> -----Original Message----- > From: kvm-ppc-owner@xxxxxxxxxxxxxxx [mailto:kvm-ppc- > owner@xxxxxxxxxxxxxxx] On Behalf Of Alexander Graf > Sent: Wednesday, May 16, 2012 2:42 PM > To: Bhushan Bharat-R65777 > Cc: kvm-ppc@xxxxxxxxxxxxxxx > Subject: Re: [PATCH] KVM: PPC: Not optimizing MSR_CE and MSR_DE with > paravirt. > > On 05/16/2012 10:42 AM, Bhushan Bharat-R65777 wrote: > > > >> -----Original Message----- > >> From: kvm-ppc-owner@xxxxxxxxxxxxxxx > >> [mailto:kvm-ppc-owner@xxxxxxxxxxxxxxx] On Behalf Of Alexander Graf > >> Sent: Tuesday, May 15, 2012 8:01 PM > >> To: Bhushan Bharat-R65777 > >> Cc: kvm-ppc@xxxxxxxxxxxxxxx; Bhushan Bharat-R65777 > >> Subject: Re: [PATCH] KVM: PPC: Not optimizing MSR_CE and MSR_DE with > paravirt. > >> > >> On 05/15/2012 09:37 AM, Bharat Bhushan wrote: > >>> From: Bhushan Bharat-R65777<R65777@xxxxxxxxxxxxx> > >>> > >>> If there is pending critical or machine check interrupt then guest > >>> would like to capture it when guest enable MSR.CE and MSR_ME > respectively. > >>> Also as mostly MSR_CE and MSR_ME are updated with rfi/rfci/rfmii > >>> which anyway traps so removing the the paravirt optimization for > >>> MSR.CE and MSR.ME. > >> It's only not safe for e500mc and above, right? > > For e500mc and above the paravirt emulation code will not come into > picture, And critical and machine check interrupt will happen only if MSR > have corresponding bits set. So they are already safe. Is not it? > > Yup, though it might be worth documenting the fact with a few #ifdef's, > in case anyone wants to run PR KVM on e500mc ever. > > > Synchronous error report machine checks don't depend on MSR[ME] in case of e500mc. > >> E500v2 and book3s should be > >> fine. > > And with this patch e500v2 will be fine? Not sure of book3s :). > > Well, e500v2 has edge triggered MCs, no? MSR.CE is unsafe however, as > criticals are basically the same as externals. > In case of e500v2 machine check would be reported if MSR[ME], but if MSR[ME] is not set the core would enter a check stop state. Yes, machine checks on e500v2 are edge triggered. Why is MSR[CE] unsafe? -Varun -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
