[PATCH v2 0/6] PCI: Allow for future resource expansion on initial root bus scan

[PATCH v2 0/6] PCI: Allow for future resource expansion on initial root bus scan

[Mika Westerberg]

Hi,

The series works around an issue found on some Dell systems where
booting with Thunderbolt/USB4 devices connected the BIOS leaves some of
the PCIe devices unconfigured. If the connected devices that are not
configured have PCIe hotplug ports as well the initial root bus scan
only reserves the minimum amount of resources to them making any
expansion happening later impossible.

We do already distribute the "spare" resources between hotplug ports on
hot-add but we have not done that upon the initial scan. The first four
patches make the initial root bus scan path to do the same.

The additional patches are just a small cleanups that can be applied
separately too.

The related bug: https://bugzilla.kernel.org/show_bug.cgi?id=216000.

The previous version of the patch series can be found here:

  https://lore.kernel.org/linux-pci/20220816100740.68667-1-mika.westerberg@linux.intel.com/

Changes from the previous version:

  * Split patch 3 into two: move and then the actual fix as suggested by
    Andy.
  * Fold the two whitespace fixes into one patch.
  * Added tags from Chris and Andy.

Mika Westerberg (6):
  PCI: Fix used_buses calculation in pci_scan_child_bus_extend()
  PCI: Pass available buses also when the bridge is already configured
  PCI: Move pci_assign_unassigned_root_bus_resources()
  PCI: Distribute available resources for root buses too
  PCI: Fix whitespace and indentation
  PCI: Fix typo in pci_scan_child_bus_extend()

 drivers/pci/probe.c     |  13 +-
 drivers/pci/setup-bus.c | 290 ++++++++++++++++++++++++----------------
 2 files changed, 181 insertions(+), 122 deletions(-)

-- 
2.35.1

[PATCH v2 1/6] PCI: Fix used_buses calculation in pci_scan_child_bus_extend()

[Mika Westerberg]

The 'cmax' and 'max' are in wrong order and that might cause the
used_buses to become negative in certain cases. It should be the same as
we do in the block following this one. Fix this.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216000
Fixes: 3374c545c27c ("PCI: Account for all bridges on bus when distributing bus numbers")
Reported-by: Chris Chiu <chris.chiu@canonical.com>
Tested-by: Chris Chiu <chris.chiu@canonical.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/pci/probe.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index c5286b027f00..4f940dcd102c 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2920,8 +2920,8 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus,
 		 * hotplug bridges too much during the second scan below.
 		 */
 		used_buses++;
-		if (cmax - max > 1)
-			used_buses += cmax - max - 1;
+		if (max - cmax > 1)
+			used_buses += max - cmax - 1;
 	}
 
 	/* Scan bridges that need to be reconfigured */
-- 
2.35.1

[PATCH v2 2/6] PCI: Pass available buses also when the bridge is already configured

[Mika Westerberg]

If some part of the PCI topology is already configured (by the boot
firmware) but not all, and it includes hotplug bridges, we may need to
extend the bus resources of those bridges to accommondate any future
hotplugs too - in the same way we already do with normal hotplug case.

For this reason pass the available busses to pci_scan_child_bus_extend()
even when the bridge in question is already configured. This allows the
bus allocation code to use these available buses to extend the possible
hotplug bridges below.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216000
Reported-by: Chris Chiu <chris.chiu@canonical.com>
Tested-by: Chris Chiu <chris.chiu@canonical.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/pci/probe.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 4f940dcd102c..86130926a74f 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1297,7 +1297,7 @@ static int pci_scan_bridge_extend(struct pci_bus *bus, struct pci_dev *dev,
 
 	if ((secondary || subordinate) && !pcibios_assign_all_busses() &&
 	    !is_cardbus && !broken) {
-		unsigned int cmax;
+		unsigned int cmax, buses;
 
 		/*
 		 * Bus already configured by firmware, process it in the
@@ -1322,7 +1322,8 @@ static int pci_scan_bridge_extend(struct pci_bus *bus, struct pci_dev *dev,
 			child->bridge_ctl = bctl;
 		}
 
-		cmax = pci_scan_child_bus(child);
+		buses = subordinate - secondary;
+		cmax = pci_scan_child_bus_extend(child, buses);
 		if (cmax > subordinate)
 			pci_warn(dev, "bridge has subordinate %02x but max busn %02x\n",
 				 subordinate, cmax);
-- 
2.35.1

[PATCH v2 3/6] PCI: Move pci_assign_unassigned_root_bus_resources()

[Mika Westerberg]

We need to be able to call pci_bridge_distribute_available_resources()
from this function so move it accordingly to avoid need for forward
declaration.

No functional impact.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/pci/setup-bus.c | 226 ++++++++++++++++++++--------------------
 1 file changed, 113 insertions(+), 113 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 8cb68e6f6ef9..3b981da0fb4e 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1745,119 +1745,6 @@ static enum enable_type pci_realloc_detect(struct pci_bus *bus,
 }
 #endif
 
-/*
- * First try will not touch PCI bridge res.
- * Second and later try will clear small leaf bridge res.
- * Will stop till to the max depth if can not find good one.
- */
-void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus)
-{
-	LIST_HEAD(realloc_head);
-	/* List of resources that want additional resources */
-	struct list_head *add_list = NULL;
-	int tried_times = 0;
-	enum release_type rel_type = leaf_only;
-	LIST_HEAD(fail_head);
-	struct pci_dev_resource *fail_res;
-	int pci_try_num = 1;
-	enum enable_type enable_local;
-
-	/* Don't realloc if asked to do so */
-	enable_local = pci_realloc_detect(bus, pci_realloc_enable);
-	if (pci_realloc_enabled(enable_local)) {
-		int max_depth = pci_bus_get_depth(bus);
-
-		pci_try_num = max_depth + 1;
-		dev_info(&bus->dev, "max bus depth: %d pci_try_num: %d\n",
-			 max_depth, pci_try_num);
-	}
-
-again:
-	/*
-	 * Last try will use add_list, otherwise will try good to have as must
-	 * have, so can realloc parent bridge resource
-	 */
-	if (tried_times + 1 == pci_try_num)
-		add_list = &realloc_head;
-	/*
-	 * Depth first, calculate sizes and alignments of all subordinate buses.
-	 */
-	__pci_bus_size_bridges(bus, add_list);
-
-	/* Depth last, allocate resources and update the hardware. */
-	__pci_bus_assign_resources(bus, add_list, &fail_head);
-	if (add_list)
-		BUG_ON(!list_empty(add_list));
-	tried_times++;
-
-	/* Any device complain? */
-	if (list_empty(&fail_head))
-		goto dump;
-
-	if (tried_times >= pci_try_num) {
-		if (enable_local == undefined)
-			dev_info(&bus->dev, "Some PCI device resources are unassigned, try booting with pci=realloc\n");
-		else if (enable_local == auto_enabled)
-			dev_info(&bus->dev, "Automatically enabled pci realloc, if you have problem, try booting with pci=realloc=off\n");
-
-		free_list(&fail_head);
-		goto dump;
-	}
-
-	dev_info(&bus->dev, "No. %d try to assign unassigned res\n",
-		 tried_times + 1);
-
-	/* Third times and later will not check if it is leaf */
-	if ((tried_times + 1) > 2)
-		rel_type = whole_subtree;
-
-	/*
-	 * Try to release leaf bridge's resources that doesn't fit resource of
-	 * child device under that bridge.
-	 */
-	list_for_each_entry(fail_res, &fail_head, list)
-		pci_bus_release_bridge_resources(fail_res->dev->bus,
-						 fail_res->flags & PCI_RES_TYPE_MASK,
-						 rel_type);
-
-	/* Restore size and flags */
-	list_for_each_entry(fail_res, &fail_head, list) {
-		struct resource *res = fail_res->res;
-		int idx;
-
-		res->start = fail_res->start;
-		res->end = fail_res->end;
-		res->flags = fail_res->flags;
-
-		if (pci_is_bridge(fail_res->dev)) {
-			idx = res - &fail_res->dev->resource[0];
-			if (idx >= PCI_BRIDGE_RESOURCES &&
-			    idx <= PCI_BRIDGE_RESOURCE_END)
-				res->flags = 0;
-		}
-	}
-	free_list(&fail_head);
-
-	goto again;
-
-dump:
-	/* Dump the resource on buses */
-	pci_bus_dump_resources(bus);
-}
-
-void __init pci_assign_unassigned_resources(void)
-{
-	struct pci_bus *root_bus;
-
-	list_for_each_entry(root_bus, &pci_root_buses, node) {
-		pci_assign_unassigned_root_bus_resources(root_bus);
-
-		/* Make sure the root bridge has a companion ACPI device */
-		if (ACPI_HANDLE(root_bus->bridge))
-			acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
-	}
-}
-
 static void adjust_bridge_window(struct pci_dev *bridge, struct resource *res,
 				 struct list_head *add_list,
 				 resource_size_t new_size)
@@ -2047,6 +1934,119 @@ static void pci_bridge_distribute_available_resources(struct pci_dev *bridge,
 					       available_mmio_pref);
 }
 
+/*
+ * First try will not touch PCI bridge res.
+ * Second and later try will clear small leaf bridge res.
+ * Will stop till to the max depth if can not find good one.
+ */
+void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus)
+{
+	LIST_HEAD(realloc_head);
+	/* List of resources that want additional resources */
+	struct list_head *add_list = NULL;
+	int tried_times = 0;
+	enum release_type rel_type = leaf_only;
+	LIST_HEAD(fail_head);
+	struct pci_dev_resource *fail_res;
+	int pci_try_num = 1;
+	enum enable_type enable_local;
+
+	/* Don't realloc if asked to do so */
+	enable_local = pci_realloc_detect(bus, pci_realloc_enable);
+	if (pci_realloc_enabled(enable_local)) {
+		int max_depth = pci_bus_get_depth(bus);
+
+		pci_try_num = max_depth + 1;
+		dev_info(&bus->dev, "max bus depth: %d pci_try_num: %d\n",
+			 max_depth, pci_try_num);
+	}
+
+again:
+	/*
+	 * Last try will use add_list, otherwise will try good to have as must
+	 * have, so can realloc parent bridge resource
+	 */
+	if (tried_times + 1 == pci_try_num)
+		add_list = &realloc_head;
+	/*
+	 * Depth first, calculate sizes and alignments of all subordinate buses.
+	 */
+	__pci_bus_size_bridges(bus, add_list);
+
+	/* Depth last, allocate resources and update the hardware. */
+	__pci_bus_assign_resources(bus, add_list, &fail_head);
+	if (add_list)
+		BUG_ON(!list_empty(add_list));
+	tried_times++;
+
+	/* Any device complain? */
+	if (list_empty(&fail_head))
+		goto dump;
+
+	if (tried_times >= pci_try_num) {
+		if (enable_local == undefined)
+			dev_info(&bus->dev, "Some PCI device resources are unassigned, try booting with pci=realloc\n");
+		else if (enable_local == auto_enabled)
+			dev_info(&bus->dev, "Automatically enabled pci realloc, if you have problem, try booting with pci=realloc=off\n");
+
+		free_list(&fail_head);
+		goto dump;
+	}
+
+	dev_info(&bus->dev, "No. %d try to assign unassigned res\n",
+		 tried_times + 1);
+
+	/* Third times and later will not check if it is leaf */
+	if ((tried_times + 1) > 2)
+		rel_type = whole_subtree;
+
+	/*
+	 * Try to release leaf bridge's resources that doesn't fit resource of
+	 * child device under that bridge.
+	 */
+	list_for_each_entry(fail_res, &fail_head, list)
+		pci_bus_release_bridge_resources(fail_res->dev->bus,
+						 fail_res->flags & PCI_RES_TYPE_MASK,
+						 rel_type);
+
+	/* Restore size and flags */
+	list_for_each_entry(fail_res, &fail_head, list) {
+		struct resource *res = fail_res->res;
+		int idx;
+
+		res->start = fail_res->start;
+		res->end = fail_res->end;
+		res->flags = fail_res->flags;
+
+		if (pci_is_bridge(fail_res->dev)) {
+			idx = res - &fail_res->dev->resource[0];
+			if (idx >= PCI_BRIDGE_RESOURCES &&
+			    idx <= PCI_BRIDGE_RESOURCE_END)
+				res->flags = 0;
+		}
+	}
+	free_list(&fail_head);
+
+	goto again;
+
+dump:
+	/* Dump the resource on buses */
+	pci_bus_dump_resources(bus);
+}
+
+void __init pci_assign_unassigned_resources(void)
+{
+	struct pci_bus *root_bus;
+
+	list_for_each_entry(root_bus, &pci_root_buses, node) {
+		pci_assign_unassigned_root_bus_resources(root_bus);
+
+		/* Make sure the root bridge has a companion ACPI device */
+		if (ACPI_HANDLE(root_bus->bridge))
+			acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
+	}
+}
+
 void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
 {
 	struct pci_bus *parent = bridge->subordinate;
-- 
2.35.1

[PATCH v2 4/6] PCI: Distribute available resources for root buses too

[Mika Westerberg]

Currently we distribute the spare resources only upon hot-add so if
there are PCI devices connected already when the initial root bus scan
is done, and they have not been fully configured by the BIOS, we may end
up allocating resources just enough to cover only what is currently
there. If some of those devices are hotplug bridges themselves we do not
leave any additional resource space for future expansion.

For this reason distribute the available resources for root buses too to
make this work the same way we do in the normal hotplug case.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216000
Reported-by: Chris Chiu <chris.chiu@canonical.com>
Tested-by: Chris Chiu <chris.chiu@canonical.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/pci/setup-bus.c | 62 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 3b981da0fb4e..df9fc974b313 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1768,7 +1768,10 @@ static void adjust_bridge_window(struct pci_dev *bridge, struct resource *res,
 	}
 
 	res->end = res->start + new_size - 1;
-	remove_from_list(add_list, res);
+
+	/* If the resource is part of the add_list remove it now */
+	if (add_list)
+		remove_from_list(add_list, res);
 }
 
 static void pci_bus_distribute_available_resources(struct pci_bus *bus,
@@ -1923,6 +1926,8 @@ static void pci_bridge_distribute_available_resources(struct pci_dev *bridge,
 	if (!bridge->is_hotplug_bridge)
 		return;
 
+	pci_dbg(bridge, "distributing available resources\n");
+
 	/* Take the initial extra resources from the hotplug port */
 	available_io = bridge->resource[PCI_BRIDGE_IO_WINDOW];
 	available_mmio = bridge->resource[PCI_BRIDGE_MEM_WINDOW];
@@ -1934,6 +1939,59 @@ static void pci_bridge_distribute_available_resources(struct pci_dev *bridge,
 					       available_mmio_pref);
 }
 
+static bool pci_bridge_resources_not_assigned(struct pci_dev *dev)
+{
+	const struct resource *r;
+
+	/*
+	 * Check the child device's resources and if they are not yet
+	 * assigned it means we are configuring them (not the boot
+	 * firmware) so we should be able to extend the upstream
+	 * bridge's (that's the hotplug downstream PCIe port) resources
+	 * in the same way we do with the normal hotplug case.
+	 */
+	r = &dev->resource[PCI_BRIDGE_IO_WINDOW];
+	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
+		return false;
+	r = &dev->resource[PCI_BRIDGE_MEM_WINDOW];
+	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
+		return false;
+	r = &dev->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
+	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
+		return false;
+
+	return true;
+}
+
+static void pci_root_bus_distribute_available_resources(struct pci_bus *bus,
+							struct list_head *add_list)
+{
+	struct pci_dev *dev, *bridge = bus->self;
+
+	for_each_pci_bridge(dev, bus) {
+		struct pci_bus *b;
+
+		b = dev->subordinate;
+		if (!b)
+			continue;
+
+		/*
+		 * Need to check "bridge" here too because it is NULL
+		 * in case of root bus.
+		 */
+		if (bridge && pci_bridge_resources_not_assigned(dev)) {
+			pci_bridge_distribute_available_resources(bridge, add_list);
+			/*
+			 * There is only PCIe upstream port on the bus
+			 * so we don't need to go futher.
+			 */
+			return;
+		}
+
+		pci_root_bus_distribute_available_resources(b, add_list);
+	}
+}
+
 /*
  * First try will not touch PCI bridge res.
  * Second and later try will clear small leaf bridge res.
@@ -1973,6 +2031,8 @@ void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus)
 	 */
 	__pci_bus_size_bridges(bus, add_list);
 
+	pci_root_bus_distribute_available_resources(bus, add_list);
+
 	/* Depth last, allocate resources and update the hardware. */
 	__pci_bus_assign_resources(bus, add_list, &fail_head);
 	if (add_list)
-- 
2.35.1

Regression: Re: [PATCH v2 4/6] PCI: Distribute available resources for root buses too

[Jonathan Cameron]

On Mon,  5 Sep 2022 11:02:30 +0300
Mika Westerberg <mika.westerberg@linux.intel.com> wrote:

> Currently we distribute the spare resources only upon hot-add so if
> there are PCI devices connected already when the initial root bus scan
> is done, and they have not been fully configured by the BIOS, we may end
> up allocating resources just enough to cover only what is currently
> there. If some of those devices are hotplug bridges themselves we do not
> leave any additional resource space for future expansion.
> 
> For this reason distribute the available resources for root buses too to
> make this work the same way we do in the normal hotplug case.
> 
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=216000
> Reported-by: Chris Chiu <chris.chiu@canonical.com>
> Tested-by: Chris Chiu <chris.chiu@canonical.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> ---

Early days, but I have a regression that's bisecting to this patch
after I did an optimistic checkout of mainline mid merge window.

