From mboxrd@z Thu Jan  1 00:00:00 1970
From: Neil Turton <nturton@solarflare.com>
Subject: Re: [PATCH 0/5] Add MSI support to XEN
Date: Wed, 02 Apr 2008 15:55:50 +0100
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To: "Shan, Haitao" <haitao.shan@intel.com>
Cc: Keir Fraser <Keir.Fraser@cl.cam.ac.uk>, xen-devel <xen-devel@lists.xensource.com>, "Li,
	Xin B" <xin.b.li@intel.com>, "Tian, Kevin" <kevin.tian@intel.com>, "Jiang,
	Yunhong" <yunhong.jiang@intel.com>
List-Id: xen-devel@lists.xenproject.org

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]