Messages in this thread Patch in this message | | | Date | Mon, 02 Nov 2020 13:58:12 +0000 | From | Marc Zyngier <> | Subject | Re: Aw: Re: Re: [PATCH] pci: mediatek: fix warning in msi.h |
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On 2020-11-02 11:56, Frank Wunderlich wrote: > looks good on bananapi-r2, no warning, pcie-card and hdd recognized
Thanks for giving it a shot. Still needs a bit of tweaking, as I expect it to break configurations that select CONFIG_PCI_MSI_ARCH_FALLBACKS (we have to assume that MSIs can be handled until we hit the arch-specific stuff).
There is also a small nit in the way we allow userspace to mess with this flag via sysfs, and similar restrictions should probably apply.
Updated patch below.
M.
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index d15c881e2e7e..5bb1306162c7 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -387,10 +387,20 @@ static ssize_t msi_bus_store(struct device *dev, struct device_attribute *attr, return count; }
- if (val) + if (val) { + /* + * If there is no possibility for this bus to deal with + * MSIs, then allowing them to be requested would lead to + * the kernel complaining loudly. In this situation, don't + * let userspace mess things up. + */ + if (!pci_bus_is_msi_capable(subordinate)) + return -EINVAL; + subordinate->bus_flags &= ~PCI_BUS_FLAGS_NO_MSI; - else + } else { subordinate->bus_flags |= PCI_BUS_FLAGS_NO_MSI; + }
dev_info(&subordinate->dev, "MSI/MSI-X %s for future drivers of devices on this bus\n", val ? "allowed" : "disallowed"); diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 4289030b0fff..28861cc6435a 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -871,6 +871,8 @@ static void pci_set_bus_msi_domain(struct pci_bus *bus) d = pci_host_bridge_msi_domain(b);
dev_set_msi_domain(&bus->dev, d); + if (!pci_bus_is_msi_capable(bus)) + bus->bus_flags |= PCI_BUS_FLAGS_NO_MSI; }
static int pci_register_host_bridge(struct pci_host_bridge *bridge) diff --git a/include/linux/pci.h b/include/linux/pci.h index 22207a79762c..6aadb863dff4 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -2333,6 +2333,12 @@ pci_host_bridge_acpi_msi_domain(struct pci_bus *bus) { return NULL; } static inline bool pci_pr3_present(struct pci_dev *pdev) { return false; } #endif
+static inline bool pci_bus_is_msi_capable(struct pci_bus *bus) +{ + return (IS_ENABLED(CONFIG_PCI_MSI_ARCH_FALLBACKS) || + dev_get_msi_domain(&bus->dev)); +} + #ifdef CONFIG_EEH static inline struct eeh_dev *pci_dev_to_eeh_dev(struct pci_dev *pdev) { -- Jazz is not dead. It just smells funny...
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