-s.miroshnichenko@yadro.com>

When movable BARs are enabled, and if a bridge contains a device with fixed
(IORESOURCE_PCI_FIXED) or immovable BARs, the corresponing windows can't be
moved too far away from their original positions - they must still contain
all the fixed/immovable BARs, like that:

  1) Window position before a bus rescan:

  | <--                    root bridge window                        --> |
  |                                                                      |
  | | <--     bridge window    --> |                                     |
  | | movable BARs | **fixed BAR** |                                     |

  2) Possible valid outcome after rescan and move:

  | <--                    root bridge window                        --> |
  |                                                                      |
  |                | <--     bridge window    --> |                      |
  |                | **fixed BAR** | Movable BARs |                      |

An immovable area of a bridge (separare for IO, MEM and MEM64 window types)
is a range that covers all the fixed and immovable BARs of direct children,
and all the fixed area of children bridges:

  | <--                    root bridge window                        --> |
  |                                                                      |
  |  | <--                  bridge window level 1                --> |   |
  |  | ******** immovable area of this bridge window ********        |   |
  |  |                                                               |   |
  |  | **fixed BAR**  | <--      bridge window level 2    --> | BARs |   |
  |  |                | ***** fixed area of this bridge ***** |      |   |
  |  |                |                                       |      |   |
  |  |                | ***fixed BAR*** |   | ***fixed BAR*** |      |   |

To store these areas, the .immovable_range field has been added to struct
pci_bus. It is filled recursively from leaves to the root before a rescan.

Also make pbus_size_io() and pbus_size_mem() return their usual result OR
the size of an immovable range of according type, depending on which one is
larger.

Signed-off-by: Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
---
 drivers/pci/pci.h       | 14 +++++++
 drivers/pci/probe.c     | 88 +++++++++++++++++++++++++++++++++++++++++
 drivers/pci/setup-bus.c | 17 ++++++++
 include/linux/pci.h     |  6 +++
 4 files changed, 125 insertions(+)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 53249cbc21b6..12add575faf1 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -371,6 +371,20 @@ static inline bool pci_dev_is_disconnected(const struct pci_dev *dev)
 	return dev->error_state == pci_channel_io_perm_failure;
 }
 
+static inline int pci_get_bridge_resource_idx(struct resource *r)
+{
+	int idx = 1;
+
+	if (r->flags & IORESOURCE_IO)
+		idx = 0;
+	else if (!(r->flags & IORESOURCE_PREFETCH))
+		idx = 1;
+	else if (r->flags & IORESOURCE_MEM_64)
+		idx = 2;
+
+	return idx;
+}
+
 /* pci_dev priv_flags */
 #define PCI_DEV_ADDED 0
 #define PCI_DEV_DISABLED_BARS 1
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index bf0a7d1c5d09..5f52a19738aa 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -550,6 +550,7 @@ void pci_read_bridge_bases(struct pci_bus *child)
 static struct pci_bus *pci_alloc_bus(struct pci_bus *parent)
 {
 	struct pci_bus *b;
+	int idx;
 
 	b = kzalloc(sizeof(*b), GFP_KERNEL);
 	if (!b)
@@ -566,6 +567,11 @@ static struct pci_bus *pci_alloc_bus(struct pci_bus *parent)
 	if (parent)
 		b->domain_nr = parent->domain_nr;
 #endif
+	for (idx = 0; idx < PCI_BRIDGE_RESOURCE_NUM; ++idx) {
+		b->immovable_range[idx].start = 0;
+		b->immovable_range[idx].end = 0;
+	}
+
 	return b;
 }
 
@@ -3512,6 +3518,87 @@ static void pci_setup_bridges(struct pci_bus *bus)
 		pci_setup_bridge(bus);
 }
 
