pci_add_capability() checks whether capabilities overlap, and notifies
its caller so that it can properly handle the case. However, in the
most cases, the capabilities actually never overlap, and the interface
incurred extra error handling code, which is often incorrect or
suboptimal. For such cases, pci_add_capability() can simply abort the
execution if the capabilities actually overlap since it should be a
programming error.
This change handles the other cases: hw/vfio/pci depends on the check to
decide MSI and MSI-X capabilities overlap with another. As they are
quite an exceptional and hw/vfio/pci knows much about PCI capabilities,
adding code specific to the cases to hw/vfio/pci still results in less
code than having error handling code everywhere in total.
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
hw/pci/pci.c | 34 ++++++++++++++++++++++------------
hw/vfio/pci.c | 15 ++++++++++++++-
include/hw/pci/pci.h | 3 +++
3 files changed, 39 insertions(+), 13 deletions(-)
/*
* On success, pci_add_capability() returns a positive value
* that the offset of the pci capability.
@@ -2523,7 +2542,6 @@ int pci_add_capability(PCIDevice *pdev, uint8_t cap_id,
Error **errp)
{
uint8_t *config;
- int i, overlapping_cap;
if (!offset) {
offset = pci_find_space(pdev, size);
@@ -2534,17 +2552,9 @@ int pci_add_capability(PCIDevice *pdev, uint8_t cap_id,
* depends on this check to verify that the device is not broken.
* Should never trigger for emulated devices, but it's helpful
* for debugging these. */
- for (i = offset; i < offset + size; i++) {
- overlapping_cap = pci_find_capability_at_offset(pdev, i);
- if (overlapping_cap) {
- error_setg(errp, "%s:%02x:%02x.%x "
- "Attempt to add PCI capability %x at offset "
- "%x overlaps existing capability %x at offset %x",
- pci_root_bus_path(pdev), pci_dev_bus_num(pdev),
- PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn),
- cap_id, offset, overlapping_cap, i);
- return -EINVAL;
- }
+ pci_check_capability_overlap(pdev, cap_id, offset, size, errp);
+ if (errp) {