PCI: add pci_request_acs
Commit ae21ee65e8bc228416bbcc8a1da01c56a847a60c "PCI: acs p2p upsteram
forwarding enabling" doesn't actually enable ACS.
Add a function to pci core to allow an IOMMU to request that ACS
be enabled. The existing mechanism of using iommu_found() in the pci
core to know when ACS should be enabled doesn't actually work due to
initialization order; iommu has only been detected not initialized.
Have Intel and AMD IOMMUs request ACS, and Xen does as well during early
init of dom0.
Cc: Allen Kay <allen.m.kay@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index e01ca4d..0e98f6b 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -614,8 +614,11 @@
#endif
#ifdef CONFIG_DMAR
if (ret && !no_iommu && !iommu_detected && !swiotlb &&
- !dmar_disabled)
+ !dmar_disabled) {
iommu_detected = 1;
+ /* Make sure ACS will be enabled */
+ pci_request_acs();
+ }
#endif
}
early_acpi_os_unmap_memory(dmar_tbl, dmar_tbl_size);