On 05.05.13 at 21:33, Andreas Falck <falck.andreas.lists@xxxxxxxxx> wrote:
I tried adding some debugging statements in physdev_map_pirq. I have
attached the physdev.c with my debug statements, a hypervisor log from
testing, and the output of lspci -vv for my three devices.
Since I didn't hear anything from either of you anymore, I went
through the (not very familiar to me) tool stack code again, and
found that qemu and xend/libxl fundamentally disagree about the
model to be used. Qemu wants to allocate PIRQs while xend/libxl
want a 1:1 mapping. Allocating after having created a 1:1 mapping
works by returning the 1:1 mapping as allocation result, so as long
as libxl completes its setup before launching qemu, it would be
obvious why things work there. Consequently I assume that xend
launches qemu quite a bit earlier in the process of creating a new
domain, and the result of an attempt to establish a 1:1 mapping
when a different mapping was already established is dependent on
the specific interrupt numbers (i.e. also explains the observations
one of you made).
Since the tool stack as a whole really ought to use a consistent
model, and since the 1:1 mapping model for non-MSI IRQs seems
quite natural, the below/attached patch takes care of enforcing
a 1:1 mapping in libxc when allocation is being requested by the
caller. Ian, Ian - do you foresee any problem with this?
Please both of you give this a try and let us know of the results
(patch applies cleanly to all of -unstable, 4.2, and 4.1).
Jan
--- a/tools/libxc/xc_physdev.c
+++ b/tools/libxc/xc_physdev.c
@@ -49,7 +49,7 @@ int xc_physdev_map_pirq(xc_interface *xc
map.domid = domid;
map.type = MAP_PIRQ_TYPE_GSI;
map.index = index;
- map.pirq = *pirq;
+ map.pirq = *pirq < 0 ? index : *pirq;
rc = do_physdev_op(xch, PHYSDEVOP_map_pirq, &map, sizeof(map));
--- a/tools/python/xen/xend/server/pciif.py
+++ b/tools/python/xen/xend/server/pciif.py
@@ -340,7 +340,7 @@ class PciController(DevController):
raise VmError(('pci: failed to configure I/O memory on device
'+
'%s - errno=%d')%(dev.name,rc))
- if not self.vm.info.is_hvm() and dev.irq:
+ if dev.irq > 0:
rc = xc.physdev_map_pirq(domid = fe_domid,
index = dev.irq,
pirq = dev.irq)
