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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: 3cf485540e ("ACPI: Add driver for the VIOT table")
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reported-by: Jin Liu <jinl@redhat.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Tested-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Eric Auger 2022-06-30 11:40:59 +02:00 committed by Rafael J. Wysocki
parent 88084a3df1
commit 3dcb861dbc
3 changed files with 23 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/acpi/bus.c
View File

@ -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();

26
drivers/acpi/viot.c
View File

@ -248,6 +248,26 @@ err_free:
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);
}

2
include/linux/acpi_viot.h
View File

@ -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)
{