Initial platform was QEMU emulation of CXL on arm64 with EDK2 / ACPI etc.
That uses an extended version of the PCI eXpander Bus (PXB) with extended
version of the emulated pci root ports.  Particular test was

1 PXB, 2 RP, below first RP switch USP, with two functions (USP and
a stand along switch CCI), below that 4 DSP each with a CXL type 3 device.

Clearly something wrong with the error handling in CXL code as it goes boom
spectacularly.  I'll address that separately.  Anyhow, setup way to complex
to debug easily. 

Anyhow to make this easier for others to poke I set up equivalent with pxb-pcie
etc and it happens there.  Everything works with the exception of additional
functions on USP.

Next up in minimal test case (could be more minimal but I'm lazy) is 

../qemu/bin/native/aarch64-softmmu/qemu-system-aarch64 -M virt,nvdimm=on,gic-version=3,cxl=on -m 4g,maxmem=8G,slots=8 -cpu max -smp 4 \
 -kernel Image \
 -drive if=none,file=full.qcow2,format=qcow2,id=hd \
 -device pcie-root-port,id=root_port1 -device virtio-blk-pci,drive=hd \
 -netdev type=user,id=mynet,hostfwd=tcp::5555-:22 \
 -device virtio-net-pci,netdev=mynet,id=bob \
 -nographic -no-reboot -append 'earlycon root=/dev/vda2 fsck.mode=skip tp_printk maxcpus=4' \
 -monitor telnet:127.0.0.1:1235,server,nowait -bios QEMU_EFI.fd \
 -object memory-backend-ram,size=4G,id=mem0 \
 -numa node,nodeid=0,cpus=0-3,memdev=mem0 \
# Interesting part follows:
 -device pcie-root-port,port=0,id=root_port13,chassis=0,slot=2 \
 -device x3130-upstream,id=sw1,bus=root_port13,multifunction=on \
 -device e1000,bus=root_port13,addr=0.1 \
 -device xio3130-downstream,id=fun1,bus=sw1,chassis=0,slot=3\
 -device e1000,bus=fun1


Error message on failure to probe my switch integrated e1000 (who doesn't have one of
those - lets pretend it's a more common switch PMU function or something like
that) is :
 e1000 0000:02:00.1: can't ioremap BAR 0: [??? 0x00000000 flags 0x0]

With this patch reverted it works as normal and the e1000 driver comes up.

Possibly useful stuff follows:

# lspci -tv
-[0000:00]-+-00.0  Red Hat, Inc. QEMU PCIe Host bridge
           +-01.0-[01]--
           +-02.0  Red Hat, Inc. Virtio block device
           +-03.0  Red Hat, Inc. Virtio network device
           \-04.0-[02-04]--+-00.0-[03-04]----00.0-[04]----00.0  Intel Corporation 82540EM Gigabit Ethernet Controller
                           \-00.1  Intel Corporation 82540EM Gigabit Ethernet Controller

with patch in place.
//without patch
Note I aligned by hand so may be errorr.

# dmesg | grep pci                                  
pci_bus 0000:00: root bus resource [mem 0x10000000-0x3efeffff window]
pci_bus 0000:00: root bus resource [io  0x0000-0xffff window]
pci_bus 0000:00: root bus resource [mem 0x8000000000-0xffffffffff window]
pci_bus 0000:00: root bus resource [bus 00-ff]
pci 0000:00:00.0: [1b36:0008] type 00 class 0x060000
pci 0000:00:01.0: [1b36:000c] type 01 class 0x060400
pci 0000:00:01.0: reg 0x10: [mem 0x10643000-0x10643fff]
pci 0000:00:02.0: [1af4:1001] type 00 class 0x010000
pci 0000:00:02.0: reg 0x10: [io  0x2200-0x227f]
pci 0000:00:02.0: reg 0x14: [mem 0x10642000-0x10642fff]
pci 0000:00:02.0: reg 0x20: [mem 0x8000000000-0x8000003fff 64bit pref]
pci 0000:00:03.0: [1af4:1000] type 00 class 0x020000
pci 0000:00:03.0: reg 0x10: [io  0x2280-0x229f]
pci 0000:00:03.0: reg 0x14: [mem 0x10641000-0x10641fff]
pci 0000:00:03.0: reg 0x20: [mem 0x8000004000-0x8000007fff 64bit pref]
pci 0000:00:03.0: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
pci 0000:00:04.0: [1b36:000c] type 01 class 0x060400
pci 0000:00:04.0: reg 0x10: [mem 0x10640000-0x10640fff]
pci 0000:02:00.0: [104c:8232] type 01 class 0x060400
pci 0000:02:00.1: [8086:100e] type 00 class 0x020000
pci 0000:02:00.1: reg 0x10: [mem 0x10200000-0x1021ffff]
pci 0000:02:00.1: reg 0x14: [io  0x1000-0x103f]
pci 0000:02:00.1: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
pci 0000:03:00.0: [104c:8233] type 01 class 0x060400
pci 0000:04:00.0: [8086:100e] type 00 class 0x020000
pci 0000:04:00.0: reg 0x10: [mem 0x10000000-0x1001ffff]
pci 0000:04:00.0: reg 0x14: [io  0x0000-0x003f]
pci 0000:04:00.0: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
pci 0000:00:01.0: bridge window [io  0x1000-0x0fff] to [bus 01] add_size 1000
pci 0000:00:01.0: bridge window [mem 0x00100000-0x000fffff 64bit pref] to [bus 01] add_size 200000 add_align 100000
pci 0000:00:01.0: bridge window [mem 0x00100000-0x000fffff] to [bus 01] add_size 200000 add_align 100000
pci 0000:03:00.0: bridge window [mem 0x00100000-0x000fffff 64bit pref] to [bus 04] add_size 200000 add_align 100000
pci 0000:03:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 04] add_size 100000 add_align 100000
pci 0000:02:00.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 03-04] add_size 200000 add_align 100000
pci 0000:02:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 03-04] add_size 100000 add_align 100000
pci 0000:00:04.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 02-04] add_size 300000 add_align 100000
pci 0000:00:04.0: bridge window [mem 0x00100000-0x002fffff] to [bus 02-04] add_size 100000 add_align 100000
pci 0000:00:01.0: BAR 14: assigned [mem 0x10000000-0x101fffff]
pci 0000:00:01.0: BAR 15: assigned [mem 0x8000000000-0x80001fffff 64bit pref]
pci 0000:00:04.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
// pci 0000:00:04.0: BAR 14: assigned [mem 0x10200000-0x104fffff]
pci 0000:00:04.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
// pci 0000:00:04.0: BAR 15: assigned [mem 0x8000200000-0x80005fffff 64bit pref]
pci 0000:00:03.0: BAR 6: assigned [mem 0x10400000-0x1043ffff pref]
// pci 0000:00:03.0: BAR 6: assigned [mem 0x10500000-0x1053ffff pref]
pci 0000:00:02.0: BAR 4: assigned [mem 0x8000300000-0x8000303fff 64bit pref]
//  pci 0000:00:02.0: BAR 4: assigned [mem 0x8000600000-0x8000603fff 64bit pref]
pci 0000:00:03.0: BAR 4: assigned [mem 0x8000304000-0x8000307fff 64bit pref]
//  pci 0000:00:03.0: BAR 4: assigned [mem 0x8000604000-0x8000607fff 64bit pref]
pci 0000:00:01.0: BAR 0: assigned [mem 0x10440000-0x10440fff]
//  pci 0000:00:01.0: BAR 0: assigned [mem 0x10540000-0x10540fff]
pci 0000:00:01.0: BAR 13: assigned [io  0x1000-0x1fff]
pci 0000:00:02.0: BAR 1: assigned [mem 0x10441000-0x10441fff]
//  pci 0000:00:02.0: BAR 1: assigned [mem 0x10541000-0x10541fff]
pci 0000:00:03.0: BAR 1: assigned [mem 0x10442000-0x10442fff]
// pci 0000:00:03.0: BAR 1: assigned [mem 0x10542000-0x10542fff]
pci 0000:00:04.0: BAR 0: assigned [mem 0x10443000-0x10443fff]
// pci 0000:00:01.0: BAR 0: assigned [mem 0x10540000-0x10540fff]
pci 0000:00:04.0: BAR 13: assigned [io  0x2000-0x3fff]
pci 0000:00:02.0: BAR 0: assigned [io  0x4000-0x407f]
pci 0000:00:03.0: BAR 0: assigned [io  0x4080-0x409f]
pci 0000:00:01.0: PCI bridge to [bus 01]
pci 0000:00:01.0:   bridge window [io  0x1000-0x1fff]
pci 0000:00:01.0:   bridge window [mem 0x10000000-0x101fffff]
pci 0000:00:01.0:   bridge window [mem 0x8000000000-0x80001fffff 64bit pref]
pci 0000:02:00.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
pci 0000:02:00.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
// pci 0000:02:00.0: BAR 15: assigned [mem 0x8000200000-0x80004fffff 64bit pref]
pci 0000:02:00.1: BAR 6: no space for [mem size 0x00040000 pref]
pci 0000:02:00.1: BAR 6: failed to assign [mem size 0x00040000 pref]
// pci 0000:02:00.1: BAR 6: assigned [mem 0x10400000-0x1043ffff pref]
pci 0000:02:00.1: BAR 0: failed to assign [mem size 0x00020000]
// pci 0000:02:00.1: BAR 0: assigned [mem 0x10440000-0x1045ffff]
pci 0000:02:00.0: BAR 13: assigned [io  0x2000-0x3fff]
pci 0000:02:00.1: BAR 1: no space for [io  size 0x0040]
// pci 0000:02:00.1: BAR 1: assigned [io  0x3000-0x303f]
pci 0000:02:00.1: BAR 1: failed to assign [io  size 0x0040]
pci 0000:03:00.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
pci 0000:03:00.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
// pci 0000:03:00.0: BAR 15: assigned [mem 0x8000200000-0x80003fffff 64bit pref]
pci 0000:03:00.0: BAR 13: assigned [io  0x2000-0x3fff]
// pci 0000:03:00.0: BAR 13: assigned [io  0x2000-0x2fff]
pci 0000:04:00.0: BAR 6: assigned [mem 0x10200000-0x1023ffff pref]
pci 0000:04:00.0: BAR 0: assigned [mem 0x10240000-0x1025ffff]
pci 0000:04:00.0: BAR 1: assigned [io  0x2000-0x203f]
pci 0000:03:00.0: PCI bridge to [bus 04]
pci 0000:03:00.0:   bridge window [io  0x2000-0x3fff]
// pci 0000:03:00.0:   bridge window [io  0x2000-0x2fff]
pci 0000:03:00.0:   bridge window [mem 0x10200000-0x103fffff]
pci 0000:03:00.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
// pci 0000:03:00.0:   bridge window [mem 0x8000200000-0x80003fffff 64bit pref]
pci 0000:02:00.0: PCI bridge to [bus 03-04]
pci 0000:02:00.0:   bridge window [io  0x2000-0x3fff]
// pci 0000:02:00.0:   bridge window [io  0x2000-0x2fff]
pci 0000:02:00.0:   bridge window [mem 0x10200000-0x103fffff]
pci 0000:02:00.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
// pci 0000:02:00.0:   bridge window [mem 0x8000200000-0x80004fffff 64bit pref]
pci 0000:00:04.0: PCI bridge to [bus 02-04]
pci 0000:00:04.0:   bridge window [io  0x2000-0x3fff]
pci 0000:00:04.0:   bridge window [mem 0x10200000-0x103fffff]
// pci 0000:00:04.0:   bridge window [mem 0x10200000-0x104fffff]
pci 0000:00:04.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
// pci 0000:00:04.0:   bridge window [mem 0x8000200000-0x80005fffff 64bit pref]
pci_bus 0000:00: Some PCI device resources are unassigned, try booting with pci=realloc
// LINE NOT PRESENT
pci_bus 0000:00: resource 4 [mem 0x10000000-0x3efeffff window]
pci_bus 0000:00: resource 5 [io  0x0000-0xffff window]
pci_bus 0000:00: resource 6 [mem 0x8000000000-0xffffffffff window]
pci_bus 0000:01: resource 0 [io  0x1000-0x1fff]
pci_bus 0000:01: resource 1 [mem 0x10000000-0x101fffff]
pci_bus 0000:01: resource 2 [mem 0x8000000000-0x80001fffff 64bit pref]
pci_bus 0000:02: resource 0 [io  0x2000-0x3fff]
pci_bus 0000:02: resource 1 [mem 0x10200000-0x103fffff]
// pci_bus 0000:02: resource 1 [mem 0x10200000-0x104fffff]
pci_bus 0000:02: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
//  pci_bus 0000:02: resource 2 [mem 0x8000200000-0x80005fffff 64bit pref]
pci_bus 0000:03: resource 0 [io  0x2000-0x3fff]
// pci_bus 0000:03: resource 0 [io  0x2000-0x2fff]
pci_bus 0000:03: resource 1 [mem 0x10200000-0x103fffff]
pci_bus 0000:03: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
// pci_bus 0000:03: resource 2 [mem 0x8000200000-0x80004fffff 64bit pref]
pci_bus 0000:04: resource 0 [io  0x2000-0x3fff]
// pci_bus 0000:04: resource 0 [io  0x2000-0x2fff]
pci_bus 0000:04: resource 1 [mem 0x10200000-0x103fffff]
// pci_bus 0000:04: resource 1 [mem 0x10200000-0x103fffff]
pci_bus 0000:04: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
// pci_bus 0000:04: resource 2 [mem 0x8000200000-0x80003fffff 64bit pref]
pcieport 0000:00:01.0: PME: Signaling with IRQ 51
pcieport 0000:00:01.0: AER: enabled with IRQ 51
pcieport 0000:00:01.0: pciehp: Slot #0 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep+
pcieport 0000:00:04.0: PME: Signaling with IRQ 52
pcieport 0000:00:04.0: AER: enabled with IRQ 52
pcieport 0000:00:04.0: pciehp: Slot #2 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep+
pcieport 0000:03:00.0: pciehp: Slot #3 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep-
virtio-pci 0000:00:02.0: enabling device (0000 -> 0003)
virtio-pci 0000:00:03.0: enabling device (0000 -> 0003)

All suggestions of things to test and other useful info to provide welcome.

>  drivers/pci/setup-bus.c | 62 ++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 61 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index 3b981da0fb4e..df9fc974b313 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -1768,7 +1768,10 @@ static void adjust_bridge_window(struct pci_dev *bridge, struct resource *res,
>  	}
>  
>  	res->end = res->start + new_size - 1;
> -	remove_from_list(add_list, res);
> +
> +	/* If the resource is part of the add_list remove it now */
> +	if (add_list)
> +		remove_from_list(add_list, res);
>  }
>  
>  static void pci_bus_distribute_available_resources(struct pci_bus *bus,
> @@ -1923,6 +1926,8 @@ static void pci_bridge_distribute_available_resources(struct pci_dev *bridge,
>  	if (!bridge->is_hotplug_bridge)
>  		return;
>  
> +	pci_dbg(bridge, "distributing available resources\n");
> +
>  	/* Take the initial extra resources from the hotplug port */
>  	available_io = bridge->resource[PCI_BRIDGE_IO_WINDOW];
>  	available_mmio = bridge->resource[PCI_BRIDGE_MEM_WINDOW];
> @@ -1934,6 +1939,59 @@ static void pci_bridge_distribute_available_resources(struct pci_dev *bridge,
>  					       available_mmio_pref);
>  }
>  
> +static bool pci_bridge_resources_not_assigned(struct pci_dev *dev)
> +{
> +	const struct resource *r;
> +
> +	/*
> +	 * Check the child device's resources and if they are not yet
> +	 * assigned it means we are configuring them (not the boot
> +	 * firmware) so we should be able to extend the upstream
> +	 * bridge's (that's the hotplug downstream PCIe port) resources
> +	 * in the same way we do with the normal hotplug case.
> +	 */
> +	r = &dev->resource[PCI_BRIDGE_IO_WINDOW];
> +	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
> +		return false;
> +	r = &dev->resource[PCI_BRIDGE_MEM_WINDOW];
> +	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
> +		return false;
> +	r = &dev->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
> +	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
> +		return false;
> +
> +	return true;
> +}
> +
> +static void pci_root_bus_distribute_available_resources(struct pci_bus *bus,
> +							struct list_head *add_list)
> +{
> +	struct pci_dev *dev, *bridge = bus->self;
> +
> +	for_each_pci_bridge(dev, bus) {
> +		struct pci_bus *b;
> +
> +		b = dev->subordinate;
> +		if (!b)
> +			continue;
> +
> +		/*
> +		 * Need to check "bridge" here too because it is NULL
> +		 * in case of root bus.
> +		 */
> +		if (bridge && pci_bridge_resources_not_assigned(dev)) {
> +			pci_bridge_distribute_available_resources(bridge, add_list);
> +			/*
> +			 * There is only PCIe upstream port on the bus
> +			 * so we don't need to go futher.
> +			 */
> +			return;
> +		}
> +
> +		pci_root_bus_distribute_available_resources(b, add_list);
> +	}
> +}
> +
>  /*
>   * First try will not touch PCI bridge res.
>   * Second and later try will clear small leaf bridge res.
> @@ -1973,6 +2031,8 @@ void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus)
>  	 */
>  	__pci_bus_size_bridges(bus, add_list);
>  
> +	pci_root_bus_distribute_available_resources(bus, add_list);
> +
>  	/* Depth last, allocate resources and update the hardware. */
>  	__pci_bus_assign_resources(bus, add_list, &fail_head);
>  	if (add_list)

Re: Regression: Re: [PATCH v2 4/6] PCI: Distribute available resources for root buses too

