ppc: Avoid decrementer related kvm exits
commit55f7d4b09e0bd1f6e5875fe0a5a58852999e4e92
authorDavid Gibson <david@gibson.dropbear.id.au>
Sun, 16 Oct 2011 19:26:17 +0000 (16 19:26 +0000)
committerAlexander Graf <agraf@suse.de>
Sun, 30 Oct 2011 19:03:26 +0000 (30 20:03 +0100)
tree9909c3e93d166e8583424b3ce82ac489f77f0ab3
parentf0ad8c340145b246982885addef1aac183790706
ppc: Avoid decrementer related kvm exits

In __cpu_ppc_store_decr(), we set up a regular timer used to trigger
decrementer interrupts.  This is necessary to implement the decrementer
properly under TCG, but is unnecessary under KVM (true for both Book3S-PR
and Book3S-HV KVM variants), because the kernel handles generating and
delivering decrementer exceptions.

Under kvm, in fact, the timer causes expensive and unnecessary exits from
kvm to qemu.  This patch, therefore, disables setting the timer when kvm
is in use.

Signed-off-by: Anton Blanchard <anton@au1.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
hw/ppc.c