+static void pci_bus_update_immovable_range(struct pci_bus *bus)
+{
+	struct pci_dev *dev;
+	int idx;
+	resource_size_t start, end;
+
+	for (idx = 0; idx < PCI_BRIDGE_RESOURCE_NUM; ++idx) {
+		bus->immovable_range[idx].start = 0;
+		bus->immovable_range[idx].end = 0;
+	}
+
+	list_for_each_entry(dev, &bus->devices, bus_list)
+		if (dev->subordinate)
+			pci_bus_update_immovable_range(dev->subordinate);
+
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		int i;
+		bool dev_is_movable = pci_dev_movable_bars_supported(dev);
+		struct pci_bus *child = dev->subordinate;
+
+		for (i = 0; i < PCI_BRIDGE_RESOURCES; ++i) {
+			struct resource *r = &dev->resource[i];
+
+			if (!r->flags || (r->flags & IORESOURCE_UNSET) || !r->parent)
+				continue;
+
+			if (!dev_is_movable || (r->flags & IORESOURCE_PCI_FIXED)) {
+				idx = pci_get_bridge_resource_idx(r);
+				start = bus->immovable_range[idx].start;
+				end = bus->immovable_range[idx].end;
+
+				if (!start || start > r->start)
+					start = r->start;
+				if (end < r->end)
+					end = r->end;
+
+				if (bus->immovable_range[idx].start != start ||
+				    bus->immovable_range[idx].end != end) {
+					dev_dbg(&bus->dev, "Found fixed 0x%llx-0x%llx in %s, expand the fixed bridge window %d to 0x%llx-0x%llx\n",
+						(unsigned long long)r->start,
+						(unsigned long long)r->end,
+						dev_name(&dev->dev), idx,
+						(unsigned long long)start,
+						(unsigned long long)end);
+					bus->immovable_range[idx].start = start;
+					bus->immovable_range[idx].end = end;
+				}
+			}
+		}
+
+		if (child) {
+			for (idx = 0; idx < PCI_BRIDGE_RESOURCE_NUM; ++idx) {
+				struct resource *child_immovable_range =
+					&child->immovable_range[idx];
+
+				if (child_immovable_range->start >=
+				    child_immovable_range->end)
+					continue;
+
+				start = bus->immovable_range[idx].start;
+				end = bus->immovable_range[idx].end;
+
+				if (!start || start > child_immovable_range->start)
+					start = child_immovable_range->start;
+				if (end < child_immovable_range->end)
+					end = child_immovable_range->end;
+
+				if (start < bus->immovable_range[idx].start ||
+				    end > bus->immovable_range[idx].end) {
+					dev_dbg(&bus->dev, "Expand the fixed bridge window %d from %s to 0x%llx-0x%llx\n",
+						idx, dev_name(&child->dev),
+						(unsigned long long)start,
+						(unsigned long long)end);
+					bus->immovable_range[idx].start = start;
+					bus->immovable_range[idx].end = end;
+				}
+			}
+		}
+	}
+}
+
 static struct pci_dev *pci_find_next_new_device(struct pci_bus *bus)
 {
 	struct pci_dev *dev;
@@ -3610,6 +3697,7 @@ unsigned int pci_rescan_bus(struct pci_bus *bus)
 		pci_bus_rescan_prepare(root);
 
 		max = pci_scan_child_bus(root);
+		pci_bus_update_immovable_range(root);
 
 		pci_reassign_root_bus_resources(root);
 
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 33f709095675..420510a1a257 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -882,9 +882,17 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
 	resource_size_t children_add_size = 0;
 	resource_size_t min_align, align;
 
+	resource_size_t fixed_start = bus->immovable_range[0].start;
+	resource_size_t fixed_end = bus->immovable_range[0].end;
+	resource_size_t fixed_size = (fixed_start < fixed_end) ?
+		(fixed_end - fixed_start + 1) : 0;
+
 	if (!b_res)
 		return;
 
+	if (min_size < fixed_size)
+		min_size = fixed_size;
+
 	min_align = window_alignment(bus, IORESOURCE_IO);
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		int i;
@@ -993,6 +1001,15 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
 	resource_size_t children_add_size = 0;
 	resource_size_t children_add_align = 0;
 	resource_size_t add_align = 0;
+	bool is_mem64 = (mask & IORESOURCE_MEM_64);
+
+	resource_size_t fixed_start = bus->immovable_range[is_mem64 ? 2 : 1].start;
+	resource_size_t fixed_end = bus->immovable_range[is_mem64 ? 2 : 1].end;
+	resource_size_t fixed_size = (fixed_start < fixed_end) ?
+		(fixed_end - fixed_start + 1) : 0;
+
+	if (min_size < fixed_size)
+		min_size = fixed_size;
 
 	if (!b_res)
 		return -ENOSPC;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 95a8113c2157..efafbf816fe6 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -581,6 +581,12 @@ struct pci_bus {
 	struct list_head resources;	/* Address space routed to this bus */
 	struct resource busn_res;	/* Bus numbers routed to this bus */
 
