From c24bbe45965da4cf31203ce17cc274a0eec663a4 Mon Sep 17 00:00:00 2001 From: Eric Auger Date: Thu, 30 Jun 2022 11:40:59 +0200 Subject: [PATCH] ACPI: VIOT: Fix ACS setup [ 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 Reported-by: Jin Liu Reviewed-by: Jean-Philippe Brucker Tested-by: Jean-Philippe Brucker Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- 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 fc9bb06..7774b60 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -1340,6 +1340,7 @@ static int __init acpi_init(void) pci_mmcfg_late_init(); acpi_iort_init(); + acpi_viot_early_init(); acpi_hest_init(); ghes_init(); acpi_scan_init(); diff --git a/drivers/acpi/viot.c b/drivers/acpi/viot.c index d225632..647f11c 100644 --- a/drivers/acpi/viot.c +++ b/drivers/acpi/viot.c @@ -249,6 +249,26 @@ err_free: } /** + * 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 * * Parse the VIOT table, prepare the list of endpoints to be used during DMA @@ -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 1eb8ee5..a5a1224 100644 --- a/include/linux/acpi_viot.h +++ b/include/linux/acpi_viot.h @@ -6,9 +6,11 @@ #include #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) { -- 2.7.4