From: Marc Zyngier <maz@kernel.org>
To: Frank Wunderlich <frank-w@public-files.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ryder Lee <ryder.lee@mediatek.com>,
linux-mediatek@lists.infradead.org,
Frank Wunderlich <linux@fw-web.de>,
linux-kernel@vger.kernel.org,
Matthias Brugger <matthias.bgg@gmail.com>,
linux-pci@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>
Subject: Re: Aw: Re: Re: [PATCH] pci: mediatek: fix warning in msi.h
Date: Mon, 02 Nov 2020 13:58:12 +0000 [thread overview]
Message-ID: <336d6588567949029c52ecfbb87660c1@kernel.org> (raw)
In-Reply-To: <trinity-4313623b-1adf-4cc3-8b50-2d0593669995-1604318207058@3c-app-gmx-bap57>
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...
next prev parent reply other threads:[~2020-11-02 13:58 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-31 14:03 [PATCH] pci: mediatek: fix warning in msi.h Frank Wunderlich
2020-10-31 21:49 ` Thomas Gleixner
2020-11-01 9:25 ` Frank Wunderlich
2020-11-01 11:17 ` Thomas Gleixner
2020-11-01 11:43 ` Marc Zyngier
2020-11-01 15:58 ` Aw: " Frank Wunderlich
2020-11-01 17:54 ` Ryder Lee
2020-11-01 18:27 ` Aw: " Frank Wunderlich
2020-11-01 21:47 ` Marc Zyngier
2020-11-01 22:27 ` Thomas Gleixner
2020-11-02 11:30 ` Marc Zyngier
2020-11-02 11:56 ` Aw: " Frank Wunderlich
2020-11-02 13:58 ` Marc Zyngier [this message]
2020-11-02 14:27 ` Aw: " Frank Wunderlich
2020-11-02 16:16 ` Aw: " Thomas Gleixner
2020-11-02 22:18 ` Thomas Gleixner
2020-11-03 9:54 ` Marc Zyngier
2020-11-03 10:16 ` Thomas Gleixner
2020-11-03 10:29 ` Marc Zyngier
2020-11-04 16:49 ` Aw: " Frank Wunderlich
2020-11-04 23:14 ` Thomas Gleixner
2020-11-05 9:20 ` Marc Zyngier
2020-11-05 13:59 ` Aw: " Frank Wunderlich
2020-11-05 23:00 ` Aw: " Thomas Gleixner
2020-11-06 9:43 ` Marc Zyngier
2020-11-21 16:12 ` Aw: " Frank Wunderlich
2021-01-03 13:08 ` Frank Wunderlich
2021-02-02 16:21 ` Frank Wunderlich
2020-11-03 10:31 ` Aw: " Thomas Gleixner
2020-11-03 11:41 ` Marc Zyngier
2020-11-03 14:23 ` Thomas Gleixner
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