From: Eric Auger eric.auger@redhat.com
[ Upstream commit 3dcb861dbc6ab101838a1548b1efddd00ca3c3ec ]
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: 3cf485540e7b ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/acpi/bus.c | 1 + drivers/acpi/viot.c | 26 ++++++++++++++++++++------ include/linux/acpi_viot.h | 2 ++ 3 files changed, 23 insertions(+), 6 deletions(-)
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index e2db1bdd9dd2..1d36bb684f5c 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -1399,6 +1399,7 @@ 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(); diff --git a/drivers/acpi/viot.c b/drivers/acpi/viot.c index d2256326c73a..647f11cf165d 100644 --- a/drivers/acpi/viot.c +++ b/drivers/acpi/viot.c @@ -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); } diff --git a/include/linux/acpi_viot.h b/include/linux/acpi_viot.h index 1eb8ee5b0e5f..a5a122431563 100644 --- a/include/linux/acpi_viot.h +++ b/include/linux/acpi_viot.h @@ -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) {