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/probe.c b/drivers/pci/probe.c
index 2fdffc0..98ffb2d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -10,9 +10,7 @@
#include <linux/module.h>
#include <linux/cpumask.h>
#include <linux/pci-aspm.h>
-#include <linux/iommu.h>
#include <acpi/acpi_hest.h>
-#include <xen/xen.h>
#include "pci.h"
#define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */
@@ -1029,8 +1027,7 @@
pci_iov_init(dev);
/* Enable ACS P2P upstream forwarding */
- if (iommu_found() || xen_initial_domain())
- pci_enable_acs(dev);
+ pci_enable_acs(dev);
}
void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)