Commit 5d990b62 authored by Chris Wright's avatar Chris Wright Committed by Jesse Barnes
Browse files

PCI: add pci_request_acs 



Commit ae21ee65 "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: default avatarChris Wright <chrisw@sous-sol.org>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent b26a34aa

arch/x86/kernel/amd_iommu_init.c

+2 −0
Original line number Diff line number Diff line
@@ -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();

	}

}

arch/x86/xen/enlighten.c

+5 −0
Original line number Diff line number Diff line
@@ -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>
@@ -1170,8 +1171,12 @@ 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");



	/* Start the world */

drivers/pci/dmar.c

+4 −1
Original line number Diff line number Diff line
@@ -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);

drivers/pci/pci.c

+13 −0
Original line number Diff line number Diff line
@@ -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;

drivers/pci/probe.c

+1 −4
Original line number Diff line number Diff line
@@ -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 */
@@ -1029,7 +1027,6 @@ 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);

}

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