[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 1/4] x86/EPT: force re-evaluation of memory type as necessary
At 12:24 +0100 on 03 Apr (1396524290), Jan Beulich wrote: > >>> On 03.04.14 at 12:18, <tim@xxxxxxx> wrote: > > Hi, > > > > This version looks correct to me, but this tristate: > > > > At 13:17 +0000 on 28 Mar (1396009028), Jan Beulich wrote: > >> + p2m_lock(p2m); > >> + > >> + okay = -curr->arch.hvm_vmx.ept_spurious_misconfig; > > > > [...] > > > >> + if ( okay > 0 ) > >> + { > >> + struct vcpu *v; > >> + > >> + for_each_vcpu ( curr->domain, v ) > >> + v->arch.hvm_vmx.ept_spurious_misconfig = 1; > >> + } > >> + curr->arch.hvm_vmx.ept_spurious_misconfig = 0; > >> + ept_sync_domain(p2m); > >> + p2m_unlock(p2m); > >> + > >> + return !!okay; > > > > seems a bit baroque. Can we go for 'bool_t okay = 0' at the top and then > > > > if ( okay ) > > { > > struct vcpu *v; > > > > for_each_vcpu ( curr->domain, v ) > > v->arch.hvm_vmx.ept_spurious_misconfig = 1; > > } > > else > > okay = curr->arch.hvm_vmx.ept_spurious_misconfig; > > curr->arch.hvm_vmx.ept_spurious_misconfig = 0; > > ept_sync_domain(p2m); > > p2m_unlock(p2m); > > > > return okay; > > > > instead? > > Actually, trying this I find that this conflicts with the added use in > patch 2, so I'd prefer to keep it the way it is. Oh. On closer inspection, in patch 2, when you split a superpage you set okay = 0 and break, which should cause this whole function to return 0, killing the guest. Shouldn't that be a 'continue'? And I'm not sure that setting okay = 0 is the right thing to do anyway. I guess what you're looking for is to avoid a false negative if you split the superpage and then don't clear an invalid EMT in the new leaf; but you might have cleared an invalid EMT at a higher level, in which case okay should not be touched; 'continue' will DTRT. Or maybe I'm confused. Time for lunch and I'll stare at it again. :) Tim. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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