Xen dom0 "interrupt storm detected on "irq16:"; throttling interrupt source"

[Roger Pau Monné]

Hello,

El 15/05/15 a les 14.22, Eggert, Lars ha escrit:
> On 2015-5-15, at 13:59, Roger Pau Monné <roger.pau at citrix.com> wrote:
>> Can you provide the bootlog with the patch applied?
> 
> Below.

That's weird, AFAICT the patch I've send you should force isci to use 
the legacy interrupt, but it seems it still tries to use MSI-X.

I've attached another patch that will force isci to print some 
messages, can you try that?

It should be applied on a clean tree, since it also contains the change 
to xen_msi.c I've send you before, and of course you should not set 
hw.isci.force_legacy_interrupts when testing it.

>> Also, can you try if there's any difference when setting:
>> hw.isci.force_legacy_interrupts=1
>> on /boot/loader.conf?
> 
> That seems to elimintate the storm. The isci line is now simply:
> 
> isci0: <Intel(R) C600 Series Chipset SAS Controller (SATA mode)> port 0x6000-0x60ff mem 0xde07c000-0xde07ffff,0xddc00000-0xddffffff irq 16 at device 0.0 on pci10

Can you confirm the device works properly with 
hw.isci.force_legacy_interrupts=1?

Thanks, Roger.

---
diff --git a/sys/dev/isci/isci_interrupt.c b/sys/dev/isci/isci_interrupt.c
index 52c64f7..f82b9de 100644
--- a/sys/dev/isci/isci_interrupt.c
+++ b/sys/dev/isci/isci_interrupt.c
@@ -137,6 +137,8 @@ isci_interrupt_setup(struct isci_softc *isci)
 
 		isci->num_interrupts = max_msix_messages;
 		pci_alloc_msix(isci->device, &isci->num_interrupts);
+		printf("ISCI: isci->num_interrupts: %u max_msix_messages: %u\n",
+		     isci->num_interrupts, max_msix_messages);
 		if (isci->num_interrupts == max_msix_messages)
 			use_msix = TRUE;
 	}
diff --git a/sys/x86/xen/xen_msi.c b/sys/x86/xen/xen_msi.c
index 0f678b1..21b542a 100644
--- a/sys/x86/xen/xen_msi.c
+++ b/sys/x86/xen/xen_msi.c
@@ -114,6 +114,7 @@ int
 xen_msix_alloc(device_t dev, int *irq)
 {
 
+	*irq = 0;
 	return (ENXIO);
 }