linux/arch/powerpc
Hollis Blanchard df9b856c45 KVM: ppc: use prefetchable mappings for guest memory
Bare metal Linux on 440 can "overmap" RAM in the kernel linear map, so that it
can use large (256MB) mappings even if memory isn't a multiple of 256MB. To
prevent the hardware prefetcher from loading from an invalid physical address
through that mapping, it's marked Guarded.

However, KVM must ensure that all guest mappings are backed by real physical
RAM (since a deliberate access through a guarded mapping could still cause a
machine check). Accordingly, we don't need to make our mappings guarded, so
let's allow prefetching as the designers intended.

Curiously this patch didn't affect performance at all on the quick test I
tried, but it's clearly the right thing to do anyways and may improve other
workloads.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:52:26 +02:00
..
boot Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-12-28 16:54:33 -08:00
configs Merge branch 'next' of master.kernel.org:/pub/scm/linux/kernel/git/jwboyer/powerpc-4xx into next 2008-12-17 11:01:43 +11:00
include/asm KVM: ppc: optimize irq delivery path 2008-12-31 16:52:23 +02:00
kernel KVM: ppc: create struct kvm_vcpu_44x and introduce container_of() accessor 2008-12-31 16:52:22 +02:00
kvm KVM: ppc: use prefetchable mappings for guest memory 2008-12-31 16:52:26 +02:00
lib Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-12-28 16:54:33 -08:00
math-emu powerpc: Add SPE/EFP math emulation for E500v1/v2 processors. 2008-12-03 08:19:16 -06:00
mm Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-12-28 16:54:33 -08:00
oprofile powerpc/cell/OProfile: Fix on-stack array size in activate spu profiling function 2008-10-31 16:13:51 +11:00
platforms Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-12-30 16:10:19 -08:00
sysdev Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-12-28 16:54:33 -08:00
xmon powerpc: Prepare xmon_save_regs for use with kdump 2008-12-23 15:13:28 +11:00
Kconfig Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-12-28 16:54:33 -08:00
Kconfig.debug powerpc: Allow the max stack trace depth to be configured 2008-12-03 20:46:35 +11:00
Makefile powerpc: Remove unncessary SPE related compiler flag 2008-12-03 08:19:10 -06:00