@@ -772,18 +772,25 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries,
u16 control;
void __iomem *base;
- /* Ensure MSI-X is disabled while it is set up */
- pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
+ /*
+ * Some devices require MSI-X to be enabled before the MSI-X
+ * registers can be accessed. Mask all the vectors to prevent
+ * interrupts coming in before they're fully set up.
+ */
+ pci_msix_clear_and_set_ctrl(dev, 0, PCI_MSIX_FLAGS_MASKALL |
+ PCI_MSIX_FLAGS_ENABLE);
pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control);
/* Request & Map MSI-X table region */
base = msix_map_region(dev, msix_table_size(control));
- if (!base)
- return -ENOMEM;
+ if (!base) {
+ ret = -ENOMEM;
+ goto out_disable;
+ }
ret = msix_setup_entries(dev, base, entries, nvec, affd);
if (ret)
- return ret;
+ goto out_disable;
ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
if (ret)
@@ -794,14 +801,6 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries,
if (ret)
goto out_free;
- /*
- * Some devices require MSI-X to be enabled before we can touch the
- * MSI-X registers. We need to mask all the vectors to prevent
- * interrupts coming in before they're fully set up.
- */
- pci_msix_clear_and_set_ctrl(dev, 0,
- PCI_MSIX_FLAGS_MASKALL | PCI_MSIX_FLAGS_ENABLE);
-
msix_program_entries(dev, entries);
ret = populate_msi_sysfs(dev);
@@ -836,6 +835,9 @@ out_avail:
out_free:
free_msi_irqs(dev);
+out_disable:
+ pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
+
return ret;
}
The following commit has been merged into the irq/core branch of tip: Commit-ID: 438553958ba19296663c6d6583d208dfb6792830 Gitweb: https://git.kernel.org/tip/438553958ba19296663c6d6583d208dfb6792830 Author: Thomas Gleixner <tglx@linutronix.de> AuthorDate: Thu, 29 Jul 2021 23:51:40 +02:00 Committer: Thomas Gleixner <tglx@linutronix.de> CommitterDate: Tue, 10 Aug 2021 10:59:20 +02:00 PCI/MSI: Enable and mask MSI-X early The ordering of MSI-X enable in hardware is dysfunctional: 1) MSI-X is disabled in the control register 2) Various setup functions 3) pci_msi_setup_msi_irqs() is invoked which ends up accessing the MSI-X table entries 4) MSI-X is enabled and masked in the control register with the comment that enabling is required for some hardware to access the MSI-X table Step #4 obviously contradicts #3. The history of this is an issue with the NIU hardware. When #4 was introduced the table access actually happened in msix_program_entries() which was invoked after enabling and masking MSI-X. This was changed in commit d71d6432e105 ("PCI/MSI: Kill redundant call of irq_set_msi_desc() for MSI-X interrupts") which removed the table write from msix_program_entries(). Interestingly enough nobody noticed and either NIU still works or it did not get any testing with a kernel 3.19 or later. Nevertheless this is inconsistent and there is no reason why MSI-X can't be enabled and masked in the control register early on, i.e. move step #4 above to step #1. This preserves the NIU workaround and has no side effects on other hardware. Fixes: d71d6432e105 ("PCI/MSI: Kill redundant call of irq_set_msi_desc() for MSI-X interrupts") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Ashok Raj <ashok.raj@intel.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210729222542.344136412@linutronix.de --- drivers/pci/msi.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-)