[PATCH 5.14 736/849] PCI: Do not enable AtomicOps on VFs

Greg Kroah-Hartman
2021-11-16T01:17:01Z

From: Selvin Xavier <selvin.xavier@broadcom.com>

[ Upstream commit 5ec0a6fcb60ea430f8ee7e0bec22db9b22f856d3 ]

Host crashes when pci_enable_atomic_ops_to_root() is called for VFs with
virtual buses. The virtual buses added to SR-IOV have bus->self set to NULL
and host crashes due to this.

PID: 4481 TASK: ffff89c6941b0000 CPU: 53 COMMAND: "bash"
...
#3 [ffff9a9481713808] oops_end at ffffffffb9025cd6
#4 [ffff9a9481713828] page_fault_oops at ffffffffb906e417
#5 [ffff9a9481713888] exc_page_fault at ffffffffb9a0ad14
#6 [ffff9a94817138b0] asm_exc_page_fault at ffffffffb9c00ace
[exception RIP: pcie_capability_read_dword+28]
RIP: ffffffffb952fd5c RSP: ffff9a9481713960 RFLAGS: 00010246
RAX: 0000000000000001 RBX: ffff89c6b1096000 RCX: 0000000000000000
RDX: ffff9a9481713990 RSI: 0000000000000024 RDI: 0000000000000000
RBP: 0000000000000080 R8: 0000000000000008 R9: ffff89c64341a2f8
R10: 0000000000000002 R11: 0000000000000000 R12: ffff89c648bab000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff89c648bab0c8
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#7 [ffff9a9481713988] pci_enable_atomic_ops_to_root at ffffffffb95359a6
#8 [ffff9a94817139c0] bnxt_qplib_determine_atomics at ffffffffc08c1a33 [bnxt_re]
#9 [ffff9a94817139d0] bnxt_re_dev_init at ffffffffc08ba2d1 [bnxt_re]

Per PCIe r5.0, sec 9.3.5.10, the AtomicOp Requester Enable bit in Device
Control 2 is reserved for VFs. The PF value applies to all associated VFs.

Return -EINVAL if pci_enable_atomic_ops_to_root() is called for a VF.

Link: https://lore.kernel.org/r/1631354585-16597-1-git-send-email-selvin.xavier@broadcom.com
Fixes: 35f5ace5dea4 ("RDMA/bnxt_re: Enable global atomic ops if platform supports")
Fixes: 430a23689dea ("PCI: Add pci_enable_atomic_ops_to_root()")
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Gospodarek <gospo@broadcom.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pci/pci.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index a4eb0c042ca3e..e1de19fad9875 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3709,6 +3709,14 @@ int pci_enable_atomic_ops_to_root(struct pci_dev *dev, u32 cap_mask)
struct pci_dev *bridge;
u32 cap, ctl2;

+ /*
+ * Per PCIe r5.0, sec 9.3.5.10, the AtomicOp Requester Enable bit
+ * in Device Control 2 is reserved in VFs and the PF value applies
+ * to all associated VFs.
+ */
+ if (dev->is_virtfn)
+ return -EINVAL;
+
if (!pci_is_pcie(dev))
return -EINVAL;

--
2.33.0