Messages in this thread | | | Date | Thu, 18 May 2006 14:26:07 -0700 | From | Chris Wright <> | Subject | Re: [RFC PATCH 17/35] Segment register changes for Xen |
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* Zachary Amsden (zach@vmware.com) wrote: > Chris Wright wrote: > >1. We clear FS/GS before changing TLS entries and switching LDT, as > >otherwise the hypervisor will fail to restore thread-local values on > >return to the guest kernel and we take a slow exception path. > > >@@ -647,6 +647,8 @@ struct task_struct fastcall * __switch_t > > */ > > savesegment(fs, prev->fs); > > savesegment(gs, prev->gs); > >+ clearsegment(fs); > >+ clearsegment(gs); > > > > Really not needed. Think about it. You can even speed up Xen.
Please describe how. I'm afraid I'm missing your point, as I don't see the improvement.
> I'm glad the native operation here is a nop, but it should be > hypervisor_clearsegment or xen_clearsegment if you really want to keep it.
Yeah, Andi had similar naming concern. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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