[PATCH v5 13/23] PCI: Make sure bridge windows include their fixed BARs

From: Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
To: <linux-pci@vger.kernel.org>, <linuxppc-dev@lists.ozlabs.org>
Cc: Bjorn Helgaas <helgaas@kernel.org>, <linux@yadro.com>,
	Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
Subject: [PATCH v5 13/23] PCI: Make sure bridge windows include their fixed BARs
Date: Fri, 16 Aug 2019 19:50:51 +0300	[thread overview]
Message-ID: <20190816165101.911-14-s.miroshnichenko@yadro.com> (raw)
In-Reply-To: <20190816165101.911-1-s.miroshnichenko@yadro.com>

When the time comes to select a start address for the bridge window during
the root bus rescan, it should be not just a lowest possible address: this
window must cover all the underlying fixed and immovable BARs. The lowest
address that satisfies this requirement is the .realloc_range field of
struct pci_bus, which is calculated during the preparation to the rescan.

Signed-off-by: Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
---
 drivers/pci/bus.c       |  2 +-
 drivers/pci/setup-res.c | 28 ++++++++++++++++++++++++++--
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 495059d923f7..7aae830751e9 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -192,7 +192,7 @@ static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
 		 * this is an already-configured bridge window, its start
 		 * overrides "min".
 		 */
-		if (avail.start)
+		if (min_used < avail.start)
 			min_used = avail.start;
 
 		max = avail.end;
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 732d18f60f1b..7357bcc12a53 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -248,9 +248,20 @@ static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
 	struct resource *res = dev->resource + resno;
 	resource_size_t min;
 	int ret;
+	resource_size_t start = (resource_size_t)-1;
+	resource_size_t end = 0;
 
 	min = (res->flags & IORESOURCE_IO) ? PCIBIOS_MIN_IO : PCIBIOS_MIN_MEM;
 
+	if (dev->subordinate && resno >= PCI_BRIDGE_RESOURCES) {
+		struct pci_bus *child_bus = dev->subordinate;
+		int b_resno = resno - PCI_BRIDGE_RESOURCES;
+		struct resource *immovable_range = &child_bus->immovable_range[b_resno];
+
+		if (immovable_range->start < immovable_range->end)
+			min = child_bus->realloc_range[b_resno].start;
+	}
+
 	/*
 	 * First, try exact prefetching match.  Even if a 64-bit
 	 * prefetchable bridge window is below 4GB, we can't put a 32-bit
@@ -262,7 +273,7 @@ static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
 				     IORESOURCE_PREFETCH | IORESOURCE_MEM_64,
 				     pcibios_align_resource, dev);
 	if (ret == 0)
-		return 0;
+		goto check_fixed;
 
 	/*
 	 * If the prefetchable window is only 32 bits wide, we can put
@@ -274,7 +285,7 @@ static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
 					     IORESOURCE_PREFETCH,
 					     pcibios_align_resource, dev);
 		if (ret == 0)
-			return 0;
+			goto check_fixed;
 	}
 
 	/*
@@ -287,6 +298,19 @@ static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
 		ret = pci_bus_alloc_resource(bus, res, size, align, min, 0,
 					     pcibios_align_resource, dev);
 
+check_fixed:
+	if (ret == 0 && start < end) {
+		if (res->start > start || res->end < end) {
+			dev_err(&bus->dev, "fixed area 0x%llx-0x%llx for %s doesn't fit in the allocated %pR (0x%llx-0x%llx)",
+				(unsigned long long)start, (unsigned long long)end,
+				dev_name(&dev->dev),
+				res, (unsigned long long)res->start,
+				(unsigned long long)res->end);
+			release_resource(res);
+			return -1;
+		}
+	}
+
 	return ret;
 }
 
-- 
2.21.0

