On Mon, Apr 30, 2018 at 2:09 PM, Alex Williamson <alex.williamson@xxxxxxxxxx> wrote: > On Mon, 30 Apr 2018 13:44:23 -0400 > Jintack Lim <jintack@xxxxxxxxxxxxxxx> wrote: > >> Add iommu mailing list since this question might be more related to iommu. >> >> On Mon, Apr 30, 2018 at 10:11 AM, Jintack Lim <jintack@xxxxxxxxxxxxxxx> wrote: >> > Hi, >> > >> > I wonder how to check if Vt-d is capable of posted-interrupt? I'm >> > using Intel E5-2630 v3. >> > >> > I was once told that APICv and posted-interrupt capability always come >> > together. But it seems like my cpu support APICv >> > (/sys/module/kvm_intel/parameters/enable_apicv is Y), but >> > posted-interrupt capability is only shipped with the next generation >> > of the cpu (E5-2600 v4, which is Broadwell). >> > >> > What would be an easy way to check this? > > PI support is bit 59 in the capability register which is exposed > through sysfs at /sys/class/iommu/dmar*/intel-iommu/cap so you could do > something like: > > # for i in $(find /sys/class/iommu/dmar* -type l); do echo -n "$i: "; echo $(( ( 0x$(cat $i/intel-iommu/cap) >> 59 ) & 1 )); done > Thanks for a nice solution, Alex. It turns out my cpu doesn't have the PI capability. /sys/class/iommu/dmar0: 0 /sys/class/iommu/dmar1: 0 > I think the relationship between APICv and PI goes the other direction, > if you have PI, you probably have APICv. Having APICv implies nothing > about having PI. Thanks, Yeah, I think that makes sense. Thanks, Jintack > > Alex >
