From 0e69e0dc8dfb2a5d68588c31a15b06b9bd2737a0 Mon Sep 17 00:00:00 2001 From: Nicholas Johnson Date: Wed, 21 Jul 2021 10:29:29 +0800 Subject: [PATCH 2941/2944] PCI: Avoid double hpmemsize MMIO window assignment fix #34916049 commit c13704f5685deb7d6eb21e293233e0901ed77377 upstream Previously, the kernel sometimes assigned more MMIO or MMIO_PREF space than desired. For example, if the user requested 128M of space with "pci=realloc,hpmemsize=128M", we sometimes assigned 256M: pci 0000:06:01.0: BAR 14: assigned [mem 0x90100000-0xa00fffff] = 256M pci 0000:06:04.0: BAR 14: assigned [mem 0xa0200000-0xb01fffff] = 256M With this patch applied: pci 0000:06:01.0: BAR 14: assigned [mem 0x90100000-0x980fffff] = 128M pci 0000:06:04.0: BAR 14: assigned [mem 0x98200000-0xa01fffff] = 128M This happened when in the first pass, the MMIO_PREF succeeded but the MMIO failed. In the next pass, because MMIO_PREF was already assigned, the attempt to assign MMIO_PREF returned an error code instead of success (nothing more to do, already allocated). Hence, the size which was actually allocated, but thought to have failed, was placed in the MMIO window. The bug resulted in the MMIO_PREF being added to the MMIO window, which meant doubling if MMIO_PREF size = MMIO size. With a large MMIO_PREF, the MMIO window would likely fail to be assigned altogether due to lack of 32-bit address space. Change find_free_bus_resource() to do the following: - Return first unassigned resource of the correct type. - If there is none, return first assigned resource of the correct type. - If none of the above, return NULL. Returning an assigned resource of the correct type allows the caller to distinguish between already assigned and no resource of the correct type. Add checks in pbus_size_io() and pbus_size_mem() to return success if resource returned from find_free_bus_resource() is already allocated. This avoids pbus_size_io() and pbus_size_mem() returning error code to __pci_bus_size_bridges() when a resource has been successfully assigned in a previous pass. This fixes the existing behaviour where space for a resource could be reserved multiple times in different parent bridge windows. Link: https://lore.kernel.org/lkml/20190531171216.20532-2-logang@deltatee.com/T/#u Link: https://bugzilla.kernel.org/show_bug.cgi?id=203243 Link: https://lore.kernel.org/r/PS2P216MB075563AA6AD242AA666EDC6A80760@PS2P216MB0755.KORP216.PROD.OUTLOOK.COM Reported-by: Kit Chow Reported-by: Nicholas Johnson Signed-off-by: Nicholas Johnson Signed-off-by: Bjorn Helgaas Reviewed-by: Mika Westerberg Reviewed-by: Logan Gunthorpe Signed-off-by: Guanjun Reviewed-by: Zelin Deng Reviewed-by: Shile Zhang --- drivers/pci/setup-bus.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 38a07d0..7d7cefc 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -792,19 +792,22 @@ static void pci_bridge_check_ranges(struct pci_bus *bus) bus resource of a given type. Note: we intentionally skip the bus resources which have already been assigned (that is, have non-NULL parent resource). */ -static struct resource *find_free_bus_resource(struct pci_bus *bus, - unsigned long type_mask, unsigned long type) +static struct resource *find_bus_resource_of_type(struct pci_bus *bus, + unsigned long type_mask, + unsigned long type) { + struct resource *r, *r_assigned = NULL; int i; - struct resource *r; pci_bus_for_each_resource(bus, r, i) { if (r == &ioport_resource || r == &iomem_resource) continue; if (r && (r->flags & type_mask) == type && !r->parent) return r; + if (r && (r->flags & type_mask) == type && !r_assigned) + r_assigned = r; } - return NULL; + return r_assigned; } static resource_size_t calculate_iosize(resource_size_t size, @@ -893,8 +896,8 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, resource_size_t add_size, struct list_head *realloc_head) { struct pci_dev *dev; - struct resource *b_res = find_free_bus_resource(bus, IORESOURCE_IO, - IORESOURCE_IO); + struct resource *b_res = find_bus_resource_of_type(bus, IORESOURCE_IO, + IORESOURCE_IO); resource_size_t size = 0, size0 = 0, size1 = 0; resource_size_t children_add_size = 0; resource_size_t min_align, align; @@ -902,6 +905,10 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, if (!b_res) return; + /* If resource is already assigned, nothing more to do */ + if (b_res->parent) + return; + min_align = window_alignment(bus, IORESOURCE_IO); list_for_each_entry(dev, &bus->devices, bus_list) { int i; @@ -1007,7 +1014,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, resource_size_t min_align, align, size, size0, size1; resource_size_t aligns[18]; /* Alignments from 1Mb to 128Gb */ int order, max_order; - struct resource *b_res = find_free_bus_resource(bus, + struct resource *b_res = find_bus_resource_of_type(bus, mask | IORESOURCE_PREFETCH, type); resource_size_t children_add_size = 0; resource_size_t children_add_align = 0; @@ -1016,6 +1023,10 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, if (!b_res) return -ENOSPC; + /* If resource is already assigned, nothing more to do */ + if (b_res->parent) + return 0; + memset(aligns, 0, sizeof(aligns)); max_order = 0; size = 0; -- 1.8.3.1