Commit 3dcb861d authored by Eric Auger's avatar Eric Auger Committed by Rafael J. Wysocki
Browse files

ACPI: VIOT: Fix ACS setup 



Currently acpi_viot_init() gets called after the pci
device has been scanned and pci_enable_acs() has been called.
So pci_request_acs() fails to be taken into account leading
to wrong single iommu group topologies when dealing with
multi-function root ports for instance.

We cannot simply move the acpi_viot_init() earlier, similarly
as the IORT init because the VIOT parsing relies on the pci
scan. However we can detect VIOT is present earlier and in
such a case, request ACS. Introduce a new acpi_viot_early_init()
routine that allows to call pci_request_acs() before the scan.

While at it, guard the call to pci_request_acs() with #ifdef
CONFIG_PCI.

Fixes: 3cf48554 ("ACPI: Add driver for the VIOT table")
Signed-off-by: default avatarEric Auger <eric.auger@redhat.com>
Reported-by: default avatarJin Liu <jinl@redhat.com>
Reviewed-by: default avatarJean-Philippe Brucker <jean-philippe@linaro.org>
Tested-by: default avatarJean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 88084a3d

drivers/acpi/bus.c

+1 −0
Original line number Diff line number Diff line
@@ -1400,6 +1400,7 @@ static int __init acpi_init(void) 


	pci_mmcfg_late_init();

	acpi_iort_init();

	acpi_viot_early_init();

	acpi_hest_init();

	acpi_ghes_init();

	acpi_scan_init();

drivers/acpi/viot.c

+20 −6
Original line number Diff line number Diff line
@@ -248,6 +248,26 @@ static int __init viot_parse_node(const struct acpi_viot_header *hdr) 
	return ret;

}



/**

 * acpi_viot_early_init - Test the presence of VIOT and enable ACS

 *

 * If the VIOT does exist, ACS must be enabled. This cannot be

 * done in acpi_viot_init() which is called after the bus scan

 */

void __init acpi_viot_early_init(void)

{

#ifdef CONFIG_PCI

	acpi_status status;

	struct acpi_table_header *hdr;



	status = acpi_get_table(ACPI_SIG_VIOT, 0, &hdr);

	if (ACPI_FAILURE(status))

		return;

	pci_request_acs();

	acpi_put_table(hdr);

#endif

}



/**

 * acpi_viot_init - Parse the VIOT table

 *
@@ -319,12 +339,6 @@ static int viot_pci_dev_iommu_init(struct pci_dev *pdev, u16 dev_id, void *data) 
			epid = ((domain_nr - ep->segment_start) << 16) +

				dev_id - ep->bdf_start + ep->endpoint_id;



			/*

			 * If we found a PCI range managed by the viommu, we're

			 * the one that has to request ACS.

			 */

			pci_request_acs();



			return viot_dev_iommu_init(&pdev->dev, ep->viommu,

						   epid);

		}

include/linux/acpi_viot.h

+2 −0
Original line number Diff line number Diff line
@@ -6,9 +6,11 @@ 
#include <linux/acpi.h>



#ifdef CONFIG_ACPI_VIOT

void __init acpi_viot_early_init(void);

void __init acpi_viot_init(void);

int viot_iommu_configure(struct device *dev);

#else

static inline void acpi_viot_early_init(void) {}

static inline void acpi_viot_init(void) {}

static inline int viot_iommu_configure(struct device *dev)

{