Re: Hardware support for vt-posted interrupts described in vt-directed-io-spec for assigned devices

bk rakesh
2015-03-20T09:54:41Z

Adding few more information regarding the setup which i had created to
test the vt-d posted interrupts for assigned devices,

Hardware used for evaluating vt-posted interrupts
cpu "E5-2620 v2 @ 2.10GHz" and "S2600CP server board"

I had used kernel-3.18 patched with "KVM-VFIO IRQ forward
control(posted by eric.auger@linaro.org)", "hierarchy irqdomian(posted
by jiang.liu@linux.intel.com)" and "VT-d Posted-Interrupts
support(http://lwn.net/Articles/626050/) and assigned the ixgbe 10G
NIC via vfio passthrough using qemu-kvm, But resulted in the following
dmesg output,

[233783.657187] dmar: DRHD: handling fault status reg 602
[233783.662926] dmar: INTR-REMAP: Request device [[02:00.0] fault index 47
INTR-REMAP:[fault reason 36] Detected reserved fields in the IRTE entry

I had checked the hardware supported for posted interrupt capability
via capability register bit 59 (#define cap_pi_support(c) (((c) >>
59) & 1)), as described in
"http://www.intel.com/content/www/us/en/embedded/technology/virtualization/vt-directed-io-spec.html",
Which resulted as not supported, Can anyone suggest that does this hw
support posted vt-d feature ? if not then which one to use.

Thanks

On Fri, Mar 20, 2015 at 12:49 PM, bk rakesh <rakeshbkrish@gmail.com> wrote:
>
> Hello,
>
> I am using the S2600CP server board with cpu "Intel(R) Xeon(R) CPU
> E5-2620 v2 @ 2.10GHz" which supports for APICv,
>
> Does this hardware support the vt-d posted interrupt feature as described in
> "[v3 00/26] Add VT-d Posted-Interrupts support" and
> https://lkml.org/lkml/2014 /12/3/102 ,
>
> Requesting to get any information about the hardware that supports this feature.
>
> Thanks,
> Rakesh