Re: [Xen-devel] [PATCH v2] x86/HVM: Avoid cache flush operations during hvm_load

2015-06-02 Thread Jan Beulich
>>> On 02.06.15 at 14:47, wrote: > +void arch_hvm_load_post(struct domain *d) > +{ > +/* Re-enable cache flushes and flush the cache. */ > +this_cpu(memory_type_changed_ignore) = 0; > +memory_type_changed(d); > +} Does this really need to be done unconditionally? I.e. couldn't this be

Re: [Xen-devel] [PATCH v2] x86/HVM: Avoid cache flush operations during hvm_load

2015-06-02 Thread Andrew Cooper
On 02/06/15 13:47, Ross Lagerwall wrote: > An MTRR record is processed for each vCPU during hvm_load. Each MTRR > record sets several mtrrs, each of which flushes the cache on all pCPUs. > This can take some time and trip the watchdog for HVM guests with many > CPUs. > > To fix this, introduce a fl

[Xen-devel] [PATCH v2] x86/HVM: Avoid cache flush operations during hvm_load

2015-06-02 Thread Ross Lagerwall
An MTRR record is processed for each vCPU during hvm_load. Each MTRR record sets several mtrrs, each of which flushes the cache on all pCPUs. This can take some time and trip the watchdog for HVM guests with many CPUs. To fix this, introduce a flag which prevents flushing the cache on x86 while lo