Re: [Xen-devel] Re: [PATCH] xen: drop anti-dependency on X86_VISWS
On 04/09/2011 03:34 AM, Ian Campbell wrote: >>> Actually it does - see the "#ifndef CONFIG_X86_CMPXCHG" section >>> in asm/cmpxchg_32.h. >> Hm, OK. Still, I'm happiest with that dependency in case someone >> knobbles the cpu to exclude cmpxchg and breaks things. > Dropping the TSC patch is sensible though? You mean dropping the TSC dependency? Yes, I think so. J ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization
Re: [Xen-devel] Re: [PATCH] xen: drop anti-dependency on X86_VISWS
On Fri, 2011-04-08 at 11:24 -0700, Jeremy Fitzhardinge wrote: > On 04/08/2011 08:42 AM, Jan Beulich wrote: > On 08.04.11 at 17:25, Jeremy Fitzhardinge wrote: > >> On 04/07/2011 11:38 PM, Ian Campbell wrote: > >>> Is there any downside to this patch (is X86_CMPXCHG in the same sort of > >>> boat?) > >> Only if we don't use cmpxchg in shared memory with other domains or the > >> hypervisor. (I don't think it will dynamically switch between real and > >> emulated cmpxchg depending on availability.) We do use cmpxchg in the grant table code at least (actually, sync_cmpxchng in that case). > > Actually it does - see the "#ifndef CONFIG_X86_CMPXCHG" section > > in asm/cmpxchg_32.h. > > Hm, OK. Still, I'm happiest with that dependency in case someone > knobbles the cpu to exclude cmpxchg and breaks things. Dropping the TSC patch is sensible though? Ian. ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization
Re: [Xen-devel] Re: [PATCH] xen: drop anti-dependency on X86_VISWS
On 04/08/2011 08:42 AM, Jan Beulich wrote: On 08.04.11 at 17:25, Jeremy Fitzhardinge wrote: >> On 04/07/2011 11:38 PM, Ian Campbell wrote: >>> Is there any downside to this patch (is X86_CMPXCHG in the same sort of >>> boat?) >> Only if we don't use cmpxchg in shared memory with other domains or the >> hypervisor. (I don't think it will dynamically switch between real and >> emulated cmpxchg depending on availability.) > Actually it does - see the "#ifndef CONFIG_X86_CMPXCHG" section > in asm/cmpxchg_32.h. Hm, OK. Still, I'm happiest with that dependency in case someone knobbles the cpu to exclude cmpxchg and breaks things. J ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization
[Xen-devel] Re: [PATCH] xen: drop anti-dependency on X86_VISWS
>>> On 08.04.11 at 17:25, Jeremy Fitzhardinge wrote: > On 04/07/2011 11:38 PM, Ian Campbell wrote: >> Is there any downside to this patch (is X86_CMPXCHG in the same sort of >> boat?) > > Only if we don't use cmpxchg in shared memory with other domains or the > hypervisor. (I don't think it will dynamically switch between real and > emulated cmpxchg depending on availability.) Actually it does - see the "#ifndef CONFIG_X86_CMPXCHG" section in asm/cmpxchg_32.h. Jan ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization
