diff options
| author | Alex Williamson <alex.williamson@redhat.com> | 2025-01-20 11:21:59 -0700 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2025-01-23 11:05:20 -0600 |
| commit | 4453f360862e5d9f0807941d613162c3f7a36559 (patch) | |
| tree | 97a4add01f845f4d78d262f562e789ba8593e852 /drivers/pci/pci.h | |
| parent | 40384c840ea1944d7c5a392e8975ed088ecf0b37 (diff) | |
PCI: Batch BAR sizing operations
Toggling memory enable is free on bare metal, but potentially expensive
in virtualized environments as the device MMIO spaces are added and
removed from the VM address space, including DMA mapping of those spaces
through the IOMMU where peer-to-peer is supported. Currently memory
decode is disabled around sizing each individual BAR, even for SR-IOV
BARs while VF Enable is cleared.
This can be better optimized for virtual environments by sizing a set
of BARs at once, stashing the resulting mask into an array, while only
toggling memory enable once. This also naturally improves the SR-IOV
path as the caller becomes responsible for any necessary decode disables
while sizing BARs, therefore SR-IOV BARs are sized relying only on the
VF Enable rather than toggling the PF memory enable in the command
register.
Link: https://lore.kernel.org/r/20250120182202.1878581-1-alex.williamson@redhat.com
Reported-by: Mitchell Augustin <mitchell.augustin@canonical.com>
Link: https://lore.kernel.org/r/CAHTA-uYp07FgM6T1OZQKqAdSA5JrZo0ReNEyZgQZub4mDRrV5w@mail.gmail.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Mitchell Augustin <mitchell.augustin@canonical.com>
Reviewed-by: Mitchell Augustin <mitchell.augustin@canonical.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Diffstat (limited to 'drivers/pci/pci.h')
| -rw-r--r-- | drivers/pci/pci.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 2e40fc63ba31..6f27651c2a70 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -315,8 +315,10 @@ bool pci_bus_generic_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *pl, int pci_idt_bus_quirk(struct pci_bus *bus, int devfn, u32 *pl, int rrs_timeout); int pci_setup_device(struct pci_dev *dev); +void __pci_size_stdbars(struct pci_dev *dev, int count, + unsigned int pos, u32 *sizes); int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, - struct resource *res, unsigned int reg); + struct resource *res, unsigned int reg, u32 *sizes); void pci_configure_ari(struct pci_dev *dev); void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head); |