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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-10-02 12:45:08 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-10-02 12:45:08 -0700 |
| commit | d2dbe503fd806082acb0ca79a9d6641822988c2c (patch) | |
| tree | 4aeb0221839d47a8b52718b10db52dd2f4d64f59 | |
| parent | 3b7cab693ba2bab63774bf5b988e8a61b2ef0f32 (diff) | |
| parent | 40cce45b921f7930886bcba43069edc579725457 (diff) | |
Merge tag 'pci-v7.3-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci
Pull PCI fix from Bjorn Helgaas:
- Allow driver to use AtomicOps if already enabled by hypervisor; fixes
regression when Root Port is not visible in a guest (Nikola Prica)
* tag 'pci-v7.3-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci:
PCI: Accept AtomicOps already enabled by the hypervisor
| -rw-r--r-- | drivers/pci/pci.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index b2879a6be5f8..8cc6a89130b5 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3769,8 +3769,21 @@ int pci_enable_atomic_ops_to_root(struct pci_dev *dev, u32 cap_mask) } root = pcie_find_root_port(dev); - if (!root) + if (!root) { + + /* + * A hypervisor may expose a topology with the root port + * not visible to the guest. If the hypervisor has already + * set AtomicOp Requester Enable in the endpoint, we assume + * it has verified support in the root port, so it is safe + * for the driver to use AtomicOps. + */ + pcie_capability_read_dword(dev, PCI_EXP_DEVCTL2, &ctl2); + if (ctl2 & PCI_EXP_DEVCTL2_ATOMIC_REQ) + return 0; + return -EINVAL; + } pcie_capability_read_dword(root, PCI_EXP_DEVCAP2, &cap); if ((cap & cap_mask) != cap_mask) |