Messages in this thread | | | From | Sheng Yang <> | Subject | Re: [PATCH 2/2 v2] xen: HVM X2APIC support | Date | Thu, 6 Jan 2011 09:20:47 +0800 |
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On Wednesday 05 January 2011 22:56:28 Ian Campbell wrote: > > > @@ -1384,6 +1365,17 @@ static bool __init xen_hvm_platform(void) > > > > > > return true; > > > > > > } > > > > > > +bool xen_hvm_need_lapic(void) > > > +{ > > > + if (xen_pv_domain()) > > > + return false; > > > + if (xen_hvm_domain() && xen_feature(XENFEAT_hvm_pirqs) && > > > + xen_have_vector_callback) > > > + return false; > > > + return (xen_cpuid_base() != 0); > > > +} > > > +EXPORT_SYMBOL_GPL(xen_hvm_need_lapic); > > > + > > Since xen_hvm_domain() is always true if xen_cpuid_base() != 0, isn't > this more obviously written as: > if (!xen_hvm_domain()) > return false;
XEN_HVM_DOMAIN works only when kernel built with CONFIG_XEN. This patch can also support kernel built without CONFIG_XEN but with CONFIG_X86_X2APIC.
> if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback) > return false; > return true; > ? > > Also, checking for the XenVMMXenVMM signature alone seems like a very > broad test for checking the availability of a specific feature, is there > nothing more specific which we could/should be testing?
The CPU flag x2apic is checked when we want to enable x2apic, and only Xen which supported x2apic emulation would show this flag.
-- regards Yang, Sheng
> > Ian.
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