On Mon, Apr 24, 2017 at 05:40:07PM -0400, John Ferlan wrote:
On 04/20/2017 08:19 AM, Ján Tomko wrote:Add a new <irqchip> element with a mode attribute. Possible values are off, split or on. https://bugzilla.redhat.com/show_bug.cgi?id=1427005 --- docs/formatdomain.html.in | 10 +++++++ docs/schemas/domaincommon.rng | 16 ++++++++++ src/conf/domain_conf.c | 34 +++++++++++++++++++++- src/conf/domain_conf.h | 12 ++++++++ .../qemuxml2argv-intel-iommu-irqchip.xml | 29 ++++++++++++++++++ .../qemuxml2xmlout-intel-iommu-irqchip.xml | 1 + tests/qemuxml2xmltest.c | 1 + 7 files changed, 102 insertions(+), 1 deletion(-) create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-intel-iommu-irqchip.xml create mode 120000 tests/qemuxml2xmloutdata/qemuxml2xmlout-intel-iommu-irqchip.xml diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index b1e38f0..abf089a 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -1643,6 +1643,7 @@ </kvm> <pvspinlock state='on'/> <gic version='2'/> + <irqchip mode='split'/> </features> ...</pre> @@ -1804,6 +1805,15 @@ for hypervisor to decide. <span class="since">Since 2.1.0</span> </dd> + <dt><code>irqchip</code></dt> + <dd>Tune the in-kernel irqchip. Possible values for the + <code>mode</code> attribute are: + <code>on</code>, <code>split</code> and <code>off</code>. + <code>split</code> is useful for using interrupt remapping + with the <a href="#elementsIommu">IOMMU device</a>.Something that isn't implemented until the subsequent patch, but I'm not against describing this feature a bit more here...
What would you say?
I think most importantly what setting this feature will "do" would be useful. How does someone know they need this?
It is needed if they want interrupt remapping for assigned devices. They can find out from a guide like: http://wiki.qemu.org/Features/VT-d#References or the linked BZ, or from the error message QEMU reports when they try to use interrupt remapping from libvirt without setting this to "split".
And secondarily what would it be required for? What does "on" really do? IOW: What the difference between split and on.
IIUC options other than "split" aren't that useful. Jan
Attachment:
signature.asc
Description: Digital signature
-- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
