| Message ID | 20220630094059.1204283-1-eric.auger@redhat.com |
|---|---|
| State | Accepted |
| Commit | 3dcb861dbc6ab101838a1548b1efddd00ca3c3ec |
| Headers | show |
| Series | [v2] ACPI: VIOT: Fix ACS setup | expand |
On Thu, Jun 30, 2022 at 11:59 AM Jean-Philippe Brucker <jean-philippe@linaro.org> wrote: > > On Thu, Jun 30, 2022 at 11:40:59AM +0200, Eric Auger wrote: > > 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> Applied as 5.20 material, thanks!
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index 86fa61a21826..906ad8153fd9 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -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(); 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) {
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> --- v1 -> v2: - guard acpi_viot_early_init() content with #ifdef CONFIG_PCI - do not call acpi_put_table() if acpi_get_table() failed - change declaration order of acpi_viot_early_init() stub --- drivers/acpi/bus.c | 1 + drivers/acpi/viot.c | 26 ++++++++++++++++++++------ include/linux/acpi_viot.h | 2 ++ 3 files changed, 23 insertions(+), 6 deletions(-)