genirq/msi: Activate Multi-MSI early when MSI_FLAG_ACTIVATE_EARLY is set

commit 4c457e8cb75eda91906a4f89fc39bde3f9a43922 upstream.

When MSI_FLAG_ACTIVATE_EARLY is set (which is the case for PCI),
__msi_domain_alloc_irqs() performs the activation of the interrupt (which
in the case of PCI results in the endpoint being programmed) as soon as the
interrupt is allocated.

But it appears that this is only done for the first vector, introducing an
inconsistent behaviour for PCI Multi-MSI.

Fix it by iterating over the number of vectors allocated to each MSI
descriptor. This is easily achieved by introducing a new
"for_each_msi_vector" iterator, together with a tiny bit of refactoring.

Fixes: f3b0946d629c ("genirq/msi: Make sure PCI MSIs are activated early")
Reported-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210123122759.1781359-1-maz@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/msi.h b/include/linux/msi.h
index be8ec813dbfb2dda2bfc802db39b77ee2d145b2f..5dd171849a27e140c3ffd6d8b7245bacf20e3d2b 100644 (file)
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -118,6 +118,12 @@ struct msi_desc {
        list_for_each_entry((desc), dev_to_msi_list((dev)), list)
 #define for_each_msi_entry_safe(desc, tmp, dev)        \
        list_for_each_entry_safe((desc), (tmp), dev_to_msi_list((dev)), list)
+#define for_each_msi_vector(desc, __irq, dev)                          \
+       for_each_msi_entry((desc), (dev))                               \
+               if ((desc)->irq)                                        \
+                       for (__irq = (desc)->irq;                       \
+                            __irq < ((desc)->irq + (desc)->nvec_used); \
+                            __irq++)
 
 #ifdef CONFIG_PCI_MSI
 #define first_pci_msi_entry(pdev)      first_msi_entry(&(pdev)->dev)

diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index dc1186ce3ecdb5ff61b7fc0f0cc0d07dca739405..604974f2afb19a5475b8aa5431145d04c8b90b8c 100644 (file)
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -437,22 +437,22 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 
        can_reserve = msi_check_reservation_mode(domain, info, dev);
 
-       for_each_msi_entry(desc, dev) {
-               virq = desc->irq;
-               if (desc->nvec_used == 1)
-                       dev_dbg(dev, "irq %d for MSI\n", virq);
-               else
+       /*
+        * This flag is set by the PCI layer as we need to activate
+        * the MSI entries before the PCI layer enables MSI in the
+        * card. Otherwise the card latches a random msi message.
+        */
+       if (!(info->flags & MSI_FLAG_ACTIVATE_EARLY))
+               goto skip_activate;
+
+       for_each_msi_vector(desc, i, dev) {
+               if (desc->irq == i) {
+                       virq = desc->irq;
                        dev_dbg(dev, "irq [%d-%d] for MSI\n",
                                virq, virq + desc->nvec_used - 1);
-               /*
-                * This flag is set by the PCI layer as we need to activate
-                * the MSI entries before the PCI layer enables MSI in the
-                * card. Otherwise the card latches a random msi message.
-                */
-               if (!(info->flags & MSI_FLAG_ACTIVATE_EARLY))
-                       continue;
+               }
 
-               irq_data = irq_domain_get_irq_data(domain, desc->irq);
+               irq_data = irq_domain_get_irq_data(domain, i);
                if (!can_reserve) {
                        irqd_clr_can_reserve(irq_data);
                        if (domain->flags & IRQ_DOMAIN_MSI_NOMASK_QUIRK)
@@ -463,28 +463,24 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
                        goto cleanup;
        }
 
+skip_activate:
        /*
         * If these interrupts use reservation mode, clear the activated bit
         * so request_irq() will assign the final vector.
         */
        if (can_reserve) {
-               for_each_msi_entry(desc, dev) {
-                       irq_data = irq_domain_get_irq_data(domain, desc->irq);
+               for_each_msi_vector(desc, i, dev) {
+                       irq_data = irq_domain_get_irq_data(domain, i);
                        irqd_clr_activated(irq_data);
                }
        }
        return 0;
 
 cleanup:
-       for_each_msi_entry(desc, dev) {
-               struct irq_data *irqd;
-
-               if (desc->irq == virq)
-                       break;
-
-               irqd = irq_domain_get_irq_data(domain, desc->irq);
-               if (irqd_is_activated(irqd))
-                       irq_domain_deactivate_irq(irqd);
+       for_each_msi_vector(desc, i, dev) {
+               irq_data = irq_domain_get_irq_data(domain, i);
+               if (irqd_is_activated(irq_data))
+                       irq_domain_deactivate_irq(irq_data);
        }
        msi_domain_free_irqs(domain, dev);
        return ret;