[Mika Westerberg]

Hi,

On Fri, Oct 14, 2022 at 12:45:53PM +0100, Jonathan Cameron wrote:
> On Mon,  5 Sep 2022 11:02:30 +0300
> Mika Westerberg <mika.westerberg@linux.intel.com> wrote:
> 
> > Currently we distribute the spare resources only upon hot-add so if
> > there are PCI devices connected already when the initial root bus scan
> > is done, and they have not been fully configured by the BIOS, we may end
> > up allocating resources just enough to cover only what is currently
> > there. If some of those devices are hotplug bridges themselves we do not
> > leave any additional resource space for future expansion.
> > 
> > For this reason distribute the available resources for root buses too to
> > make this work the same way we do in the normal hotplug case.
> > 
> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=216000
> > Reported-by: Chris Chiu <chris.chiu@canonical.com>
> > Tested-by: Chris Chiu <chris.chiu@canonical.com>
> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > ---
> 
> Early days, but I have a regression that's bisecting to this patch
> after I did an optimistic checkout of mainline mid merge window.
> 
> Initial platform was QEMU emulation of CXL on arm64 with EDK2 / ACPI etc.
> That uses an extended version of the PCI eXpander Bus (PXB) with extended
> version of the emulated pci root ports.  Particular test was
> 
> 1 PXB, 2 RP, below first RP switch USP, with two functions (USP and
> a stand along switch CCI), below that 4 DSP each with a CXL type 3 device.
> 
> Clearly something wrong with the error handling in CXL code as it goes boom
> spectacularly.  I'll address that separately.  Anyhow, setup way to complex
> to debug easily. 
> 
> Anyhow to make this easier for others to poke I set up equivalent with pxb-pcie
> etc and it happens there.  Everything works with the exception of additional
> functions on USP.
> 
> Next up in minimal test case (could be more minimal but I'm lazy) is 
> 
> ../qemu/bin/native/aarch64-softmmu/qemu-system-aarch64 -M virt,nvdimm=on,gic-version=3,cxl=on -m 4g,maxmem=8G,slots=8 -cpu max -smp 4 \
>  -kernel Image \
>  -drive if=none,file=full.qcow2,format=qcow2,id=hd \
>  -device pcie-root-port,id=root_port1 -device virtio-blk-pci,drive=hd \
>  -netdev type=user,id=mynet,hostfwd=tcp::5555-:22 \
>  -device virtio-net-pci,netdev=mynet,id=bob \
>  -nographic -no-reboot -append 'earlycon root=/dev/vda2 fsck.mode=skip tp_printk maxcpus=4' \
>  -monitor telnet:127.0.0.1:1235,server,nowait -bios QEMU_EFI.fd \
>  -object memory-backend-ram,size=4G,id=mem0 \
>  -numa node,nodeid=0,cpus=0-3,memdev=mem0 \
> # Interesting part follows:
>  -device pcie-root-port,port=0,id=root_port13,chassis=0,slot=2 \
>  -device x3130-upstream,id=sw1,bus=root_port13,multifunction=on \
>  -device e1000,bus=root_port13,addr=0.1 \
>  -device xio3130-downstream,id=fun1,bus=sw1,chassis=0,slot=3\
>  -device e1000,bus=fun1
> 
> 
> Error message on failure to probe my switch integrated e1000 (who doesn't have one of
> those - lets pretend it's a more common switch PMU function or something like
> that) is :
>  e1000 0000:02:00.1: can't ioremap BAR 0: [??? 0x00000000 flags 0x0]
> 
> With this patch reverted it works as normal and the e1000 driver comes up.
> 
> Possibly useful stuff follows:
> 
> # lspci -tv
> -[0000:00]-+-00.0  Red Hat, Inc. QEMU PCIe Host bridge
>            +-01.0-[01]--
>            +-02.0  Red Hat, Inc. Virtio block device
>            +-03.0  Red Hat, Inc. Virtio network device
>            \-04.0-[02-04]--+-00.0-[03-04]----00.0-[04]----00.0  Intel Corporation 82540EM Gigabit Ethernet Controller
>                            \-00.1  Intel Corporation 82540EM Gigabit Ethernet Controller
> 
> with patch in place.
> //without patch
> Note I aligned by hand so may be errorr.
> 
> # dmesg | grep pci                                  
> pci_bus 0000:00: root bus resource [mem 0x10000000-0x3efeffff window]
> pci_bus 0000:00: root bus resource [io  0x0000-0xffff window]
> pci_bus 0000:00: root bus resource [mem 0x8000000000-0xffffffffff window]
> pci_bus 0000:00: root bus resource [bus 00-ff]
> pci 0000:00:00.0: [1b36:0008] type 00 class 0x060000
> pci 0000:00:01.0: [1b36:000c] type 01 class 0x060400
> pci 0000:00:01.0: reg 0x10: [mem 0x10643000-0x10643fff]
> pci 0000:00:02.0: [1af4:1001] type 00 class 0x010000
> pci 0000:00:02.0: reg 0x10: [io  0x2200-0x227f]
> pci 0000:00:02.0: reg 0x14: [mem 0x10642000-0x10642fff]
> pci 0000:00:02.0: reg 0x20: [mem 0x8000000000-0x8000003fff 64bit pref]
> pci 0000:00:03.0: [1af4:1000] type 00 class 0x020000
> pci 0000:00:03.0: reg 0x10: [io  0x2280-0x229f]
> pci 0000:00:03.0: reg 0x14: [mem 0x10641000-0x10641fff]
> pci 0000:00:03.0: reg 0x20: [mem 0x8000004000-0x8000007fff 64bit pref]
> pci 0000:00:03.0: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
> pci 0000:00:04.0: [1b36:000c] type 01 class 0x060400
> pci 0000:00:04.0: reg 0x10: [mem 0x10640000-0x10640fff]
> pci 0000:02:00.0: [104c:8232] type 01 class 0x060400
> pci 0000:02:00.1: [8086:100e] type 00 class 0x020000
> pci 0000:02:00.1: reg 0x10: [mem 0x10200000-0x1021ffff]
> pci 0000:02:00.1: reg 0x14: [io  0x1000-0x103f]
> pci 0000:02:00.1: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
> pci 0000:03:00.0: [104c:8233] type 01 class 0x060400
> pci 0000:04:00.0: [8086:100e] type 00 class 0x020000
> pci 0000:04:00.0: reg 0x10: [mem 0x10000000-0x1001ffff]
> pci 0000:04:00.0: reg 0x14: [io  0x0000-0x003f]
> pci 0000:04:00.0: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
> pci 0000:00:01.0: bridge window [io  0x1000-0x0fff] to [bus 01] add_size 1000
> pci 0000:00:01.0: bridge window [mem 0x00100000-0x000fffff 64bit pref] to [bus 01] add_size 200000 add_align 100000
> pci 0000:00:01.0: bridge window [mem 0x00100000-0x000fffff] to [bus 01] add_size 200000 add_align 100000
> pci 0000:03:00.0: bridge window [mem 0x00100000-0x000fffff 64bit pref] to [bus 04] add_size 200000 add_align 100000
> pci 0000:03:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 04] add_size 100000 add_align 100000
> pci 0000:02:00.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 03-04] add_size 200000 add_align 100000
> pci 0000:02:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 03-04] add_size 100000 add_align 100000
> pci 0000:00:04.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 02-04] add_size 300000 add_align 100000
> pci 0000:00:04.0: bridge window [mem 0x00100000-0x002fffff] to [bus 02-04] add_size 100000 add_align 100000
> pci 0000:00:01.0: BAR 14: assigned [mem 0x10000000-0x101fffff]
> pci 0000:00:01.0: BAR 15: assigned [mem 0x8000000000-0x80001fffff 64bit pref]
> pci 0000:00:04.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
> // pci 0000:00:04.0: BAR 14: assigned [mem 0x10200000-0x104fffff]
> pci 0000:00:04.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:00:04.0: BAR 15: assigned [mem 0x8000200000-0x80005fffff 64bit pref]
> pci 0000:00:03.0: BAR 6: assigned [mem 0x10400000-0x1043ffff pref]
> // pci 0000:00:03.0: BAR 6: assigned [mem 0x10500000-0x1053ffff pref]
> pci 0000:00:02.0: BAR 4: assigned [mem 0x8000300000-0x8000303fff 64bit pref]
> //  pci 0000:00:02.0: BAR 4: assigned [mem 0x8000600000-0x8000603fff 64bit pref]
> pci 0000:00:03.0: BAR 4: assigned [mem 0x8000304000-0x8000307fff 64bit pref]
> //  pci 0000:00:03.0: BAR 4: assigned [mem 0x8000604000-0x8000607fff 64bit pref]
> pci 0000:00:01.0: BAR 0: assigned [mem 0x10440000-0x10440fff]
> //  pci 0000:00:01.0: BAR 0: assigned [mem 0x10540000-0x10540fff]
> pci 0000:00:01.0: BAR 13: assigned [io  0x1000-0x1fff]
> pci 0000:00:02.0: BAR 1: assigned [mem 0x10441000-0x10441fff]
> //  pci 0000:00:02.0: BAR 1: assigned [mem 0x10541000-0x10541fff]
> pci 0000:00:03.0: BAR 1: assigned [mem 0x10442000-0x10442fff]
> // pci 0000:00:03.0: BAR 1: assigned [mem 0x10542000-0x10542fff]
> pci 0000:00:04.0: BAR 0: assigned [mem 0x10443000-0x10443fff]
> // pci 0000:00:01.0: BAR 0: assigned [mem 0x10540000-0x10540fff]
> pci 0000:00:04.0: BAR 13: assigned [io  0x2000-0x3fff]
> pci 0000:00:02.0: BAR 0: assigned [io  0x4000-0x407f]
> pci 0000:00:03.0: BAR 0: assigned [io  0x4080-0x409f]
> pci 0000:00:01.0: PCI bridge to [bus 01]
> pci 0000:00:01.0:   bridge window [io  0x1000-0x1fff]
> pci 0000:00:01.0:   bridge window [mem 0x10000000-0x101fffff]
> pci 0000:00:01.0:   bridge window [mem 0x8000000000-0x80001fffff 64bit pref]
> pci 0000:02:00.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
> pci 0000:02:00.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:02:00.0: BAR 15: assigned [mem 0x8000200000-0x80004fffff 64bit pref]
> pci 0000:02:00.1: BAR 6: no space for [mem size 0x00040000 pref]
> pci 0000:02:00.1: BAR 6: failed to assign [mem size 0x00040000 pref]
> // pci 0000:02:00.1: BAR 6: assigned [mem 0x10400000-0x1043ffff pref]
> pci 0000:02:00.1: BAR 0: failed to assign [mem size 0x00020000]
> // pci 0000:02:00.1: BAR 0: assigned [mem 0x10440000-0x1045ffff]
> pci 0000:02:00.0: BAR 13: assigned [io  0x2000-0x3fff]
> pci 0000:02:00.1: BAR 1: no space for [io  size 0x0040]
> // pci 0000:02:00.1: BAR 1: assigned [io  0x3000-0x303f]
> pci 0000:02:00.1: BAR 1: failed to assign [io  size 0x0040]
> pci 0000:03:00.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
> pci 0000:03:00.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:03:00.0: BAR 15: assigned [mem 0x8000200000-0x80003fffff 64bit pref]
> pci 0000:03:00.0: BAR 13: assigned [io  0x2000-0x3fff]
> // pci 0000:03:00.0: BAR 13: assigned [io  0x2000-0x2fff]
> pci 0000:04:00.0: BAR 6: assigned [mem 0x10200000-0x1023ffff pref]
> pci 0000:04:00.0: BAR 0: assigned [mem 0x10240000-0x1025ffff]
> pci 0000:04:00.0: BAR 1: assigned [io  0x2000-0x203f]
> pci 0000:03:00.0: PCI bridge to [bus 04]
> pci 0000:03:00.0:   bridge window [io  0x2000-0x3fff]
> // pci 0000:03:00.0:   bridge window [io  0x2000-0x2fff]
> pci 0000:03:00.0:   bridge window [mem 0x10200000-0x103fffff]
> pci 0000:03:00.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:03:00.0:   bridge window [mem 0x8000200000-0x80003fffff 64bit pref]
> pci 0000:02:00.0: PCI bridge to [bus 03-04]
> pci 0000:02:00.0:   bridge window [io  0x2000-0x3fff]
> // pci 0000:02:00.0:   bridge window [io  0x2000-0x2fff]
> pci 0000:02:00.0:   bridge window [mem 0x10200000-0x103fffff]
> pci 0000:02:00.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:02:00.0:   bridge window [mem 0x8000200000-0x80004fffff 64bit pref]
> pci 0000:00:04.0: PCI bridge to [bus 02-04]
> pci 0000:00:04.0:   bridge window [io  0x2000-0x3fff]
> pci 0000:00:04.0:   bridge window [mem 0x10200000-0x103fffff]
> // pci 0000:00:04.0:   bridge window [mem 0x10200000-0x104fffff]
> pci 0000:00:04.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:00:04.0:   bridge window [mem 0x8000200000-0x80005fffff 64bit pref]
> pci_bus 0000:00: Some PCI device resources are unassigned, try booting with pci=realloc
> // LINE NOT PRESENT
> pci_bus 0000:00: resource 4 [mem 0x10000000-0x3efeffff window]
> pci_bus 0000:00: resource 5 [io  0x0000-0xffff window]
> pci_bus 0000:00: resource 6 [mem 0x8000000000-0xffffffffff window]
> pci_bus 0000:01: resource 0 [io  0x1000-0x1fff]
> pci_bus 0000:01: resource 1 [mem 0x10000000-0x101fffff]
> pci_bus 0000:01: resource 2 [mem 0x8000000000-0x80001fffff 64bit pref]
> pci_bus 0000:02: resource 0 [io  0x2000-0x3fff]
> pci_bus 0000:02: resource 1 [mem 0x10200000-0x103fffff]
> // pci_bus 0000:02: resource 1 [mem 0x10200000-0x104fffff]
> pci_bus 0000:02: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
> //  pci_bus 0000:02: resource 2 [mem 0x8000200000-0x80005fffff 64bit pref]
> pci_bus 0000:03: resource 0 [io  0x2000-0x3fff]
> // pci_bus 0000:03: resource 0 [io  0x2000-0x2fff]
> pci_bus 0000:03: resource 1 [mem 0x10200000-0x103fffff]
> pci_bus 0000:03: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci_bus 0000:03: resource 2 [mem 0x8000200000-0x80004fffff 64bit pref]
> pci_bus 0000:04: resource 0 [io  0x2000-0x3fff]
> // pci_bus 0000:04: resource 0 [io  0x2000-0x2fff]
> pci_bus 0000:04: resource 1 [mem 0x10200000-0x103fffff]
> // pci_bus 0000:04: resource 1 [mem 0x10200000-0x103fffff]
> pci_bus 0000:04: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci_bus 0000:04: resource 2 [mem 0x8000200000-0x80003fffff 64bit pref]
> pcieport 0000:00:01.0: PME: Signaling with IRQ 51
> pcieport 0000:00:01.0: AER: enabled with IRQ 51
> pcieport 0000:00:01.0: pciehp: Slot #0 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep+
> pcieport 0000:00:04.0: PME: Signaling with IRQ 52
> pcieport 0000:00:04.0: AER: enabled with IRQ 52
> pcieport 0000:00:04.0: pciehp: Slot #2 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep+
> pcieport 0000:03:00.0: pciehp: Slot #3 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep-
> virtio-pci 0000:00:02.0: enabling device (0000 -> 0003)
> virtio-pci 0000:00:03.0: enabling device (0000 -> 0003)
> 
> All suggestions of things to test and other useful info to provide welcome.

Thanks for the detailed report! I wonder if you could try the below
patch and see if it changes anything? I will be on vacation starting
tomorrow for the whole next week so if nothing else helps then I suppose
we should revert that commit for now.

I can look at this further after I come back.

