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>
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@ -610,7 +610,8 @@ bool pcie_cap_is_arifwd_enabled(const PCIDevice *dev)
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* uint16_t ext_cap_size
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*/
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static uint16_t pcie_find_capability_list(PCIDevice *dev, uint16_t cap_id,
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/* Passing a cap_id value > 0xffff will return 0 and put end of list in prev */
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static uint16_t pcie_find_capability_list(PCIDevice *dev, uint32_t cap_id,
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uint16_t *prev_p)
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{
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uint16_t prev = 0;
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@ -679,9 +680,11 @@ void pcie_add_capability(PCIDevice *dev,
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} else {
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uint16_t prev;
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/* 0 is reserved cap id. use internally to find the last capability
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in the linked list */
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next = pcie_find_capability_list(dev, 0, &prev);
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/*
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* 0xffffffff is not a valid cap id (it's a 16 bit field). use
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* internally to find the last capability in the linked list.
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*/
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next = pcie_find_capability_list(dev, 0xffffffff, &prev);
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assert(prev >= PCI_CONFIG_SPACE_SIZE);
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assert(next == 0);
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