diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2017-02-15 22:37:45 +0200 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2017-02-17 21:52:30 +0200 |
| commit | 4bb571d857d973d9308d9fdb1f48d983d6639bd4 (patch) | |
| tree | 54c49f59e558520ae770603ce4d01762b656db00 /hw/pci | |
| parent | ad584d37f2a86b392c25f3f00cc1f1532676c2d1 (diff) | |
pci/pcie: don't assume cap id 0 is reserved
VFIO actually wants to create a capability with ID == 0.
This is done to make guest drivers skip the given capability.
pcie_add_capability then trips up on this capability
when looking for end of capability list.
To support this use-case, it's easy enough to switch to
e.g. 0xffffffff for these comparisons - we can be sure
it will never match a 16-bit capability ID.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'hw/pci')
| -rw-r--r-- | hw/pci/pcie.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c index cbd4bb4f8c..f4dd177bc4 100644 --- a/hw/pci/pcie.c +++ b/hw/pci/pcie.c @@ -610,7 +610,8 @@ bool pcie_cap_is_arifwd_enabled(const PCIDevice *dev) * uint16_t ext_cap_size */ -static uint16_t pcie_find_capability_list(PCIDevice *dev, uint16_t cap_id, +/* Passing a cap_id value > 0xffff will return 0 and put end of list in prev */ +static uint16_t pcie_find_capability_list(PCIDevice *dev, uint32_t cap_id, uint16_t *prev_p) { uint16_t prev = 0; @@ -679,9 +680,11 @@ void pcie_add_capability(PCIDevice *dev, } else { uint16_t prev; - /* 0 is reserved cap id. use internally to find the last capability - in the linked list */ - next = pcie_find_capability_list(dev, 0, &prev); + /* + * 0xffffffff is not a valid cap id (it's a 16 bit field). use + * internally to find the last capability in the linked list. + */ + next = pcie_find_capability_list(dev, 0xffffffff, &prev); assert(prev >= PCI_CONFIG_SPACE_SIZE); assert(next == 0); |