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index dc6a30ee6edf..637f1a1df409 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1939,7 +1939,7 @@ static void pci_bridge_distribute_available_resources(struct pci_dev *bridge,
 					       available_mmio_pref);
 }
 
-static bool pci_bridge_resources_not_assigned(struct pci_dev *dev)
+static bool pci_bridge_resources_assigned(struct pci_dev *dev)
 {
 	const struct resource *r;
 
@@ -1951,16 +1951,19 @@ static bool pci_bridge_resources_not_assigned(struct pci_dev *dev)
 	 * in the same way we do with the normal hotplug case.
 	 */
 	r = &dev->resource[PCI_BRIDGE_IO_WINDOW];
-	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
-		return false;
+	dev_info(dev->dev, "check %pR\n", r);
+	if (r->flags && !(r->flags & IORESOURCE_STARTALIGN))
+		return true;
 	r = &dev->resource[PCI_BRIDGE_MEM_WINDOW];
-	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
-		return false;
+	dev_info(dev->dev, "check %pR\n", r);
+	if (r->flags && !(r->flags & IORESOURCE_STARTALIGN))
+		return true;
 	r = &dev->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
-	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
-		return false;
+	dev_info(dev->dev, "check %pR\n", r);
+	if (r->flags && !(r->flags & IORESOURCE_STARTALIGN))
+		return true;
 
-	return true;
+	return false;
 }
 
 static void pci_root_bus_distribute_available_resources(struct pci_bus *bus,
@@ -1979,7 +1982,7 @@ static void pci_root_bus_distribute_available_resources(struct pci_bus *bus,
 		 * Need to check "bridge" here too because it is NULL
 		 * in case of root bus.
 		 */
-		if (bridge && pci_bridge_resources_not_assigned(dev)) {
+		if (bridge && !pci_bridge_resources_assigned(dev)) {
 			pci_bridge_distribute_available_resources(bridge, add_list);
 			/*
 			 * There is only PCIe upstream port on the bus

Re: Regression: Re: [PATCH v2 4/6] PCI: Distribute available resources for root buses too

[Jonathan Cameron]

On Fri, 14 Oct 2022 16:30:34 +0300
Mika Westerberg <mika.westerberg@linux.intel.com> wrote:

> Hi,
> 
> On Fri, Oct 14, 2022 at 12:45:53PM +0100, Jonathan Cameron wrote:
> > On Mon,  5 Sep 2022 11:02:30 +0300
> > Mika Westerberg <mika.westerberg@linux.intel.com> wrote:
> >   
> > > Currently we distribute the spare resources only upon hot-add so if
> > > there are PCI devices connected already when the initial root bus scan
> > > is done, and they have not been fully configured by the BIOS, we may end
> > > up allocating resources just enough to cover only what is currently
> > > there. If some of those devices are hotplug bridges themselves we do not
> > > leave any additional resource space for future expansion.
> > > 
> > > For this reason distribute the available resources for root buses too to
> > > make this work the same way we do in the normal hotplug case.
> > > 
> > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=216000
> > > Reported-by: Chris Chiu <chris.chiu@canonical.com>
> > > Tested-by: Chris Chiu <chris.chiu@canonical.com>
> > > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > ---  
> > 
> > Early days, but I have a regression that's bisecting to this patch
> > after I did an optimistic checkout of mainline mid merge window.
> > 
> > Initial platform was QEMU emulation of CXL on arm64 with EDK2 / ACPI etc.
> > That uses an extended version of the PCI eXpander Bus (PXB) with extended
> > version of the emulated pci root ports.  Particular test was
> > 
> > 1 PXB, 2 RP, below first RP switch USP, with two functions (USP and
> > a stand along switch CCI), below that 4 DSP each with a CXL type 3 device.
> > 
> > Clearly something wrong with the error handling in CXL code as it goes boom
> > spectacularly.  I'll address that separately.  Anyhow, setup way to complex
> > to debug easily. 
> > 
> > Anyhow to make this easier for others to poke I set up equivalent with pxb-pcie
> > etc and it happens there.  Everything works with the exception of additional
> > functions on USP.
> > 
> > Next up in minimal test case (could be more minimal but I'm lazy) is 
> > 
> > ../qemu/bin/native/aarch64-softmmu/qemu-system-aarch64 -M virt,nvdimm=on,gic-version=3,cxl=on -m 4g,maxmem=8G,slots=8 -cpu max -smp 4 \
> >  -kernel Image \
> >  -drive if=none,file=full.qcow2,format=qcow2,id=hd \
> >  -device pcie-root-port,id=root_port1 -device virtio-blk-pci,drive=hd \
> >  -netdev type=user,id=mynet,hostfwd=tcp::5555-:22 \
> >  -device virtio-net-pci,netdev=mynet,id=bob \
> >  -nographic -no-reboot -append 'earlycon root=/dev/vda2 fsck.mode=skip tp_printk maxcpus=4' \
> >  -monitor telnet:127.0.0.1:1235,server,nowait -bios QEMU_EFI.fd \
> >  -object memory-backend-ram,size=4G,id=mem0 \
> >  -numa node,nodeid=0,cpus=0-3,memdev=mem0 \
> > # Interesting part follows:
> >  -device pcie-root-port,port=0,id=root_port13,chassis=0,slot=2 \
> >  -device x3130-upstream,id=sw1,bus=root_port13,multifunction=on \
> >  -device e1000,bus=root_port13,addr=0.1 \
> >  -device xio3130-downstream,id=fun1,bus=sw1,chassis=0,slot=3\
> >  -device e1000,bus=fun1
> > 
> > 
> > Error message on failure to probe my switch integrated e1000 (who doesn't have one of
> > those - lets pretend it's a more common switch PMU function or something like
> > that) is :
> >  e1000 0000:02:00.1: can't ioremap BAR 0: [??? 0x00000000 flags 0x0]
> > 
> > With this patch reverted it works as normal and the e1000 driver comes up.
> > 
> > Possibly useful stuff follows:
> > 
> > # lspci -tv
> > -[0000:00]-+-00.0  Red Hat, Inc. QEMU PCIe Host bridge
> >            +-01.0-[01]--
> >            +-02.0  Red Hat, Inc. Virtio block device
> >            +-03.0  Red Hat, Inc. Virtio network device
> >            \-04.0-[02-04]--+-00.0-[03-04]----00.0-[04]----00.0  Intel Corporation 82540EM Gigabit Ethernet Controller
> >                            \-00.1  Intel Corporation 82540EM Gigabit Ethernet Controller
> > 
> > with patch in place.
> > //without patch
> > Note I aligned by hand so may be errorr.
> > 
> > # dmesg | grep pci                                  
> > pci_bus 0000:00: root bus resource [mem 0x10000000-0x3efeffff window]
> > pci_bus 0000:00: root bus resource [io  0x0000-0xffff window]
> > pci_bus 0000:00: root bus resource [mem 0x8000000000-0xffffffffff window]
> > pci_bus 0000:00: root bus resource [bus 00-ff]
> > pci 0000:00:00.0: [1b36:0008] type 00 class 0x060000
> > pci 0000:00:01.0: [1b36:000c] type 01 class 0x060400
> > pci 0000:00:01.0: reg 0x10: [mem 0x10643000-0x10643fff]
> > pci 0000:00:02.0: [1af4:1001] type 00 class 0x010000
> > pci 0000:00:02.0: reg 0x10: [io  0x2200-0x227f]
> > pci 0000:00:02.0: reg 0x14: [mem 0x10642000-0x10642fff]
> > pci 0000:00:02.0: reg 0x20: [mem 0x8000000000-0x8000003fff 64bit pref]
> > pci 0000:00:03.0: [1af4:1000] type 00 class 0x020000
> > pci 0000:00:03.0: reg 0x10: [io  0x2280-0x229f]
> > pci 0000:00:03.0: reg 0x14: [mem 0x10641000-0x10641fff]
> > pci 0000:00:03.0: reg 0x20: [mem 0x8000004000-0x8000007fff 64bit pref]
> > pci 0000:00:03.0: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
> > pci 0000:00:04.0: [1b36:000c] type 01 class 0x060400
> > pci 0000:00:04.0: reg 0x10: [mem 0x10640000-0x10640fff]
> > pci 0000:02:00.0: [104c:8232] type 01 class 0x060400
> > pci 0000:02:00.1: [8086:100e] type 00 class 0x020000
> > pci 0000:02:00.1: reg 0x10: [mem 0x10200000-0x1021ffff]
> > pci 0000:02:00.1: reg 0x14: [io  0x1000-0x103f]
> > pci 0000:02:00.1: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
> > pci 0000:03:00.0: [104c:8233] type 01 class 0x060400
> > pci 0000:04:00.0: [8086:100e] type 00 class 0x020000
> > pci 0000:04:00.0: reg 0x10: [mem 0x10000000-0x1001ffff]
> > pci 0000:04:00.0: reg 0x14: [io  0x0000-0x003f]
> > pci 0000:04:00.0: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
> > pci 0000:00:01.0: bridge window [io  0x1000-0x0fff] to [bus 01] add_size 1000
> > pci 0000:00:01.0: bridge window [mem 0x00100000-0x000fffff 64bit pref] to [bus 01] add_size 200000 add_align 100000
> > pci 0000:00:01.0: bridge window [mem 0x00100000-0x000fffff] to [bus 01] add_size 200000 add_align 100000
> > pci 0000:03:00.0: bridge window [mem 0x00100000-0x000fffff 64bit pref] to [bus 04] add_size 200000 add_align 100000
> > pci 0000:03:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 04] add_size 100000 add_align 100000
> > pci 0000:02:00.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 03-04] add_size 200000 add_align 100000
> > pci 0000:02:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 03-04] add_size 100000 add_align 100000
> > pci 0000:00:04.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 02-04] add_size 300000 add_align 100000
> > pci 0000:00:04.0: bridge window [mem 0x00100000-0x002fffff] to [bus 02-04] add_size 100000 add_align 100000
> > pci 0000:00:01.0: BAR 14: assigned [mem 0x10000000-0x101fffff]
> > pci 0000:00:01.0: BAR 15: assigned [mem 0x8000000000-0x80001fffff 64bit pref]
> > pci 0000:00:04.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
> > // pci 0000:00:04.0: BAR 14: assigned [mem 0x10200000-0x104fffff]
> > pci 0000:00:04.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
> > // pci 0000:00:04.0: BAR 15: assigned [mem 0x8000200000-0x80005fffff 64bit pref]
> > pci 0000:00:03.0: BAR 6: assigned [mem 0x10400000-0x1043ffff pref]
> > // pci 0000:00:03.0: BAR 6: assigned [mem 0x10500000-0x1053ffff pref]
> > pci 0000:00:02.0: BAR 4: assigned [mem 0x8000300000-0x8000303fff 64bit pref]
> > //  pci 0000:00:02.0: BAR 4: assigned [mem 0x8000600000-0x8000603fff 64bit pref]
> > pci 0000:00:03.0: BAR 4: assigned [mem 0x8000304000-0x8000307fff 64bit pref]
> > //  pci 0000:00:03.0: BAR 4: assigned [mem 0x8000604000-0x8000607fff 64bit pref]
> > pci 0000:00:01.0: BAR 0: assigned [mem 0x10440000-0x10440fff]
> > //  pci 0000:00:01.0: BAR 0: assigned [mem 0x10540000-0x10540fff]
> > pci 0000:00:01.0: BAR 13: assigned [io  0x1000-0x1fff]
> > pci 0000:00:02.0: BAR 1: assigned [mem 0x10441000-0x10441fff]
> > //  pci 0000:00:02.0: BAR 1: assigned [mem 0x10541000-0x10541fff]
> > pci 0000:00:03.0: BAR 1: assigned [mem 0x10442000-0x10442fff]
> > // pci 0000:00:03.0: BAR 1: assigned [mem 0x10542000-0x10542fff]
> > pci 0000:00:04.0: BAR 0: assigned [mem 0x10443000-0x10443fff]
> > // pci 0000:00:01.0: BAR 0: assigned [mem 0x10540000-0x10540fff]
> > pci 0000:00:04.0: BAR 13: assigned [io  0x2000-0x3fff]
> > pci 0000:00:02.0: BAR 0: assigned [io  0x4000-0x407f]
> > pci 0000:00:03.0: BAR 0: assigned [io  0x4080-0x409f]
> > pci 0000:00:01.0: PCI bridge to [bus 01]
> > pci 0000:00:01.0:   bridge window [io  0x1000-0x1fff]
> > pci 0000:00:01.0:   bridge window [mem 0x10000000-0x101fffff]
> > pci 0000:00:01.0:   bridge window [mem 0x8000000000-0x80001fffff 64bit pref]
> > pci 0000:02:00.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
> > pci 0000:02:00.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
> > // pci 0000:02:00.0: BAR 15: assigned [mem 0x8000200000-0x80004fffff 64bit pref]
> > pci 0000:02:00.1: BAR 6: no space for [mem size 0x00040000 pref]
> > pci 0000:02:00.1: BAR 6: failed to assign [mem size 0x00040000 pref]
> > // pci 0000:02:00.1: BAR 6: assigned [mem 0x10400000-0x1043ffff pref]
> > pci 0000:02:00.1: BAR 0: failed to assign [mem size 0x00020000]
> > // pci 0000:02:00.1: BAR 0: assigned [mem 0x10440000-0x1045ffff]
> > pci 0000:02:00.0: BAR 13: assigned [io  0x2000-0x3fff]
> > pci 0000:02:00.1: BAR 1: no space for [io  size 0x0040]
> > // pci 0000:02:00.1: BAR 1: assigned [io  0x3000-0x303f]
> > pci 0000:02:00.1: BAR 1: failed to assign [io  size 0x0040]
> > pci 0000:03:00.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
> > pci 0000:03:00.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
> > // pci 0000:03:00.0: BAR 15: assigned [mem 0x8000200000-0x80003fffff 64bit pref]
> > pci 0000:03:00.0: BAR 13: assigned [io  0x2000-0x3fff]
> > // pci 0000:03:00.0: BAR 13: assigned [io  0x2000-0x2fff]
> > pci 0000:04:00.0: BAR 6: assigned [mem 0x10200000-0x1023ffff pref]
> > pci 0000:04:00.0: BAR 0: assigned [mem 0x10240000-0x1025ffff]
> > pci 0000:04:00.0: BAR 1: assigned [io  0x2000-0x203f]
> > pci 0000:03:00.0: PCI bridge to [bus 04]
> > pci 0000:03:00.0:   bridge window [io  0x2000-0x3fff]
> > // pci 0000:03:00.0:   bridge window [io  0x2000-0x2fff]
> > pci 0000:03:00.0:   bridge window [mem 0x10200000-0x103fffff]
> > pci 0000:03:00.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
> > // pci 0000:03:00.0:   bridge window [mem 0x8000200000-0x80003fffff 64bit pref]
> > pci 0000:02:00.0: PCI bridge to [bus 03-04]
> > pci 0000:02:00.0:   bridge window [io  0x2000-0x3fff]
> > // pci 0000:02:00.0:   bridge window [io  0x2000-0x2fff]
> > pci 0000:02:00.0:   bridge window [mem 0x10200000-0x103fffff]
> > pci 0000:02:00.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
> > // pci 0000:02:00.0:   bridge window [mem 0x8000200000-0x80004fffff 64bit pref]
> > pci 0000:00:04.0: PCI bridge to [bus 02-04]
> > pci 0000:00:04.0:   bridge window [io  0x2000-0x3fff]
> > pci 0000:00:04.0:   bridge window [mem 0x10200000-0x103fffff]
> > // pci 0000:00:04.0:   bridge window [mem 0x10200000-0x104fffff]
> > pci 0000:00:04.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
> > // pci 0000:00:04.0:   bridge window [mem 0x8000200000-0x80005fffff 64bit pref]
> > pci_bus 0000:00: Some PCI device resources are unassigned, try booting with pci=realloc
> > // LINE NOT PRESENT
> > pci_bus 0000:00: resource 4 [mem 0x10000000-0x3efeffff window]
> > pci_bus 0000:00: resource 5 [io  0x0000-0xffff window]
> > pci_bus 0000:00: resource 6 [mem 0x8000000000-0xffffffffff window]
> > pci_bus 0000:01: resource 0 [io  0x1000-0x1fff]
> > pci_bus 0000:01: resource 1 [mem 0x10000000-0x101fffff]
> > pci_bus 0000:01: resource 2 [mem 0x8000000000-0x80001fffff 64bit pref]
> > pci_bus 0000:02: resource 0 [io  0x2000-0x3fff]
> > pci_bus 0000:02: resource 1 [mem 0x10200000-0x103fffff]
> > // pci_bus 0000:02: resource 1 [mem 0x10200000-0x104fffff]
> > pci_bus 0000:02: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
> > //  pci_bus 0000:02: resource 2 [mem 0x8000200000-0x80005fffff 64bit pref]
> > pci_bus 0000:03: resource 0 [io  0x2000-0x3fff]
> > // pci_bus 0000:03: resource 0 [io  0x2000-0x2fff]
> > pci_bus 0000:03: resource 1 [mem 0x10200000-0x103fffff]
> > pci_bus 0000:03: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
> > // pci_bus 0000:03: resource 2 [mem 0x8000200000-0x80004fffff 64bit pref]
> > pci_bus 0000:04: resource 0 [io  0x2000-0x3fff]
> > // pci_bus 0000:04: resource 0 [io  0x2000-0x2fff]
> > pci_bus 0000:04: resource 1 [mem 0x10200000-0x103fffff]
> > // pci_bus 0000:04: resource 1 [mem 0x10200000-0x103fffff]
> > pci_bus 0000:04: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
> > // pci_bus 0000:04: resource 2 [mem 0x8000200000-0x80003fffff 64bit pref]
> > pcieport 0000:00:01.0: PME: Signaling with IRQ 51
> > pcieport 0000:00:01.0: AER: enabled with IRQ 51
> > pcieport 0000:00:01.0: pciehp: Slot #0 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep+
> > pcieport 0000:00:04.0: PME: Signaling with IRQ 52
> > pcieport 0000:00:04.0: AER: enabled with IRQ 52
> > pcieport 0000:00:04.0: pciehp: Slot #2 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep+
> > pcieport 0000:03:00.0: pciehp: Slot #3 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep-
> > virtio-pci 0000:00:02.0: enabling device (0000 -> 0003)
> > virtio-pci 0000:00:03.0: enabling device (0000 -> 0003)
> > 
> > All suggestions of things to test and other useful info to provide welcome.  
> 
> Thanks for the detailed report! I wonder if you could try the below
> patch and see if it changes anything?
Thanks for the quick response.

Doesn't fix it unfortunately.

