[PATCH v8 13/24] PCI: Make sure bridge windows include their fixed BARs

From: Sergei Miroshnichenko <s.miroshnichenko@yadro.com>
To: <linux-pci@vger.kernel.org>
Cc: "Bjorn Helgaas" <helgaas@kernel.org>,
	"Lukas Wunner" <lukas@wunner.de>, "Stefan Roese" <sr@denx.de>,
	"Andy Lavr" <andy.lavr@gmail.com>,
	"Christian König" <christian.koenig@amd.com>,
	"Ard Biesheuvel" <ardb@kernel.org>,
	"David Laight" <David.Laight@ACULAB.COM>,
	"Rajat Jain" <rajatja@google.com>,
	linux@yadro.com,
	"Sergei Miroshnichenko" <s.miroshnichenko@yadro.com>
Subject: [PATCH v8 13/24] PCI: Make sure bridge windows include their fixed BARs
Date: Mon, 27 Apr 2020 21:23:47 +0300	[thread overview]
Message-ID: <20200427182358.2067702-14-s.miroshnichenko@yadro.com> (raw)
In-Reply-To: <20200427182358.2067702-1-s.miroshnichenko@yadro.com>

When choosing a start address for a bridge window, it should be not just a
lowest possible address: this window must cover every underlying fixed BAR.
The lowest address that satisfies this requirement is the .realloc_range
field of struct pci_bus.

After allocating a bridge window, validate that it covers all its fixed
BARs: this range is put to the .fixed_range field of struct pci_bus.

Signed-off-by: Sergei Miroshnichenko <s.miroshnichenko@yadro.com>
---
 drivers/pci/bus.c       |  2 +-
 drivers/pci/setup-res.c | 29 +++++++++++++++++++++++++++--
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 8e40b3e6da77..a1efa87e31b9 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 51bc69d60791..494eb5a2e98c 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -248,9 +248,21 @@ 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;
+	struct resource *fixed_range = NULL;
 
 	min = (res->flags & IORESOURCE_IO) ? PCIBIOS_MIN_IO : PCIBIOS_MIN_MEM;
 
+	if (pci_can_move_bars && dev->subordinate && resno >= PCI_BRIDGE_RESOURCES) {
+		struct pci_bus *child_bus = dev->subordinate;
+		int win_no = resno - PCI_BRIDGE_RESOURCES;
+
+		fixed_range = &child_bus->fixed_range[win_no];
+		if (pci_fixed_range_valid(fixed_range))
+			min = child_bus->realloc_range[win_no].start;
+		else
+			fixed_range = NULL;
+	}
+
 	/*
 	 * 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 +274,7 @@ 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 +286,7 @@ 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 +299,19 @@ 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 && fixed_range &&
+	    (res->start > fixed_range->start ||
+	     res->end < fixed_range->end)) {
+		dev_err(&bus->dev, "fixed area %pR for %s doesn't fit in the allocated %pR (0x%llx-0x%llx)",
+			fixed_range,
+			dev_name(&dev->dev),
+			res, (unsigned long long)res->start,
+			(unsigned long long)res->end);
+		release_resource(res);
+		return -1;
+	}
+
 	return ret;
 }
 
-- 
2.24.1

