From mboxrd@z Thu Jan  1 00:00:00 1970
From: Bruce Edge <bruce.edge@gmail.com>
Subject: pv-ops domU not working with MSI interrupts on Nehalem
Date: Mon, 27 Sep 2010 08:52:39 -0700
Message-ID: <AANLkTi=G7CTuVP2=b18JjwFsCb_fvk8hoMWAngYUKB1Y@mail.gmail.com>
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One of our developers who is working on a tachyon driver is
complaining that the pvops domU kernel is not working for these MSI
interrupts.
This is using the current head of xen/2.6.32.x on both a single
Nahelam 920 and a dual E5540. This behavior is consistent with Xen
4.0.1, 4.0.2.rc1-pre and 4.1.

Here are his comments:

- the driver has no problem to enable msi interrupt and request the
interrupt through kernel functions pci_enable_msi & request_irq
- the interrupt does happen. But the interrupt service routine of
tachyon driver doesn't detect any interrupt status related to this
interrupt, which inhibits the tachyon chip from coming on-line. And
there are high count of tachyon interrupt in /proc/interrupts

kaan-18-dpm:~# cat /proc/interrupts | grep TACH
124: =A0 =A0 760415 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =
=A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00
=A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =
=A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00
 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0xen-pirq-pcifront-msi =A0HW_TACHYON
125: =A0 =A0 762234 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =
=A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00
=A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =
=A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00
 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0xen-pirq-pcifront-msi =A0HW_TACHYON
126: =A0 =A0 764180 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =
=A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00
=A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =
=A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00
 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0xen-pirq-pcifront-msi =A0HW_TACHYON
127: =A0 =A0 764164 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =
=A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00
=A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =
=A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A0 =A00
 =A0 =A00 =A0 =A0 =A0 =A0 =A00 =A0xen-pirq-pcifront-msi =A0HW_TACHYON


-Bruce