For reference with the extra prints and a bit of context (trivial fix below)

pci 0000:0e:00.0: bridge window [mem 0x00100000-0x000fffff 64bit pref] to [bus 0f] add_size 200000 add_align 100000
pci 0000:0e:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 0f] add_size 100000 add_align 100000
pci 0000:0d:00.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 0e-0f] add_size 200000 add_align 100000
pci 0000:0d:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 0e-0f] add_size 100000 add_align 100000
pci 0000:0c:00.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 0d-0f] add_size 300000 add_align 100000
pci 0000:0c:00.0: bridge window [mem 0x00100000-0x002fffff] to [bus 0d-0f] add_size 100000 add_align 100000
pci 0000:0d:00.0: check [io  0x1000-0x1fff
pci 0000:0d:00.0: check [mem 0x00100000-0x001fffff]
pci 0000:0d:00.0: check [mem 0x00100000-0x001fffff 64bit pref]
pci 0000:0c:00.0: BAR 14: assigned [mem 0x10400000-0x105fffff]
pci 0000:0c:00.0: BAR 15: assigned [mem 0x10600000-0x106fffff 64bit pref]
pci 0000:0c:00.0: BAR 0: assigned [mem 0x10740000-0x10740fff]
pci 0000:0c:00.0: BAR 13: no space for [io  size 0x2000]
pci 0000:0c:00.0: BAR 13: failed to assign [io  size 0x2000]
pci 0000:0d:00.0: BAR 14: assigned [mem 0x10400000-0x105fffff]
pci 0000:0d:00.0: BAR 15: assigned [mem 0x10600000-0x106fffff 64bit pref]      

> I will be on vacation starting
> tomorrow for the whole next week so if nothing else helps then I suppose
> we should revert that commit for now.
> 
> I can look at this further after I come back.

Enjoy your vacation.  I might get time to dig a bit more whilst you are away
though probably not :(

Jonathan


> 
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index dc6a30ee6edf..637f1a1df409 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -1939,7 +1939,7 @@ static void pci_bridge_distribute_available_resources(struct pci_dev *bridge,
>  					       available_mmio_pref);
>  }
>  
> -static bool pci_bridge_resources_not_assigned(struct pci_dev *dev)
> +static bool pci_bridge_resources_assigned(struct pci_dev *dev)
>  {
>  	const struct resource *r;
>  
> @@ -1951,16 +1951,19 @@ static bool pci_bridge_resources_not_assigned(struct pci_dev *dev)
>  	 * in the same way we do with the normal hotplug case.
>  	 */
>  	r = &dev->resource[PCI_BRIDGE_IO_WINDOW];
> -	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
> -		return false;
> +	dev_info(dev->dev, "check %pR\n", r);

&dev->dev 

> +	if (r->flags && !(r->flags & IORESOURCE_STARTALIGN))
> +		return true;
>  	r = &dev->resource[PCI_BRIDGE_MEM_WINDOW];
> -	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
> -		return false;
> +	dev_info(dev->dev, "check %pR\n", r);
> +	if (r->flags && !(r->flags & IORESOURCE_STARTALIGN))
> +		return true;
>  	r = &dev->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
> -	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
> -		return false;
> +	dev_info(dev->dev, "check %pR\n", r);
> +	if (r->flags && !(r->flags & IORESOURCE_STARTALIGN))
> +		return true;
>  
> -	return true;
> +	return false;
>  }
>  
>  static void pci_root_bus_distribute_available_resources(struct pci_bus *bus,
> @@ -1979,7 +1982,7 @@ static void pci_root_bus_distribute_available_resources(struct pci_bus *bus,
>  		 * Need to check "bridge" here too because it is NULL
>  		 * in case of root bus.
>  		 */
> -		if (bridge && pci_bridge_resources_not_assigned(dev)) {
> +		if (bridge && !pci_bridge_resources_assigned(dev)) {
>  			pci_bridge_distribute_available_resources(bridge, add_list);
>  			/*
>  			 * There is only PCIe upstream port on the bus
> 
> 

Re: Regression: Re: [PATCH v2 4/6] PCI: Distribute available resources for root buses too

[Mika Westerberg]

Hi,

On Fri, Oct 14, 2022 at 03:48:58PM +0100, Jonathan Cameron wrote:
> > Thanks for the detailed report! I wonder if you could try the below
> > patch and see if it changes anything?
> Thanks for the quick response.
> 
> Doesn't fix it unfortunately.

I'm back now.

Trying to reproduce this with mainline kernel (arm64 defconfig) and the
following command line:

qemu-system-aarch64 \
        -M virt,nvdimm=on,gic-version=3 -m 4g,maxmem=8G,slots=8 -cpu max -smp 4 \
        -bios /usr/share/qemu-efi-aarch64/QEMU_EFI.fd \
        -nographic -no-reboot  \
        -kernel Image \
        -initrd rootfs.cpio.bz2 \
        -device pcie-root-port,port=0,id=root_port13,chassis=0,slot=2 \
        -device x3130-upstream,id=sw1,bus=root_port13,multifunction=on \
        -device e1000,bus=root_port13,addr=0.1 \
        -device xio3130-downstream,id=fun1,bus=sw1,chassis=0,slot=3 \
        -device e1000,bus=fun1

But the resulting PCIe topology is pretty flat:

# lspci
00:00.0 Host bridge: Red Hat, Inc. QEMU PCIe Host bridge
00:01.0 Ethernet controller: Red Hat, Inc. Virtio network device

I wonder what I'm missing here? Do I need to enable additional drivers
to get the topology to resemble yours?

Re: Regression: Re: [PATCH v2 4/6] PCI: Distribute available resources for root buses too

[Mika Westerberg]

On Mon, Oct 24, 2022 at 02:13:10PM +0300, Mika Westerberg wrote:
> Hi,
> 
> On Fri, Oct 14, 2022 at 03:48:58PM +0100, Jonathan Cameron wrote:
> > > Thanks for the detailed report! I wonder if you could try the below
> > > patch and see if it changes anything?
> > Thanks for the quick response.
> > 
> > Doesn't fix it unfortunately.
> 
> I'm back now.
> 
> Trying to reproduce this with mainline kernel (arm64 defconfig) and the
> following command line:
> 
> qemu-system-aarch64 \
>         -M virt,nvdimm=on,gic-version=3 -m 4g,maxmem=8G,slots=8 -cpu max -smp 4 \
>         -bios /usr/share/qemu-efi-aarch64/QEMU_EFI.fd \
>         -nographic -no-reboot  \
>         -kernel Image \
>         -initrd rootfs.cpio.bz2 \
>         -device pcie-root-port,port=0,id=root_port13,chassis=0,slot=2 \
>         -device x3130-upstream,id=sw1,bus=root_port13,multifunction=on \
>         -device e1000,bus=root_port13,addr=0.1 \
>         -device xio3130-downstream,id=fun1,bus=sw1,chassis=0,slot=3 \
>         -device e1000,bus=fun1
> 
> But the resulting PCIe topology is pretty flat:
> 
> # lspci
> 00:00.0 Host bridge: Red Hat, Inc. QEMU PCIe Host bridge
> 00:01.0 Ethernet controller: Red Hat, Inc. Virtio network device
> 
> I wonder what I'm missing here? Do I need to enable additional drivers
> to get the topology to resemble yours?

Nevermind, I was missing one \ in the command line ;-) Now I can see the
topology similar to yours.

Re: Regression: Re: [PATCH v2 4/6] PCI: Distribute available resources for root buses too

[Mika Westerberg]

Hi,

On Mon, Oct 24, 2022 at 02:25:12PM +0300, Mika Westerberg wrote:
> On Mon, Oct 24, 2022 at 02:13:10PM +0300, Mika Westerberg wrote:
> > Hi,
> > 
> > On Fri, Oct 14, 2022 at 03:48:58PM +0100, Jonathan Cameron wrote:
> > > > Thanks for the detailed report! I wonder if you could try the below
> > > > patch and see if it changes anything?
> > > Thanks for the quick response.
> > > 
> > > Doesn't fix it unfortunately.
> > 
> > I'm back now.
> > 
> > Trying to reproduce this with mainline kernel (arm64 defconfig) and the
> > following command line:
> > 
> > qemu-system-aarch64 \
> >         -M virt,nvdimm=on,gic-version=3 -m 4g,maxmem=8G,slots=8 -cpu max -smp 4 \
> >         -bios /usr/share/qemu-efi-aarch64/QEMU_EFI.fd \
> >         -nographic -no-reboot  \
> >         -kernel Image \
> >         -initrd rootfs.cpio.bz2 \
> >         -device pcie-root-port,port=0,id=root_port13,chassis=0,slot=2 \
> >         -device x3130-upstream,id=sw1,bus=root_port13,multifunction=on \
> >         -device e1000,bus=root_port13,addr=0.1 \
> >         -device xio3130-downstream,id=fun1,bus=sw1,chassis=0,slot=3 \
> >         -device e1000,bus=fun1
> > 
> > But the resulting PCIe topology is pretty flat:
> > 
> > # lspci
> > 00:00.0 Host bridge: Red Hat, Inc. QEMU PCIe Host bridge
> > 00:01.0 Ethernet controller: Red Hat, Inc. Virtio network device
> > 
> > I wonder what I'm missing here? Do I need to enable additional drivers
> > to get the topology to resemble yours?
> 
> Nevermind, I was missing one \ in the command line ;-) Now I can see the
> topology similar to yours.

I think I know what the problem is now - there is a multifunction device
with the switch upstream port and the resource distribution code is not
prepared to handle such (not sure how common this is in real hardware
but allowed by the PCIe spec).

Simple fix would be just ignore all resource distribution if we
encounter such topologies but I think can still allow it, just by
accounting the resources reserved for the multifunction device(s).

Can you try on your side so that you revert this revert:

  5632e2beaf9d ("Revert "PCI: Distribute available resources for root buses, too"")

and then apply the below patch and see if the problem goes away? Thanks!

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index dc6a30ee6edf..a7ca3fecf259 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1833,10 +1833,65 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
 	 * bridges below.
 	 */
 	if (hotplug_bridges + normal_bridges == 1) {
-		dev = list_first_entry(&bus->devices, struct pci_dev, bus_list);
-		if (dev->subordinate)
-			pci_bus_distribute_available_resources(dev->subordinate,
-				add_list, io, mmio, mmio_pref);
+		/* Upstream port must be the first */
+		bridge = list_first_entry(&bus->devices, struct pci_dev, bus_list);
+		if (!bridge->subordinate)
+			return;
+
+		/*
+		 * It is possible to have switch upstream port as a part
+		 * of multifunction device, although not too common. For
+		 * this reason reduce the resources occupied by the
+		 * other functions before distributing the rest.
+		 */
+		list_for_each_entry(dev, &bus->devices, bus_list) {
+			int i;
+
+			if (dev == bridge)
+				continue;
+
+			/*
+			 * It should be multifunction but if not stop
+			 * the distribution and bail out.
+			 */
+			if (!dev->multifunction)
+				return;
+
+			for (i = 0; i < PCI_ROM_RESOURCE; i++) {
+				const struct resource *dev_res = &dev->resource[i];
+				resource_size_t dev_sz;
+				struct resource *b_res;
+
+				if (dev_res->flags & IORESOURCE_IO) {
+					b_res = &io;
+				} else if (dev_res->flags & IORESOURCE_MEM) {
+					if (dev_res->flags & IORESOURCE_PREFETCH)
+						b_res = &mmio_pref;
+					else
+						b_res = &mmio;
+				} else {
+					continue;
+				}
+
+				/* Size aligned to bridge window */
+				align = pci_resource_alignment(bridge, b_res);
+				dev_sz = ALIGN(resource_size(dev_res), align);
+
+				pci_dbg(dev, "%pR aligned to %llx\n", dev_res,
+					dev_sz);
+
+				if (dev_sz >= resource_size(b_res))
+					memset(b_res, 0, sizeof(*b_res));
+				else
+					b_res->end -= dev_sz;
+
+				pci_dbg(bridge, "updated available to %pR\n", b_res);
+			}
+		}
+
+		pci_bus_distribute_available_resources(bridge->subordinate,
+						       add_list, io, mmio,
+						       mmio_pref);
 		return;
 	}
 

Re: Regression: Re: [PATCH v2 4/6] PCI: Distribute available resources for root buses too

[Andy Shevchenko]

On Tue, Oct 25, 2022 at 03:36:06PM +0300, Mika Westerberg wrote:
> On Mon, Oct 24, 2022 at 02:25:12PM +0300, Mika Westerberg wrote:

Just for the record in case this code will formally go out

...

> +			for (i = 0; i < PCI_ROM_RESOURCE; i++) {
> +				const struct resource *dev_res = &dev->resource[i];

I believe this is a good candidate to have

#define for_each_pci_dev_resource(dev, res)			\
	for (unsigned int i = 0;				\
	     res = &(dev)->resource[i], i < PCI_ROM_RESOURCE;	\
	     i++)

Since we have many places in the kernel with such a snippet.

> +			}

-- 
With Best Regards,
Andy Shevchenko

Re: Regression: Re: [PATCH v2 4/6] PCI: Distribute available resources for root buses too

[Mika Westerberg]

Hi Andy,

On Tue, Oct 25, 2022 at 04:23:27PM +0300, Andy Shevchenko wrote:
> On Tue, Oct 25, 2022 at 03:36:06PM +0300, Mika Westerberg wrote:
> > On Mon, Oct 24, 2022 at 02:25:12PM +0300, Mika Westerberg wrote:
> 
> Just for the record in case this code will formally go out
> 
> ...
> 
> > +			for (i = 0; i < PCI_ROM_RESOURCE; i++) {
> > +				const struct resource *dev_res = &dev->resource[i];
> 
> I believe this is a good candidate to have
> 
> #define for_each_pci_dev_resource(dev, res)			\
> 	for (unsigned int i = 0;				\
> 	     res = &(dev)->resource[i], i < PCI_ROM_RESOURCE;	\
> 	     i++)
> 
> Since we have many places in the kernel with such a snippet.

Sure makes sense, but I think that should be a separate patch series.

Re: Regression: Re: [PATCH v2 4/6] PCI: Distribute available resources for root buses too

[Jonathan Cameron]

On Tue, 25 Oct 2022 15:36:06 +0300
Mika Westerberg <mika.westerberg@linux.intel.com> wrote:

> Hi,
> 
> On Mon, Oct 24, 2022 at 02:25:12PM +0300, Mika Westerberg wrote:
> > On Mon, Oct 24, 2022 at 02:13:10PM +0300, Mika Westerberg wrote:  
> > > Hi,
> > > 
> > > On Fri, Oct 14, 2022 at 03:48:58PM +0100, Jonathan Cameron wrote:  
> > > > > Thanks for the detailed report! I wonder if you could try the below
> > > > > patch and see if it changes anything?  
> > > > Thanks for the quick response.
> > > > 
> > > > Doesn't fix it unfortunately.  
> > > 
> > > I'm back now.
> > > 
> > > Trying to reproduce this with mainline kernel (arm64 defconfig) and the
> > > following command line:
> > > 
> > > qemu-system-aarch64 \
> > >         -M virt,nvdimm=on,gic-version=3 -m 4g,maxmem=8G,slots=8 -cpu max -smp 4 \
> > >         -bios /usr/share/qemu-efi-aarch64/QEMU_EFI.fd \
> > >         -nographic -no-reboot  \
> > >         -kernel Image \
> > >         -initrd rootfs.cpio.bz2 \
> > >         -device pcie-root-port,port=0,id=root_port13,chassis=0,slot=2 \
> > >         -device x3130-upstream,id=sw1,bus=root_port13,multifunction=on \
> > >         -device e1000,bus=root_port13,addr=0.1 \
> > >         -device xio3130-downstream,id=fun1,bus=sw1,chassis=0,slot=3 \
> > >         -device e1000,bus=fun1
> > > 
> > > But the resulting PCIe topology is pretty flat:
> > > 
> > > # lspci
> > > 00:00.0 Host bridge: Red Hat, Inc. QEMU PCIe Host bridge
> > > 00:01.0 Ethernet controller: Red Hat, Inc. Virtio network device
> > > 
> > > I wonder what I'm missing here? Do I need to enable additional drivers
> > > to get the topology to resemble yours?  
> > 
> > Nevermind, I was missing one \ in the command line ;-) Now I can see the
> > topology similar to yours.  
> 
> I think I know what the problem is now - there is a multifunction device
> with the switch upstream port and the resource distribution code is not
> prepared to handle such (not sure how common this is in real hardware
> but allowed by the PCIe spec).
> 
> Simple fix would be just ignore all resource distribution if we
> encounter such topologies but I think can still allow it, just by
> accounting the resources reserved for the multifunction device(s).
> 
> Can you try on your side so that you revert this revert:
> 
>   5632e2beaf9d ("Revert "PCI: Distribute available resources for root buses, too"")
> 
> and then apply the below patch and see if the problem goes away? Thanks!

Looks good on my more complex setup that I originally hit this problem on.

A comment on the comment inline.

> 
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index dc6a30ee6edf..a7ca3fecf259 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -1833,10 +1833,65 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
>  	 * bridges below.
>  	 */
>  	if (hotplug_bridges + normal_bridges == 1) {
> -		dev = list_first_entry(&bus->devices, struct pci_dev, bus_list);
> -		if (dev->subordinate)
> -			pci_bus_distribute_available_resources(dev->subordinate,
> -				add_list, io, mmio, mmio_pref);
> +		/* Upstream port must be the first */
> +		bridge = list_first_entry(&bus->devices, struct pci_dev, bus_list);
> +		if (!bridge->subordinate)
> +			return;
> +
> +		/*
> +		 * It is possible to have switch upstream port as a part
> +		 * of multifunction device, although not too common. For
> +		 * this reason reduce the resources occupied by the
> +		 * other functions before distributing the rest.
> +		 */

I 'think' it's quite common. I don't have one to hand but
drivers/pci/switches/switchtec.c has drivers for a management function that I
think are an additional function alongside the USP on a wide range of
switch chips.  It's possible those actually sit on their own port though or
pretend to be below a DSP.

