Re: [PATCH 0/5] Add MSI support to XEN

[Neil Turton <nturton@solarflare.com>]

I tried this patch and MSI seems to work fine with a driver in DOM0.  It
didn't work with MSI-X though because pci_vector_resources returned 8
and I have 10 MSI capable devices in the machine.  I've only got 6
Phys-irq interrupts listed in /proc/interrupts so I'd expect there to be
more vectors free.  I applied the debugging patch below and got the
following output.

diff -r 9bb373519b68 arch/i386/pci/irq-xen.c
--- a/arch/i386/pci/irq-xen.c	Tue Apr 01 14:15:23 2008 +0100
+++ b/arch/i386/pci/irq-xen.c	Wed Apr 02 13:19:05 2008 +0100
@@ -1192,6 +1192,7 @@ int pci_vector_resources(int last, int n
 	int offset = (last % 8);

 	while (next < FIRST_SYSTEM_VECTOR) {
+		printk("next=%d count=%d\n", next, count);
 		next += 8;
 #ifdef CONFIG_X86_64
 		if (next == IA32_SYSCALL_VECTOR)

[pci_vector_resources(176, 1) called]
next=176 count=1
next=184 count=2
next=192 count=3
next=200 count=4
next=208 count=5
next=216 count=6
next=224 count=7
next=232 count=8
[pci_vector_resources returned 8]