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PCI: add pci_request_acs

Browse source 
Commit ae21ee65e8 "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>
This commit is contained in:
Chris Wright 2009-12-04 12:15:21 -08:00 committed by Jesse Barnes
parent b26a34aa47
commit 5d990b6275
6 changed files with 27 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/x86/kernel/amd_iommu_init.c
View file

@ -1330,6 +1330,8 @@ void __init amd_iommu_detect(void)
gart_iommu_aperture_disabled = 1;
gart_iommu_aperture = 0;
#endif
/* Make sure ACS will be enabled */
pci_request_acs();
}
}

5
arch/x86/xen/enlighten.c
View file

@ -27,6 +27,7 @@
#include <linux/page-flags.h>
#include <linux/highmem.h>
#include <linux/console.h>
#include <linux/pci.h>
#include <xen/xen.h>
#include <xen/interface/xen.h>
@ -1170,7 +1171,11 @@ asmlinkage void __init xen_start_kernel(void)
add_preferred_console("xenboot", 0, NULL);
add_preferred_console("tty", 0, NULL);
add_preferred_console("hvc", 0, NULL);
} else {
/* Make sure ACS will be enabled */
pci_request_acs();
}
xen_raw_console_write("about to get started...\n");

5
drivers/pci/dmar.c
View file

@ -614,8 +614,11 @@ void __init detect_intel_iommu(void)
#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);

13
drivers/pci/pci.c
View file

@ -1550,6 +1550,16 @@ void pci_enable_ari(struct pci_dev *dev)
bridge->ari_enabled = 1;
}
static int pci_acs_enable;
/**
* pci_request_acs - ask for ACS to be enabled if supported
*/
void pci_request_acs(void)
{
pci_acs_enable = 1;
}
/**
* pci_enable_acs - enable ACS if hardware support it
* @dev: the PCI device
@ -1560,6 +1570,9 @@ void pci_enable_acs(struct pci_dev *dev)
u16 cap;
u16 ctrl;
if (!pci_acs_enable)
return;
if (!pci_is_pcie(dev))
return;

5
drivers/pci/probe.c
View file

@ -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 @@ static void pci_init_capabilities(struct pci_dev *dev)
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)

2
include/linux/pci.h
View file

@ -1328,5 +1328,7 @@ static inline bool pci_is_pcie(struct pci_dev *dev)
return !!pci_pcie_cap(dev);
}
void pci_request_acs(void);
#endif /* __KERNEL__ */
#endif /* LINUX_PCI_H */