> +		list_for_each_entry(dev, &bus->devices, bus_list) {
> +			int i;
> +
> +			if (dev == bridge)
> +				continue;
> +
> +			/*
> +			 * It should be multifunction but if not stop
> +			 * the distribution and bail out.
> +			 */
> +			if (!dev->multifunction)
> +				return;
> +
> +			for (i = 0; i < PCI_ROM_RESOURCE; i++) {
> +				const struct resource *dev_res = &dev->resource[i];
> +				resource_size_t dev_sz;
> +				struct resource *b_res;
> +
> +				if (dev_res->flags & IORESOURCE_IO) {
> +					b_res = &io;
> +				} else if (dev_res->flags & IORESOURCE_MEM) {
> +					if (dev_res->flags & IORESOURCE_PREFETCH)
> +						b_res = &mmio_pref;
> +					else
> +						b_res = &mmio;
> +				} else {
> +					continue;
> +				}
> +
> +				/* Size aligned to bridge window */
> +				align = pci_resource_alignment(bridge, b_res);
> +				dev_sz = ALIGN(resource_size(dev_res), align);
> +
> +				pci_dbg(dev, "%pR aligned to %llx\n", dev_res,
> +					dev_sz);
> +
> +				if (dev_sz >= resource_size(b_res))
> +					memset(b_res, 0, sizeof(*b_res));
> +				else
> +					b_res->end -= dev_sz;
> +
> +				pci_dbg(bridge, "updated available to %pR\n", b_res);
> +			}
> +		}
> +
> +		pci_bus_distribute_available_resources(bridge->subordinate,
> +						       add_list, io, mmio,
> +						       mmio_pref);
>  		return;
>  	}
>  

Re: Regression: Re: [PATCH v2 4/6] PCI: Distribute available resources for root buses too

[Mika Westerberg]

On Tue, Oct 25, 2022 at 03:05:00PM +0100, Jonathan Cameron wrote:
> On Tue, 25 Oct 2022 15:36:06 +0300
> Mika Westerberg <mika.westerberg@linux.intel.com> wrote:
> 
> > Hi,
> > 
> > On Mon, Oct 24, 2022 at 02:25:12PM +0300, Mika Westerberg wrote:
> > > On Mon, Oct 24, 2022 at 02:13:10PM +0300, Mika Westerberg wrote:  
> > > > Hi,
> > > > 
> > > > On Fri, Oct 14, 2022 at 03:48:58PM +0100, Jonathan Cameron wrote:  
> > > > > > Thanks for the detailed report! I wonder if you could try the below
> > > > > > patch and see if it changes anything?  
> > > > > Thanks for the quick response.
> > > > > 
> > > > > Doesn't fix it unfortunately.  
> > > > 
> > > > I'm back now.
> > > > 
> > > > Trying to reproduce this with mainline kernel (arm64 defconfig) and the
> > > > following command line:
> > > > 
> > > > qemu-system-aarch64 \
> > > >         -M virt,nvdimm=on,gic-version=3 -m 4g,maxmem=8G,slots=8 -cpu max -smp 4 \
> > > >         -bios /usr/share/qemu-efi-aarch64/QEMU_EFI.fd \
> > > >         -nographic -no-reboot  \
> > > >         -kernel Image \
> > > >         -initrd rootfs.cpio.bz2 \
> > > >         -device pcie-root-port,port=0,id=root_port13,chassis=0,slot=2 \
> > > >         -device x3130-upstream,id=sw1,bus=root_port13,multifunction=on \
> > > >         -device e1000,bus=root_port13,addr=0.1 \
> > > >         -device xio3130-downstream,id=fun1,bus=sw1,chassis=0,slot=3 \
> > > >         -device e1000,bus=fun1
> > > > 
> > > > But the resulting PCIe topology is pretty flat:
> > > > 
> > > > # lspci
> > > > 00:00.0 Host bridge: Red Hat, Inc. QEMU PCIe Host bridge
> > > > 00:01.0 Ethernet controller: Red Hat, Inc. Virtio network device
> > > > 
> > > > I wonder what I'm missing here? Do I need to enable additional drivers
> > > > to get the topology to resemble yours?  
> > > 
> > > Nevermind, I was missing one \ in the command line ;-) Now I can see the
> > > topology similar to yours.  
> > 
> > I think I know what the problem is now - there is a multifunction device
> > with the switch upstream port and the resource distribution code is not
> > prepared to handle such (not sure how common this is in real hardware
> > but allowed by the PCIe spec).
> > 
> > Simple fix would be just ignore all resource distribution if we
> > encounter such topologies but I think can still allow it, just by
> > accounting the resources reserved for the multifunction device(s).
> > 
> > Can you try on your side so that you revert this revert:
> > 
> >   5632e2beaf9d ("Revert "PCI: Distribute available resources for root buses, too"")
> > 
> > and then apply the below patch and see if the problem goes away? Thanks!
> 
> Looks good on my more complex setup that I originally hit this problem on.

Thanks for checking!

> 
> A comment on the comment inline.
> 
> > 
> > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> > index dc6a30ee6edf..a7ca3fecf259 100644
> > --- a/drivers/pci/setup-bus.c
> > +++ b/drivers/pci/setup-bus.c
> > @@ -1833,10 +1833,65 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
> >  	 * bridges below.
> >  	 */
> >  	if (hotplug_bridges + normal_bridges == 1) {
> > -		dev = list_first_entry(&bus->devices, struct pci_dev, bus_list);
> > -		if (dev->subordinate)
> > -			pci_bus_distribute_available_resources(dev->subordinate,
> > -				add_list, io, mmio, mmio_pref);
> > +		/* Upstream port must be the first */
> > +		bridge = list_first_entry(&bus->devices, struct pci_dev, bus_list);
> > +		if (!bridge->subordinate)
> > +			return;
> > +
> > +		/*
> > +		 * It is possible to have switch upstream port as a part
> > +		 * of multifunction device, although not too common. For
> > +		 * this reason reduce the resources occupied by the
> > +		 * other functions before distributing the rest.
> > +		 */
> 
> I 'think' it's quite common. I don't have one to hand but
> drivers/pci/switches/switchtec.c has drivers for a management function that I
> think are an additional function alongside the USP on a wide range of
> switch chips.  It's possible those actually sit on their own port though or
> pretend to be below a DSP.

I see. Okay, I will update the comment accordingly and submit as a formal
patch along with the revert of the revert if no objections.

Re: Regression: Re: [PATCH v2 4/6] PCI: Distribute available resources for root buses too #forregzbot

[Thorsten Leemhuis]

[Note: this mail is primarily send for documentation purposes and/or for
regzbot, my Linux kernel regression tracking bot. That's why I removed
most or all folks from the list of recipients, but left any that looked
like a mailing lists. These mails usually contain '#forregzbot' in the
subject, to make them easy to spot and filter out.]

[TLDR: I'm adding this regression report to the list of tracked
regressions; all text from me you find below is based on a few templates
paragraphs you might have encountered already already in similar form.]

Hi, this is your Linux kernel regression tracker. Thanks for the report.
To be sure below issue doesn't fall through the cracks unnoticed, I'm
adding it to regzbot, my Linux kernel regression tracking bot:

#regzbot ^introduced
#regzbot title
#regzbot ignore-activity

This isn't a regression? This issue or a fix for it are already
discussed somewhere else? It was fixed already? You want to clarify when
the regression started to happen? Or point out I got the title or
something else totally wrong? Then just reply -- ideally with also
telling regzbot about it, as explained here:
https://linux-regtracking.leemhuis.info/tracked-regression/

Reminder for developers: When fixing the issue, add 'Link:' tags
pointing to the report (the mail this one replies to), as explained for
in the Linux kernel's documentation; above webpage explains why this is
important for tracked regressions.

Thanks for the report. To be sure below issue doesn't fall through the
cracks unnoticed, I'm adding it to regzbot, my Linux kernel regression
tracking bot:

#regzbot ^introduced e96e27fc6f79
#regzbot title pci: probe errors in qemu
#regzbot ignore-activity

This isn't a regression? This issue or a fix for it are already
discussed somewhere else? It was fixed already? You want to clarify when
the regression started to happen? Or point out I got the title or
something else totally wrong? Then just reply -- ideally with also
telling regzbot about it, as explained here:
https://linux-regtracking.leemhuis.info/tracked-regression/

Reminder for developers: When fixing the issue, add 'Link:' tags
pointing to the report (the mail this one replies to), as explained for
in the Linux kernel's documentation; above webpage explains why this is
important for tracked regressions.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)

P.S.: As the Linux kernel's regression tracker I deal with a lot of
reports and sometimes miss something important when writing mails like
this. If that's the case here, don't hesitate to tell me in a public
reply, it's in everyone's interest to set the public record straight.

