[PATCH v4 1/3] PCI/IOV: Mark VFs as not implementing MSE bit

Matthew Rosato
2020-09-02T19:46:57Z

Per the PCIe spec, VFs cannot implement the MSE bit
AKA PCI_COMMAND_MEMORY, and it must be hard-wired to 0.
Use a dev_flags bit to signify this requirement.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
drivers/pci/iov.c | 1 +
include/linux/pci.h | 2 ++
2 files changed, 3 insertions(+)

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index b37e08c..2bec77c 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -180,6 +180,7 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id)
virtfn->device = iov->vf_device;
virtfn->is_virtfn = 1;
virtfn->physfn = pci_dev_get(dev);
+ virtfn->dev_flags |= PCI_DEV_FLAGS_FORCE_COMMAND_MEM;

if (id == 0)
pci_read_vf_config_common(virtfn);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8355306..9316cce 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -227,6 +227,8 @@ enum pci_dev_flags {
PCI_DEV_FLAGS_NO_FLR_RESET = (__force pci_dev_flags_t) (1 << 10),
/* Don't use Relaxed Ordering for TLPs directed at this device */
PCI_DEV_FLAGS_NO_RELAXED_ORDERING = (__force pci_dev_flags_t) (1 << 11),
+ /* Device does not implement PCI_COMMAND_MEMORY (e.g. a VF) */
+ PCI_DEV_FLAGS_FORCE_COMMAND_MEM = (__force pci_dev_flags_t) (1 << 12),
};

enum pci_irq_reroute_variant {
--
1.8.3.1