Re: [PATCH 14/23] KVM: PPC: Book3S PR: Delay disabling relocation-on interrupts

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Sat, Aug 31, 2013 at 01:13:07AM +0200, Alexander Graf wrote:
> 
> Oh, sorry to not be more explicit here. I meant the one that actually introduced the relocation-on handling:
> 
>   https://lists.ozlabs.org/pipermail/linuxppc-dev/2012-December/102355.html
> 
> I can't find any trace of that in my inbox, even though it clearly touches KVM PPC code.

True, Ian should have cc'd it to kvm-ppc@vger, I'll mention it to him.

> 
> > 
> >>> +	if (!kvm->arch.relon_disabled) {
> >>> +		if (firmware_has_feature(FW_FEATURE_SET_MODE)) {
> >> 
> >> Is this the same as the endianness setting rtas call? If so, would a PR guest in an HV guest that provides only endianness setting but no relocation-on setting confuse any of this code?
> > 
> > It is the same hcall, but since the interrupts-with-relocation-on
> > function was defined in the first PAPR version that has H_SET_MODE,
> > we shouldn't ever hit that situation.  In any case, if we did happen
> > to run under a (non PAPR-compliant) hypervisor that implemented
> > H_SET_MODE but not the relocation-on setting, then we couldn't have
> > enabled relocation-on interrupts in the first place, so it wouldn't
> > matter.
> 
> Well, I think Anton's patches do exactly that:
> 
>   https://lists.nongnu.org/archive/html/qemu-ppc/2013-08/msg00253.html
> 
> I really just want to double-check that we're not shooting ourselves in the foot here.

I still think there's no real problem, since there would be no other
way to enable relocation-on interrupts other than H_SET_MODE.  So if
H_SET_MODE can't control that setting, then it must be disabled
already.

However, we should also make sure that H_SET_MODE supports changing
the relocation-on setting when it first goes in.  I'm going to want
that soon anyway since I'm working on POWER8 KVM support at the
moment.

Paul.
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux