From: Igor Druzhinin <igor.druzhinin@citrix.com>
Date: Tue, 28 Sep 2021 14:04:50 +0000 (+0200)
Subject: pci: fix handling of PCI bridges with subordinate bus number 0xff
X-Git-Tag: archive/raspbian/4.16.0+51-g0941d6cb-1+rpi1~2^2~42^2~154
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=9c3b9800e2019c93ab22da69e4a0b22d6fb059ec;p=xen.git

pci: fix handling of PCI bridges with subordinate bus number 0xff

Bus number 0xff is valid according to the PCI spec. Using u8 typed sub_bus
and assigning 0xff to it will result in the following loop getting stuck.

    for ( ; sec_bus <= sub_bus; sec_bus++ ) {...}

Just change its type to unsigned int similarly to what is already done in
dmar_scope_add_buses().

Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
---

diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
index fc4fa2e5c3..d65cda856b 100644
--- a/xen/drivers/passthrough/pci.c
+++ b/xen/drivers/passthrough/pci.c
@@ -363,8 +363,7 @@ static struct pci_dev *alloc_pdev(struct pci_seg *pseg, u8 bus, u8 devfn)
     /* update bus2bridge */
     switch ( pdev->type = pdev_type(pseg->nr, bus, devfn) )
     {
-        u16 cap;
-        u8 sec_bus, sub_bus;
+        unsigned int cap, sec_bus, sub_bus;
 
         case DEV_TYPE_PCIe2PCI_BRIDGE:
         case DEV_TYPE_LEGACY_PCI_BRIDGE:
@@ -431,7 +430,7 @@ static void free_pdev(struct pci_seg *pseg, struct pci_dev *pdev)
     /* update bus2bridge */
     switch ( pdev->type )
     {
-        uint8_t sec_bus, sub_bus;
+        unsigned int sec_bus, sub_bus;
 
         case DEV_TYPE_PCIe2PCI_BRIDGE:
         case DEV_TYPE_LEGACY_PCI_BRIDGE: