diff options
author | Bjorn Helgaas <bhelgaas@google.com> | 2019-01-19 11:35:04 -0600 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-08-21 11:05:29 +0200 |
commit | 54a7a9d75c0727433feb634b1025c84589949e02 (patch) | |
tree | d5f8e5a90f1d41cc73776d295ad2488234ce4dd2 /include | |
parent | dd6dc2fd66824c2fc6bdf07ff44a00a9695636d2 (diff) |
PCI: Probe bridge window attributes once at enumeration-time
commit 51c48b310183ab6ba5419edfc6a8de889cc04521 upstream.
pci_bridge_check_ranges() determines whether a bridge supports the optional
I/O and prefetchable memory windows and sets the flag bits in the bridge
resources. This *could* be done once during enumeration except that the
resource allocation code completely clears the flag bits, e.g., in the
pci_assign_unassigned_bridge_resources() path.
The problem with pci_bridge_check_ranges() in the resource allocation path
is that we may allocate resources after devices have been claimed by
drivers, and pci_bridge_check_ranges() *changes* the window registers to
determine whether they're writable. This may break concurrent accesses to
devices behind the bridge.
Add a new pci_read_bridge_windows() to determine whether a bridge supports
the optional windows, call it once during enumeration, remember the
results, and change pci_bridge_check_ranges() so it doesn't touch the
bridge windows but sets the flag bits based on those remembered results.
Link: https://lore.kernel.org/linux-pci/1506151482-113560-1-git-send-email-wangzhou1@hisilicon.com
Link: https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg02082.html
Reported-by: Yandong Xu <xuyandong2@huawei.com>
Tested-by: Yandong Xu <xuyandong2@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Ofer Hayut <ofer@lightbitslabs.com>
Cc: Roy Shterman <roys@lightbitslabs.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Zhou Wang <wangzhou1@hisilicon.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=208371
Signed-off-by: Dima Stepanov <dimastep@yandex-team.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/pci.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/pci.h b/include/linux/pci.h index b1f297f4b7b0..2517492dd185 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -373,6 +373,9 @@ struct pci_dev { bool match_driver; /* Skip attaching driver */ unsigned int transparent:1; /* Subtractive decode bridge */ + unsigned int io_window:1; /* Bridge has I/O window */ + unsigned int pref_window:1; /* Bridge has pref mem window */ + unsigned int pref_64_window:1; /* Pref mem window is 64-bit */ unsigned int multifunction:1; /* Multi-function device */ unsigned int is_busmaster:1; /* Is busmaster */ |