+	/*
+	 * If there are fixed or immovable resources in the bridge window, this range
+	 * contains the lowest start address and highest end address of them.
+	 */
+	struct resource immovable_range[PCI_BRIDGE_RESOURCE_NUM];
+
 	struct pci_ops	*ops;		/* Configuration access functions */
 	struct msi_controller *msi;	/* MSI controller */
 	void		*sysdata;	/* Hook for sys-specific extension */
-- 
2.21.0


  parent reply index

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-16 16:50 [PATCH v5 00/23] PCI: Allow BAR movement during hotplug Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 01/23] PCI: Fix race condition in pci_enable/disable_device() Sergey Miroshnichenko
2019-08-22 12:37   ` Marta Rybczynska
2019-09-27 21:59   ` Bjorn Helgaas
2019-09-30  8:53     ` Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 02/23] PCI: Enable bridge's I/O and MEM access for hotplugged devices Sergey Miroshnichenko
2019-09-27 22:01   ` Bjorn Helgaas
2019-08-16 16:50 ` [PATCH v5 03/23] PCI: hotplug: Add a flag for the movable BARs feature Sergey Miroshnichenko
2019-09-27 22:02   ` Bjorn Helgaas
2019-09-30  8:44     ` David Laight
2019-09-30 16:17       ` Sergey Miroshnichenko
2019-09-30 12:59     ` Sergey Miroshnichenko
2019-10-15 22:14       ` Bjorn Helgaas
2019-10-16 15:50         ` Sergey Miroshnichenko
2019-10-16 17:29           ` Bjorn Helgaas
2019-08-16 16:50 ` [PATCH v5 04/23] PCI: Define PCI-specific version of the release_child_resources() Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 05/23] PCI: hotplug: movable BARs: Fix reassigning the released bridge windows Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 06/23] PCI: hotplug: movable BARs: Recalculate all bridge windows during rescan Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 07/23] PCI: hotplug: movable BARs: Don't allow added devices to steal resources Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 08/23] PCI: Include fixed and immovable BARs into the bus size calculating Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 09/23] PCI: Prohibit assigning BARs and bridge windows to non-direct parents Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 10/23] PCI: hotplug: movable BARs: Try to assign unassigned resources only once Sergey Miroshnichenko
2019-08-16 16:50 ` Sergey Miroshnichenko [this message]
2019-08-16 16:50 ` [PATCH v5 12/23] PCI: hotplug: movable BARs: Compute limits for relocated bridge windows Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 13/23] PCI: Make sure bridge windows include their fixed BARs Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 14/23] PCI: Fix assigning the fixed prefetchable resources Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 15/23] PCI: hotplug: movable BARs: Assign fixed and immovable BARs before others Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 16/23] PCI: hotplug: movable BARs: Don't reserve IO/mem bus space Sergey Miroshnichenko
2019-09-04  5:42   ` Oliver O'Halloran
2019-09-04 11:22     ` Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 17/23] powerpc/pci: Fix crash with enabled movable BARs Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 18/23] powerpc/pci: Handle BAR movement Sergey Miroshnichenko
2019-09-04  5:37   ` Oliver O'Halloran
2019-09-06 16:24     ` Sergey Miroshnichenko
2019-09-09 14:02       ` Oliver O'Halloran
2019-08-16 16:50 ` [PATCH v5 19/23] PCI: hotplug: Configure MPS for hot-added bridges during bus rescan Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 20/23] PCI: hotplug: movable BARs: Enable the feature by default Sergey Miroshnichenko
2019-08-16 16:50 ` [PATCH v5 21/23] nvme-pci: Handle movable BARs Sergey Miroshnichenko
2019-08-16 16:51 ` [PATCH v5 22/23] PCI/portdrv: Declare support of " Sergey Miroshnichenko
2019-08-16 16:51 ` [PATCH v5 23/23] PCI: pciehp: movable BARs: Trigger a domain rescan on hp events Sergey Miroshnichenko

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