Re: [Xen-devel] edge-triggered interrupts in non-ACPI SMP HVM - Keir Fraser - com.xensource.lists.xen-devel

7 messages in com.xensource.lists.xen-develRe: [Xen-devel] edge-triggered interr...

From	Sent On	Attachments
He, Qing	26 Oct 2006 19:19
Keir Fraser	27 Oct 2006 00:49
Keir Fraser	27 Oct 2006 01:10
He, Qing	27 Oct 2006 01:16
He, Qing	27 Oct 2006 01:30
Keir Fraser	27 Oct 2006 02:03
Ross Maxfield	27 Oct 2006 07:52

Subject:	Re: [Xen-devel] edge-triggered interrupts in non-ACPI SMP HVM
From:	Keir Fraser (Keir...@cl.cam.ac.uk)
Date:	10/27/2006 01:10:50 AM
List:	com.xensource.lists.xen-devel

On 27/10/06 9:17 am, "He, Qing" <qing...@intel.com> wrote:

The guest crashed here when insmod platform-pci driver. So that means guest considers the irq as edge triggered. (in fact, if hypervisor does not intentionally crash, the guest is likely to work happily).

Later I checked Linux source, when ACPI is disabled, Linux read MP table to decide irq to I/O APIC binding. This is where it sets the trigger mode of irqs. See arch/i386/kernel/mpparse.c and arch/i386/kernel/io_apic.c

Mp talbe is constructed in hvmloader/mp_table.c, which has only ISA bus...

Yes, but why does the guest set only this PCI device's IRQ to edge-triggered? Why not the rtl8139, for example? Neither is explicitly listed in the MP tables, so where does this differing behaviour come from?

-- Keir