On 14.10.22 13:45, Jonathan Cameron wrote:
> On Mon,  5 Sep 2022 11:02:30 +0300
> Mika Westerberg <mika.westerberg@linux.intel.com> wrote:
> 
>> Currently we distribute the spare resources only upon hot-add so if
>> there are PCI devices connected already when the initial root bus scan
>> is done, and they have not been fully configured by the BIOS, we may end
>> up allocating resources just enough to cover only what is currently
>> there. If some of those devices are hotplug bridges themselves we do not
>> leave any additional resource space for future expansion.
>>
>> For this reason distribute the available resources for root buses too to
>> make this work the same way we do in the normal hotplug case.
>>
>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=216000
>> Reported-by: Chris Chiu <chris.chiu@canonical.com>
>> Tested-by: Chris Chiu <chris.chiu@canonical.com>
>> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>> ---
> 
> Early days, but I have a regression that's bisecting to this patch
> after I did an optimistic checkout of mainline mid merge window.
> 
> Initial platform was QEMU emulation of CXL on arm64 with EDK2 / ACPI etc.
> That uses an extended version of the PCI eXpander Bus (PXB) with extended
> version of the emulated pci root ports.  Particular test was
> 
> 1 PXB, 2 RP, below first RP switch USP, with two functions (USP and
> a stand along switch CCI), below that 4 DSP each with a CXL type 3 device.
> 
> Clearly something wrong with the error handling in CXL code as it goes boom
> spectacularly.  I'll address that separately.  Anyhow, setup way to complex
> to debug easily. 
> 
> Anyhow to make this easier for others to poke I set up equivalent with pxb-pcie
> etc and it happens there.  Everything works with the exception of additional
> functions on USP.
> 
> Next up in minimal test case (could be more minimal but I'm lazy) is 
> 
> ../qemu/bin/native/aarch64-softmmu/qemu-system-aarch64 -M virt,nvdimm=on,gic-version=3,cxl=on -m 4g,maxmem=8G,slots=8 -cpu max -smp 4 \
>  -kernel Image \
>  -drive if=none,file=full.qcow2,format=qcow2,id=hd \
>  -device pcie-root-port,id=root_port1 -device virtio-blk-pci,drive=hd \
>  -netdev type=user,id=mynet,hostfwd=tcp::5555-:22 \
>  -device virtio-net-pci,netdev=mynet,id=bob \
>  -nographic -no-reboot -append 'earlycon root=/dev/vda2 fsck.mode=skip tp_printk maxcpus=4' \
>  -monitor telnet:127.0.0.1:1235,server,nowait -bios QEMU_EFI.fd \
>  -object memory-backend-ram,size=4G,id=mem0 \
>  -numa node,nodeid=0,cpus=0-3,memdev=mem0 \
> # Interesting part follows:
>  -device pcie-root-port,port=0,id=root_port13,chassis=0,slot=2 \
>  -device x3130-upstream,id=sw1,bus=root_port13,multifunction=on \
>  -device e1000,bus=root_port13,addr=0.1 \
>  -device xio3130-downstream,id=fun1,bus=sw1,chassis=0,slot=3\
>  -device e1000,bus=fun1
> 
> 
> Error message on failure to probe my switch integrated e1000 (who doesn't have one of
> those - lets pretend it's a more common switch PMU function or something like
> that) is :
>  e1000 0000:02:00.1: can't ioremap BAR 0: [??? 0x00000000 flags 0x0]
> 
> With this patch reverted it works as normal and the e1000 driver comes up.
> 
> Possibly useful stuff follows:
> 
> # lspci -tv
> -[0000:00]-+-00.0  Red Hat, Inc. QEMU PCIe Host bridge
>            +-01.0-[01]--
>            +-02.0  Red Hat, Inc. Virtio block device
>            +-03.0  Red Hat, Inc. Virtio network device
>            \-04.0-[02-04]--+-00.0-[03-04]----00.0-[04]----00.0  Intel Corporation 82540EM Gigabit Ethernet Controller
>                            \-00.1  Intel Corporation 82540EM Gigabit Ethernet Controller
> 
> with patch in place.
> //without patch
> Note I aligned by hand so may be errorr.
> 
> # dmesg | grep pci                                  
> pci_bus 0000:00: root bus resource [mem 0x10000000-0x3efeffff window]
> pci_bus 0000:00: root bus resource [io  0x0000-0xffff window]
> pci_bus 0000:00: root bus resource [mem 0x8000000000-0xffffffffff window]
> pci_bus 0000:00: root bus resource [bus 00-ff]
> pci 0000:00:00.0: [1b36:0008] type 00 class 0x060000
> pci 0000:00:01.0: [1b36:000c] type 01 class 0x060400
> pci 0000:00:01.0: reg 0x10: [mem 0x10643000-0x10643fff]
> pci 0000:00:02.0: [1af4:1001] type 00 class 0x010000
> pci 0000:00:02.0: reg 0x10: [io  0x2200-0x227f]
> pci 0000:00:02.0: reg 0x14: [mem 0x10642000-0x10642fff]
> pci 0000:00:02.0: reg 0x20: [mem 0x8000000000-0x8000003fff 64bit pref]
> pci 0000:00:03.0: [1af4:1000] type 00 class 0x020000
> pci 0000:00:03.0: reg 0x10: [io  0x2280-0x229f]
> pci 0000:00:03.0: reg 0x14: [mem 0x10641000-0x10641fff]
> pci 0000:00:03.0: reg 0x20: [mem 0x8000004000-0x8000007fff 64bit pref]
> pci 0000:00:03.0: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
> pci 0000:00:04.0: [1b36:000c] type 01 class 0x060400
> pci 0000:00:04.0: reg 0x10: [mem 0x10640000-0x10640fff]
> pci 0000:02:00.0: [104c:8232] type 01 class 0x060400
> pci 0000:02:00.1: [8086:100e] type 00 class 0x020000
> pci 0000:02:00.1: reg 0x10: [mem 0x10200000-0x1021ffff]
> pci 0000:02:00.1: reg 0x14: [io  0x1000-0x103f]
> pci 0000:02:00.1: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
> pci 0000:03:00.0: [104c:8233] type 01 class 0x060400
> pci 0000:04:00.0: [8086:100e] type 00 class 0x020000
> pci 0000:04:00.0: reg 0x10: [mem 0x10000000-0x1001ffff]
> pci 0000:04:00.0: reg 0x14: [io  0x0000-0x003f]
> pci 0000:04:00.0: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
> pci 0000:00:01.0: bridge window [io  0x1000-0x0fff] to [bus 01] add_size 1000
> pci 0000:00:01.0: bridge window [mem 0x00100000-0x000fffff 64bit pref] to [bus 01] add_size 200000 add_align 100000
> pci 0000:00:01.0: bridge window [mem 0x00100000-0x000fffff] to [bus 01] add_size 200000 add_align 100000
> pci 0000:03:00.0: bridge window [mem 0x00100000-0x000fffff 64bit pref] to [bus 04] add_size 200000 add_align 100000
> pci 0000:03:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 04] add_size 100000 add_align 100000
> pci 0000:02:00.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 03-04] add_size 200000 add_align 100000
> pci 0000:02:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 03-04] add_size 100000 add_align 100000
> pci 0000:00:04.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 02-04] add_size 300000 add_align 100000
> pci 0000:00:04.0: bridge window [mem 0x00100000-0x002fffff] to [bus 02-04] add_size 100000 add_align 100000
> pci 0000:00:01.0: BAR 14: assigned [mem 0x10000000-0x101fffff]
> pci 0000:00:01.0: BAR 15: assigned [mem 0x8000000000-0x80001fffff 64bit pref]
> pci 0000:00:04.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
> // pci 0000:00:04.0: BAR 14: assigned [mem 0x10200000-0x104fffff]
> pci 0000:00:04.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:00:04.0: BAR 15: assigned [mem 0x8000200000-0x80005fffff 64bit pref]
> pci 0000:00:03.0: BAR 6: assigned [mem 0x10400000-0x1043ffff pref]
> // pci 0000:00:03.0: BAR 6: assigned [mem 0x10500000-0x1053ffff pref]
> pci 0000:00:02.0: BAR 4: assigned [mem 0x8000300000-0x8000303fff 64bit pref]
> //  pci 0000:00:02.0: BAR 4: assigned [mem 0x8000600000-0x8000603fff 64bit pref]
> pci 0000:00:03.0: BAR 4: assigned [mem 0x8000304000-0x8000307fff 64bit pref]
> //  pci 0000:00:03.0: BAR 4: assigned [mem 0x8000604000-0x8000607fff 64bit pref]
> pci 0000:00:01.0: BAR 0: assigned [mem 0x10440000-0x10440fff]
> //  pci 0000:00:01.0: BAR 0: assigned [mem 0x10540000-0x10540fff]
> pci 0000:00:01.0: BAR 13: assigned [io  0x1000-0x1fff]
> pci 0000:00:02.0: BAR 1: assigned [mem 0x10441000-0x10441fff]
> //  pci 0000:00:02.0: BAR 1: assigned [mem 0x10541000-0x10541fff]
> pci 0000:00:03.0: BAR 1: assigned [mem 0x10442000-0x10442fff]
> // pci 0000:00:03.0: BAR 1: assigned [mem 0x10542000-0x10542fff]
> pci 0000:00:04.0: BAR 0: assigned [mem 0x10443000-0x10443fff]
> // pci 0000:00:01.0: BAR 0: assigned [mem 0x10540000-0x10540fff]
> pci 0000:00:04.0: BAR 13: assigned [io  0x2000-0x3fff]
> pci 0000:00:02.0: BAR 0: assigned [io  0x4000-0x407f]
> pci 0000:00:03.0: BAR 0: assigned [io  0x4080-0x409f]
> pci 0000:00:01.0: PCI bridge to [bus 01]
> pci 0000:00:01.0:   bridge window [io  0x1000-0x1fff]
> pci 0000:00:01.0:   bridge window [mem 0x10000000-0x101fffff]
> pci 0000:00:01.0:   bridge window [mem 0x8000000000-0x80001fffff 64bit pref]
> pci 0000:02:00.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
> pci 0000:02:00.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:02:00.0: BAR 15: assigned [mem 0x8000200000-0x80004fffff 64bit pref]
> pci 0000:02:00.1: BAR 6: no space for [mem size 0x00040000 pref]
> pci 0000:02:00.1: BAR 6: failed to assign [mem size 0x00040000 pref]
> // pci 0000:02:00.1: BAR 6: assigned [mem 0x10400000-0x1043ffff pref]
> pci 0000:02:00.1: BAR 0: failed to assign [mem size 0x00020000]
> // pci 0000:02:00.1: BAR 0: assigned [mem 0x10440000-0x1045ffff]
> pci 0000:02:00.0: BAR 13: assigned [io  0x2000-0x3fff]
> pci 0000:02:00.1: BAR 1: no space for [io  size 0x0040]
> // pci 0000:02:00.1: BAR 1: assigned [io  0x3000-0x303f]
> pci 0000:02:00.1: BAR 1: failed to assign [io  size 0x0040]
> pci 0000:03:00.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
> pci 0000:03:00.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:03:00.0: BAR 15: assigned [mem 0x8000200000-0x80003fffff 64bit pref]
> pci 0000:03:00.0: BAR 13: assigned [io  0x2000-0x3fff]
> // pci 0000:03:00.0: BAR 13: assigned [io  0x2000-0x2fff]
> pci 0000:04:00.0: BAR 6: assigned [mem 0x10200000-0x1023ffff pref]
> pci 0000:04:00.0: BAR 0: assigned [mem 0x10240000-0x1025ffff]
> pci 0000:04:00.0: BAR 1: assigned [io  0x2000-0x203f]
> pci 0000:03:00.0: PCI bridge to [bus 04]
> pci 0000:03:00.0:   bridge window [io  0x2000-0x3fff]
> // pci 0000:03:00.0:   bridge window [io  0x2000-0x2fff]
> pci 0000:03:00.0:   bridge window [mem 0x10200000-0x103fffff]
> pci 0000:03:00.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:03:00.0:   bridge window [mem 0x8000200000-0x80003fffff 64bit pref]
> pci 0000:02:00.0: PCI bridge to [bus 03-04]
> pci 0000:02:00.0:   bridge window [io  0x2000-0x3fff]
> // pci 0000:02:00.0:   bridge window [io  0x2000-0x2fff]
> pci 0000:02:00.0:   bridge window [mem 0x10200000-0x103fffff]
> pci 0000:02:00.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:02:00.0:   bridge window [mem 0x8000200000-0x80004fffff 64bit pref]
> pci 0000:00:04.0: PCI bridge to [bus 02-04]
> pci 0000:00:04.0:   bridge window [io  0x2000-0x3fff]
> pci 0000:00:04.0:   bridge window [mem 0x10200000-0x103fffff]
> // pci 0000:00:04.0:   bridge window [mem 0x10200000-0x104fffff]
> pci 0000:00:04.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:00:04.0:   bridge window [mem 0x8000200000-0x80005fffff 64bit pref]
> pci_bus 0000:00: Some PCI device resources are unassigned, try booting with pci=realloc
> // LINE NOT PRESENT
> pci_bus 0000:00: resource 4 [mem 0x10000000-0x3efeffff window]
> pci_bus 0000:00: resource 5 [io  0x0000-0xffff window]
> pci_bus 0000:00: resource 6 [mem 0x8000000000-0xffffffffff window]
> pci_bus 0000:01: resource 0 [io  0x1000-0x1fff]
> pci_bus 0000:01: resource 1 [mem 0x10000000-0x101fffff]
> pci_bus 0000:01: resource 2 [mem 0x8000000000-0x80001fffff 64bit pref]
> pci_bus 0000:02: resource 0 [io  0x2000-0x3fff]
> pci_bus 0000:02: resource 1 [mem 0x10200000-0x103fffff]
> // pci_bus 0000:02: resource 1 [mem 0x10200000-0x104fffff]
> pci_bus 0000:02: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
> //  pci_bus 0000:02: resource 2 [mem 0x8000200000-0x80005fffff 64bit pref]
> pci_bus 0000:03: resource 0 [io  0x2000-0x3fff]
> // pci_bus 0000:03: resource 0 [io  0x2000-0x2fff]
> pci_bus 0000:03: resource 1 [mem 0x10200000-0x103fffff]
> pci_bus 0000:03: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci_bus 0000:03: resource 2 [mem 0x8000200000-0x80004fffff 64bit pref]
> pci_bus 0000:04: resource 0 [io  0x2000-0x3fff]
> // pci_bus 0000:04: resource 0 [io  0x2000-0x2fff]
> pci_bus 0000:04: resource 1 [mem 0x10200000-0x103fffff]
> // pci_bus 0000:04: resource 1 [mem 0x10200000-0x103fffff]
> pci_bus 0000:04: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci_bus 0000:04: resource 2 [mem 0x8000200000-0x80003fffff 64bit pref]
> pcieport 0000:00:01.0: PME: Signaling with IRQ 51
> pcieport 0000:00:01.0: AER: enabled with IRQ 51
> pcieport 0000:00:01.0: pciehp: Slot #0 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep+
> pcieport 0000:00:04.0: PME: Signaling with IRQ 52
> pcieport 0000:00:04.0: AER: enabled with IRQ 52
> pcieport 0000:00:04.0: pciehp: Slot #2 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep+
> pcieport 0000:03:00.0: pciehp: Slot #3 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep-
> virtio-pci 0000:00:02.0: enabling device (0000 -> 0003)
> virtio-pci 0000:00:03.0: enabling device (0000 -> 0003)
> 
> All suggestions of things to test and other useful info to provide welcome.
> 
>>  drivers/pci/setup-bus.c | 62 ++++++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 61 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
>> index 3b981da0fb4e..df9fc974b313 100644
>> --- a/drivers/pci/setup-bus.c
>> +++ b/drivers/pci/setup-bus.c
>> @@ -1768,7 +1768,10 @@ static void adjust_bridge_window(struct pci_dev *bridge, struct resource *res,
>>  	}
>>  
>>  	res->end = res->start + new_size - 1;
>> -	remove_from_list(add_list, res);
>> +
>> +	/* If the resource is part of the add_list remove it now */
>> +	if (add_list)
>> +		remove_from_list(add_list, res);
>>  }
>>  
>>  static void pci_bus_distribute_available_resources(struct pci_bus *bus,
>> @@ -1923,6 +1926,8 @@ static void pci_bridge_distribute_available_resources(struct pci_dev *bridge,
>>  	if (!bridge->is_hotplug_bridge)
>>  		return;
>>  
>> +	pci_dbg(bridge, "distributing available resources\n");
>> +
>>  	/* Take the initial extra resources from the hotplug port */
>>  	available_io = bridge->resource[PCI_BRIDGE_IO_WINDOW];
>>  	available_mmio = bridge->resource[PCI_BRIDGE_MEM_WINDOW];
>> @@ -1934,6 +1939,59 @@ static void pci_bridge_distribute_available_resources(struct pci_dev *bridge,
>>  					       available_mmio_pref);
>>  }
>>  
>> +static bool pci_bridge_resources_not_assigned(struct pci_dev *dev)
>> +{
>> +	const struct resource *r;
>> +
>> +	/*
>> +	 * Check the child device's resources and if they are not yet
>> +	 * assigned it means we are configuring them (not the boot
>> +	 * firmware) so we should be able to extend the upstream
>> +	 * bridge's (that's the hotplug downstream PCIe port) resources
>> +	 * in the same way we do with the normal hotplug case.
>> +	 */
>> +	r = &dev->resource[PCI_BRIDGE_IO_WINDOW];
>> +	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
>> +		return false;
>> +	r = &dev->resource[PCI_BRIDGE_MEM_WINDOW];
>> +	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
>> +		return false;
>> +	r = &dev->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
>> +	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
>> +		return false;
>> +
>> +	return true;
>> +}
>> +
>> +static void pci_root_bus_distribute_available_resources(struct pci_bus *bus,
>> +							struct list_head *add_list)
>> +{
>> +	struct pci_dev *dev, *bridge = bus->self;
>> +
>> +	for_each_pci_bridge(dev, bus) {
>> +		struct pci_bus *b;
>> +
>> +		b = dev->subordinate;
>> +		if (!b)
>> +			continue;
>> +
>> +		/*
>> +		 * Need to check "bridge" here too because it is NULL
>> +		 * in case of root bus.
>> +		 */
>> +		if (bridge && pci_bridge_resources_not_assigned(dev)) {
>> +			pci_bridge_distribute_available_resources(bridge, add_list);
>> +			/*
>> +			 * There is only PCIe upstream port on the bus
>> +			 * so we don't need to go futher.
>> +			 */
>> +			return;
>> +		}
>> +
>> +		pci_root_bus_distribute_available_resources(b, add_list);
>> +	}
>> +}
>> +
>>  /*
>>   * First try will not touch PCI bridge res.
>>   * Second and later try will clear small leaf bridge res.
>> @@ -1973,6 +2031,8 @@ void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus)
>>  	 */
>>  	__pci_bus_size_bridges(bus, add_list);
>>  
>> +	pci_root_bus_distribute_available_resources(bus, add_list);
>> +
>>  	/* Depth last, allocate resources and update the hardware. */
>>  	__pci_bus_assign_resources(bus, add_list, &fail_head);
>>  	if (add_list)
> 
> 
> 

Re: Regression: Re: [PATCH v2 4/6] PCI: Distribute available resources for root buses too #forregzbot

[Thorsten Leemhuis]

[Note: this mail is primarily send for documentation purposes and/or for
regzbot, my Linux kernel regression tracking bot. That's why I removed
most or all folks from the list of recipients, but left any that looked
like a mailing lists. These mails usually contain '#forregzbot' in the
subject, to make them easy to spot and filter out.]

[TLDR: I'm adding this regression report to the list of tracked
regressions; all text from me you find below is based on a few templates
paragraphs you might have encountered already already in similar form.]

Hi, this is your Linux kernel regression tracker. Thanks for the report.
To be sure below issue doesn't fall through the
cracks unnoticed, I'm adding it to regzbot, my Linux kernel regression
tracking bot:

#regzbot ^introduced e96e27fc6f79
#regzbot title pci: probe errors in qemu
#regzbot ignore-activity

This isn't a regression? This issue or a fix for it are already
discussed somewhere else? It was fixed already? You want to clarify when
the regression started to happen? Or point out I got the title or
something else totally wrong? Then just reply -- ideally with also
telling regzbot about it, as explained here:
https://linux-regtracking.leemhuis.info/tracked-regression/

Reminder for developers: When fixing the issue, add 'Link:' tags
pointing to the report (the mail this one replies to), as explained for
in the Linux kernel's documentation; above webpage explains why this is
important for tracked regressions.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)

P.S.: As the Linux kernel's regression tracker I deal with a lot of
reports and sometimes miss something important when writing mails like
this. If that's the case here, don't hesitate to tell me in a public
reply, it's in everyone's interest to set the public record straight.

