>>> On 16.03.16 at 18:23, <paul.durr...@citrix.com> wrote: >> From: Jan Beulich [mailto:jbeul...@suse.com] >> Sent: 16 March 2016 16:28 >> >>> On 16.03.16 at 16:02, <paul.durr...@citrix.com> wrote: >> >> From: Konrad Rzeszutek Wilk [mailto:konrad.w...@oracle.com] >> >> Sent: 15 March 2016 23:18 >> >> On Tue, Mar 15, 2016 at 04:14:16PM +0000, Paul Durrant wrote: >> >> > + domain_crash(v->domain); >> >> > + >> >> > + v->arch.hvm_vcpu.viridian.apic_assist.vector = vector; >> >> > + *(uint32_t *)va |= 1u; >> >> >> >> Oh my. What does that do? Why not 0xBADF00D >> >> Is that prescriped in the spec? >> > >> > The LSB is the only bit that has defined functionality. The next 31 bits >> > are >> > reserved and the rest of the page is undefined. >> > >> >> >> >> That looks quite unhealthy to do. >> >> >> > >> > Reading the spec. again I do see that the reserved bits are defined to be >> > zero, so it looks like I can use = rather than |=. >> >> Wouldn't that put at risk forward compatibility? > > The spec just says "Reserved to Zero" so it's hard to know what the right > thing to do is until further bits are defined.
The same as with any other reserved bits, I would say: Leave them alone. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