On 14.10.22 13:45, Jonathan Cameron wrote:
> On Mon,  5 Sep 2022 11:02:30 +0300
> Mika Westerberg <mika.westerberg@linux.intel.com> wrote:
> 
>> Currently we distribute the spare resources only upon hot-add so if
>> there are PCI devices connected already when the initial root bus scan
>> is done, and they have not been fully configured by the BIOS, we may end
>> up allocating resources just enough to cover only what is currently
>> there. If some of those devices are hotplug bridges themselves we do not
>> leave any additional resource space for future expansion.
>>
>> For this reason distribute the available resources for root buses too to
>> make this work the same way we do in the normal hotplug case.
>>
>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=216000
>> Reported-by: Chris Chiu <chris.chiu@canonical.com>
>> Tested-by: Chris Chiu <chris.chiu@canonical.com>
>> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>> ---
> 
> Early days, but I have a regression that's bisecting to this patch
> after I did an optimistic checkout of mainline mid merge window.
> 
> Initial platform was QEMU emulation of CXL on arm64 with EDK2 / ACPI etc.
> That uses an extended version of the PCI eXpander Bus (PXB) with extended
> version of the emulated pci root ports.  Particular test was
> 
> 1 PXB, 2 RP, below first RP switch USP, with two functions (USP and
> a stand along switch CCI), below that 4 DSP each with a CXL type 3 device.
> 
> Clearly something wrong with the error handling in CXL code as it goes boom
> spectacularly.  I'll address that separately.  Anyhow, setup way to complex
> to debug easily. 
> 
> Anyhow to make this easier for others to poke I set up equivalent with pxb-pcie
> etc and it happens there.  Everything works with the exception of additional
> functions on USP.
> 
> Next up in minimal test case (could be more minimal but I'm lazy) is 
> 
> ../qemu/bin/native/aarch64-softmmu/qemu-system-aarch64 -M virt,nvdimm=on,gic-version=3,cxl=on -m 4g,maxmem=8G,slots=8 -cpu max -smp 4 \
>  -kernel Image \
>  -drive if=none,file=full.qcow2,format=qcow2,id=hd \
>  -device pcie-root-port,id=root_port1 -device virtio-blk-pci,drive=hd \
>  -netdev type=user,id=mynet,hostfwd=tcp::5555-:22 \
>  -device virtio-net-pci,netdev=mynet,id=bob \
>  -nographic -no-reboot -append 'earlycon root=/dev/vda2 fsck.mode=skip tp_printk maxcpus=4' \
>  -monitor telnet:127.0.0.1:1235,server,nowait -bios QEMU_EFI.fd \
>  -object memory-backend-ram,size=4G,id=mem0 \
>  -numa node,nodeid=0,cpus=0-3,memdev=mem0 \
> # Interesting part follows:
>  -device pcie-root-port,port=0,id=root_port13,chassis=0,slot=2 \
>  -device x3130-upstream,id=sw1,bus=root_port13,multifunction=on \
>  -device e1000,bus=root_port13,addr=0.1 \
>  -device xio3130-downstream,id=fun1,bus=sw1,chassis=0,slot=3\
>  -device e1000,bus=fun1
> 
> 
> Error message on failure to probe my switch integrated e1000 (who doesn't have one of
> those - lets pretend it's a more common switch PMU function or something like
> that) is :
>  e1000 0000:02:00.1: can't ioremap BAR 0: [??? 0x00000000 flags 0x0]
> 
> With this patch reverted it works as normal and the e1000 driver comes up.
> 
> Possibly useful stuff follows:
> 
> # lspci -tv
> -[0000:00]-+-00.0  Red Hat, Inc. QEMU PCIe Host bridge
>            +-01.0-[01]--
>            +-02.0  Red Hat, Inc. Virtio block device
>            +-03.0  Red Hat, Inc. Virtio network device
>            \-04.0-[02-04]--+-00.0-[03-04]----00.0-[04]----00.0  Intel Corporation 82540EM Gigabit Ethernet Controller
>                            \-00.1  Intel Corporation 82540EM Gigabit Ethernet Controller
> 
> with patch in place.
> //without patch
> Note I aligned by hand so may be errorr.
> 
> # dmesg | grep pci                                  
> pci_bus 0000:00: root bus resource [mem 0x10000000-0x3efeffff window]
> pci_bus 0000:00: root bus resource [io  0x0000-0xffff window]
> pci_bus 0000:00: root bus resource [mem 0x8000000000-0xffffffffff window]
> pci_bus 0000:00: root bus resource [bus 00-ff]
> pci 0000:00:00.0: [1b36:0008] type 00 class 0x060000
> pci 0000:00:01.0: [1b36:000c] type 01 class 0x060400
> pci 0000:00:01.0: reg 0x10: [mem 0x10643000-0x10643fff]
> pci 0000:00:02.0: [1af4:1001] type 00 class 0x010000
> pci 0000:00:02.0: reg 0x10: [io  0x2200-0x227f]
> pci 0000:00:02.0: reg 0x14: [mem 0x10642000-0x10642fff]
> pci 0000:00:02.0: reg 0x20: [mem 0x8000000000-0x8000003fff 64bit pref]
> pci 0000:00:03.0: [1af4:1000] type 00 class 0x020000
> pci 0000:00:03.0: reg 0x10: [io  0x2280-0x229f]
> pci 0000:00:03.0: reg 0x14: [mem 0x10641000-0x10641fff]
> pci 0000:00:03.0: reg 0x20: [mem 0x8000004000-0x8000007fff 64bit pref]
> pci 0000:00:03.0: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
> pci 0000:00:04.0: [1b36:000c] type 01 class 0x060400
> pci 0000:00:04.0: reg 0x10: [mem 0x10640000-0x10640fff]
> pci 0000:02:00.0: [104c:8232] type 01 class 0x060400
> pci 0000:02:00.1: [8086:100e] type 00 class 0x020000
> pci 0000:02:00.1: reg 0x10: [mem 0x10200000-0x1021ffff]
> pci 0000:02:00.1: reg 0x14: [io  0x1000-0x103f]
> pci 0000:02:00.1: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
> pci 0000:03:00.0: [104c:8233] type 01 class 0x060400
> pci 0000:04:00.0: [8086:100e] type 00 class 0x020000
> pci 0000:04:00.0: reg 0x10: [mem 0x10000000-0x1001ffff]
> pci 0000:04:00.0: reg 0x14: [io  0x0000-0x003f]
> pci 0000:04:00.0: reg 0x30: [mem 0xfffc0000-0xffffffff pref]
> pci 0000:00:01.0: bridge window [io  0x1000-0x0fff] to [bus 01] add_size 1000
> pci 0000:00:01.0: bridge window [mem 0x00100000-0x000fffff 64bit pref] to [bus 01] add_size 200000 add_align 100000
> pci 0000:00:01.0: bridge window [mem 0x00100000-0x000fffff] to [bus 01] add_size 200000 add_align 100000
> pci 0000:03:00.0: bridge window [mem 0x00100000-0x000fffff 64bit pref] to [bus 04] add_size 200000 add_align 100000
> pci 0000:03:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 04] add_size 100000 add_align 100000
> pci 0000:02:00.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 03-04] add_size 200000 add_align 100000
> pci 0000:02:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 03-04] add_size 100000 add_align 100000
> pci 0000:00:04.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 02-04] add_size 300000 add_align 100000
> pci 0000:00:04.0: bridge window [mem 0x00100000-0x002fffff] to [bus 02-04] add_size 100000 add_align 100000
> pci 0000:00:01.0: BAR 14: assigned [mem 0x10000000-0x101fffff]
> pci 0000:00:01.0: BAR 15: assigned [mem 0x8000000000-0x80001fffff 64bit pref]
> pci 0000:00:04.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
> // pci 0000:00:04.0: BAR 14: assigned [mem 0x10200000-0x104fffff]
> pci 0000:00:04.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:00:04.0: BAR 15: assigned [mem 0x8000200000-0x80005fffff 64bit pref]
> pci 0000:00:03.0: BAR 6: assigned [mem 0x10400000-0x1043ffff pref]
> // pci 0000:00:03.0: BAR 6: assigned [mem 0x10500000-0x1053ffff pref]
> pci 0000:00:02.0: BAR 4: assigned [mem 0x8000300000-0x8000303fff 64bit pref]
> //  pci 0000:00:02.0: BAR 4: assigned [mem 0x8000600000-0x8000603fff 64bit pref]
> pci 0000:00:03.0: BAR 4: assigned [mem 0x8000304000-0x8000307fff 64bit pref]
> //  pci 0000:00:03.0: BAR 4: assigned [mem 0x8000604000-0x8000607fff 64bit pref]
> pci 0000:00:01.0: BAR 0: assigned [mem 0x10440000-0x10440fff]
> //  pci 0000:00:01.0: BAR 0: assigned [mem 0x10540000-0x10540fff]
> pci 0000:00:01.0: BAR 13: assigned [io  0x1000-0x1fff]
> pci 0000:00:02.0: BAR 1: assigned [mem 0x10441000-0x10441fff]
> //  pci 0000:00:02.0: BAR 1: assigned [mem 0x10541000-0x10541fff]
> pci 0000:00:03.0: BAR 1: assigned [mem 0x10442000-0x10442fff]
> // pci 0000:00:03.0: BAR 1: assigned [mem 0x10542000-0x10542fff]
> pci 0000:00:04.0: BAR 0: assigned [mem 0x10443000-0x10443fff]
> // pci 0000:00:01.0: BAR 0: assigned [mem 0x10540000-0x10540fff]
> pci 0000:00:04.0: BAR 13: assigned [io  0x2000-0x3fff]
> pci 0000:00:02.0: BAR 0: assigned [io  0x4000-0x407f]
> pci 0000:00:03.0: BAR 0: assigned [io  0x4080-0x409f]
> pci 0000:00:01.0: PCI bridge to [bus 01]
> pci 0000:00:01.0:   bridge window [io  0x1000-0x1fff]
> pci 0000:00:01.0:   bridge window [mem 0x10000000-0x101fffff]
> pci 0000:00:01.0:   bridge window [mem 0x8000000000-0x80001fffff 64bit pref]
> pci 0000:02:00.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
> pci 0000:02:00.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:02:00.0: BAR 15: assigned [mem 0x8000200000-0x80004fffff 64bit pref]
> pci 0000:02:00.1: BAR 6: no space for [mem size 0x00040000 pref]
> pci 0000:02:00.1: BAR 6: failed to assign [mem size 0x00040000 pref]
> // pci 0000:02:00.1: BAR 6: assigned [mem 0x10400000-0x1043ffff pref]
> pci 0000:02:00.1: BAR 0: failed to assign [mem size 0x00020000]
> // pci 0000:02:00.1: BAR 0: assigned [mem 0x10440000-0x1045ffff]
> pci 0000:02:00.0: BAR 13: assigned [io  0x2000-0x3fff]
> pci 0000:02:00.1: BAR 1: no space for [io  size 0x0040]
> // pci 0000:02:00.1: BAR 1: assigned [io  0x3000-0x303f]
> pci 0000:02:00.1: BAR 1: failed to assign [io  size 0x0040]
> pci 0000:03:00.0: BAR 14: assigned [mem 0x10200000-0x103fffff]
> pci 0000:03:00.0: BAR 15: assigned [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:03:00.0: BAR 15: assigned [mem 0x8000200000-0x80003fffff 64bit pref]
> pci 0000:03:00.0: BAR 13: assigned [io  0x2000-0x3fff]
> // pci 0000:03:00.0: BAR 13: assigned [io  0x2000-0x2fff]
> pci 0000:04:00.0: BAR 6: assigned [mem 0x10200000-0x1023ffff pref]
> pci 0000:04:00.0: BAR 0: assigned [mem 0x10240000-0x1025ffff]
> pci 0000:04:00.0: BAR 1: assigned [io  0x2000-0x203f]
> pci 0000:03:00.0: PCI bridge to [bus 04]
> pci 0000:03:00.0:   bridge window [io  0x2000-0x3fff]
> // pci 0000:03:00.0:   bridge window [io  0x2000-0x2fff]
> pci 0000:03:00.0:   bridge window [mem 0x10200000-0x103fffff]
> pci 0000:03:00.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:03:00.0:   bridge window [mem 0x8000200000-0x80003fffff 64bit pref]
> pci 0000:02:00.0: PCI bridge to [bus 03-04]
> pci 0000:02:00.0:   bridge window [io  0x2000-0x3fff]
> // pci 0000:02:00.0:   bridge window [io  0x2000-0x2fff]
> pci 0000:02:00.0:   bridge window [mem 0x10200000-0x103fffff]
> pci 0000:02:00.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:02:00.0:   bridge window [mem 0x8000200000-0x80004fffff 64bit pref]
> pci 0000:00:04.0: PCI bridge to [bus 02-04]
> pci 0000:00:04.0:   bridge window [io  0x2000-0x3fff]
> pci 0000:00:04.0:   bridge window [mem 0x10200000-0x103fffff]
> // pci 0000:00:04.0:   bridge window [mem 0x10200000-0x104fffff]
> pci 0000:00:04.0:   bridge window [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci 0000:00:04.0:   bridge window [mem 0x8000200000-0x80005fffff 64bit pref]
> pci_bus 0000:00: Some PCI device resources are unassigned, try booting with pci=realloc
> // LINE NOT PRESENT
> pci_bus 0000:00: resource 4 [mem 0x10000000-0x3efeffff window]
> pci_bus 0000:00: resource 5 [io  0x0000-0xffff window]
> pci_bus 0000:00: resource 6 [mem 0x8000000000-0xffffffffff window]
> pci_bus 0000:01: resource 0 [io  0x1000-0x1fff]
> pci_bus 0000:01: resource 1 [mem 0x10000000-0x101fffff]
> pci_bus 0000:01: resource 2 [mem 0x8000000000-0x80001fffff 64bit pref]
> pci_bus 0000:02: resource 0 [io  0x2000-0x3fff]
> pci_bus 0000:02: resource 1 [mem 0x10200000-0x103fffff]
> // pci_bus 0000:02: resource 1 [mem 0x10200000-0x104fffff]
> pci_bus 0000:02: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
> //  pci_bus 0000:02: resource 2 [mem 0x8000200000-0x80005fffff 64bit pref]
> pci_bus 0000:03: resource 0 [io  0x2000-0x3fff]
> // pci_bus 0000:03: resource 0 [io  0x2000-0x2fff]
> pci_bus 0000:03: resource 1 [mem 0x10200000-0x103fffff]
> pci_bus 0000:03: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci_bus 0000:03: resource 2 [mem 0x8000200000-0x80004fffff 64bit pref]
> pci_bus 0000:04: resource 0 [io  0x2000-0x3fff]
> // pci_bus 0000:04: resource 0 [io  0x2000-0x2fff]
> pci_bus 0000:04: resource 1 [mem 0x10200000-0x103fffff]
> // pci_bus 0000:04: resource 1 [mem 0x10200000-0x103fffff]
> pci_bus 0000:04: resource 2 [mem 0x8000200000-0x80002fffff 64bit pref]
> // pci_bus 0000:04: resource 2 [mem 0x8000200000-0x80003fffff 64bit pref]
> pcieport 0000:00:01.0: PME: Signaling with IRQ 51
> pcieport 0000:00:01.0: AER: enabled with IRQ 51
> pcieport 0000:00:01.0: pciehp: Slot #0 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep+
> pcieport 0000:00:04.0: PME: Signaling with IRQ 52
> pcieport 0000:00:04.0: AER: enabled with IRQ 52
> pcieport 0000:00:04.0: pciehp: Slot #2 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep+
> pcieport 0000:03:00.0: pciehp: Slot #3 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise+ Interlock+ NoCompl- IbPresDis- LLActRep-
> virtio-pci 0000:00:02.0: enabling device (0000 -> 0003)
> virtio-pci 0000:00:03.0: enabling device (0000 -> 0003)
> 
> All suggestions of things to test and other useful info to provide welcome.
> 
>>  drivers/pci/setup-bus.c | 62 ++++++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 61 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
>> index 3b981da0fb4e..df9fc974b313 100644
>> --- a/drivers/pci/setup-bus.c
>> +++ b/drivers/pci/setup-bus.c
>> @@ -1768,7 +1768,10 @@ static void adjust_bridge_window(struct pci_dev *bridge, struct resource *res,
>>  	}
>>  
>>  	res->end = res->start + new_size - 1;
>> -	remove_from_list(add_list, res);
>> +
>> +	/* If the resource is part of the add_list remove it now */
>> +	if (add_list)
>> +		remove_from_list(add_list, res);
>>  }
>>  
>>  static void pci_bus_distribute_available_resources(struct pci_bus *bus,
>> @@ -1923,6 +1926,8 @@ static void pci_bridge_distribute_available_resources(struct pci_dev *bridge,
>>  	if (!bridge->is_hotplug_bridge)
>>  		return;
>>  
>> +	pci_dbg(bridge, "distributing available resources\n");
>> +
>>  	/* Take the initial extra resources from the hotplug port */
>>  	available_io = bridge->resource[PCI_BRIDGE_IO_WINDOW];
>>  	available_mmio = bridge->resource[PCI_BRIDGE_MEM_WINDOW];
>> @@ -1934,6 +1939,59 @@ static void pci_bridge_distribute_available_resources(struct pci_dev *bridge,
>>  					       available_mmio_pref);
>>  }
>>  
>> +static bool pci_bridge_resources_not_assigned(struct pci_dev *dev)
>> +{
>> +	const struct resource *r;
>> +
>> +	/*
>> +	 * Check the child device's resources and if they are not yet
>> +	 * assigned it means we are configuring them (not the boot
>> +	 * firmware) so we should be able to extend the upstream
>> +	 * bridge's (that's the hotplug downstream PCIe port) resources
>> +	 * in the same way we do with the normal hotplug case.
>> +	 */
>> +	r = &dev->resource[PCI_BRIDGE_IO_WINDOW];
>> +	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
>> +		return false;
>> +	r = &dev->resource[PCI_BRIDGE_MEM_WINDOW];
>> +	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
>> +		return false;
>> +	r = &dev->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
>> +	if (!r->flags || !(r->flags & IORESOURCE_STARTALIGN))
>> +		return false;
>> +
>> +	return true;
>> +}
>> +
>> +static void pci_root_bus_distribute_available_resources(struct pci_bus *bus,
>> +							struct list_head *add_list)
>> +{
>> +	struct pci_dev *dev, *bridge = bus->self;
>> +
>> +	for_each_pci_bridge(dev, bus) {
>> +		struct pci_bus *b;
>> +
>> +		b = dev->subordinate;
>> +		if (!b)
>> +			continue;
>> +
>> +		/*
>> +		 * Need to check "bridge" here too because it is NULL
>> +		 * in case of root bus.
>> +		 */
>> +		if (bridge && pci_bridge_resources_not_assigned(dev)) {
>> +			pci_bridge_distribute_available_resources(bridge, add_list);
>> +			/*
>> +			 * There is only PCIe upstream port on the bus
>> +			 * so we don't need to go futher.
>> +			 */
>> +			return;
>> +		}
>> +
>> +		pci_root_bus_distribute_available_resources(b, add_list);
>> +	}
>> +}
>> +
>>  /*
>>   * First try will not touch PCI bridge res.
>>   * Second and later try will clear small leaf bridge res.
>> @@ -1973,6 +2031,8 @@ void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus)
>>  	 */
>>  	__pci_bus_size_bridges(bus, add_list);
>>  
>> +	pci_root_bus_distribute_available_resources(bus, add_list);
>> +
>>  	/* Depth last, allocate resources and update the hardware. */
>>  	__pci_bus_assign_resources(bus, add_list, &fail_head);
>>  	if (add_list)
> 
> 
> 

[PATCH v2 5/6] PCI: Fix whitespace and indentation

[Mika Westerberg]

Drop two empty lines from pci_scan_child_bus_extend() and correct
indentation in pci_bridge_distribute_available_resources() to better
follow the kernel coding style.

No functional impact.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/pci/probe.c     | 2 --
 drivers/pci/setup-bus.c | 2 +-
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 86130926a74f..8f25deb6b763 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2930,7 +2930,6 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus,
 		unsigned int buses = 0;
 
 		if (!hotplug_bridges && normal_bridges == 1) {
-
 			/*
 			 * There is only one bridge on the bus (upstream
 			 * port) so it gets all available buses which it
@@ -2939,7 +2938,6 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus,
 			 */
 			buses = available_buses;
 		} else if (dev->is_hotplug_bridge) {
-
 			/*
 			 * Distribute the extra buses between hotplug
 			 * bridges if any.
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index df9fc974b313..dc6a30ee6edf 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1919,7 +1919,7 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
 }
 
 static void pci_bridge_distribute_available_resources(struct pci_dev *bridge,
-						     struct list_head *add_list)
+						      struct list_head *add_list)
 {
 	struct resource available_io, available_mmio, available_mmio_pref;
 
-- 
2.35.1

[PATCH v2 6/6] PCI: Fix typo in pci_scan_child_bus_extend()

[Mika Westerberg]

Should be 'if' not 'of'. Fix this.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/pci/probe.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8f25deb6b763..b66fa42c4b1f 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2956,7 +2956,7 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus,
 	/*
 	 * Make sure a hotplug bridge has at least the minimum requested
 	 * number of buses but allow it to grow up to the maximum available
-	 * bus number of there is room.
+	 * bus number if there is room.
 	 */
 	if (bus->self && bus->self->is_hotplug_bridge) {
 		used_buses = max_t(unsigned int, available_buses,
-- 
2.35.1

Re: [PATCH v2 0/6] PCI: Allow for future resource expansion on initial root bus scan

[Bjorn Helgaas]

On Mon, Sep 05, 2022 at 11:02:26AM +0300, Mika Westerberg wrote:
> Hi,
> 
> The series works around an issue found on some Dell systems where
> booting with Thunderbolt/USB4 devices connected the BIOS leaves some of
> the PCIe devices unconfigured. If the connected devices that are not
> configured have PCIe hotplug ports as well the initial root bus scan
> only reserves the minimum amount of resources to them making any
> expansion happening later impossible.
> 
> We do already distribute the "spare" resources between hotplug ports on
> hot-add but we have not done that upon the initial scan. The first four
> patches make the initial root bus scan path to do the same.
> 
> The additional patches are just a small cleanups that can be applied
> separately too.
> 
> The related bug: https://bugzilla.kernel.org/show_bug.cgi?id=216000.
> 
> The previous version of the patch series can be found here:
> 
>   https://lore.kernel.org/linux-pci/20220816100740.68667-1-mika.westerberg@linux.intel.com/
> 
> Changes from the previous version:
> 
>   * Split patch 3 into two: move and then the actual fix as suggested by
>     Andy.
>   * Fold the two whitespace fixes into one patch.
>   * Added tags from Chris and Andy.
> 
> Mika Westerberg (6):
>   PCI: Fix used_buses calculation in pci_scan_child_bus_extend()
>   PCI: Pass available buses also when the bridge is already configured
>   PCI: Move pci_assign_unassigned_root_bus_resources()
>   PCI: Distribute available resources for root buses too
>   PCI: Fix whitespace and indentation
>   PCI: Fix typo in pci_scan_child_bus_extend()
> 
>  drivers/pci/probe.c     |  13 +-
>  drivers/pci/setup-bus.c | 290 ++++++++++++++++++++++++----------------
>  2 files changed, 181 insertions(+), 122 deletions(-)

Applied to pci/resource for v6.1, thanks, Mika!