KVM: PPC: Add PV guest critical sections

When running in hooked code we need a way to disable interrupts without
clobbering any interrupts or exiting out to the hypervisor.

To achieve this, we have an additional critical field in the shared page. If
that field is equal to the r1 register of the guest, it tells the hypervisor
that we're in such a critical section and thus may not receive any interrupts.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/kvm_para.h b/arch/powerpc/include/asm/kvm_para.h
index 556fd59ee0f1..4577e7b6dff1 100644
--- a/arch/powerpc/include/asm/kvm_para.h
+++ b/arch/powerpc/include/asm/kvm_para.h
@@ -24,6 +24,7 @@
 #include <linux/of.h>
 
 struct kvm_vcpu_arch_shared {
+        __u64 critical;         /* Guest may not get interrupts if == r1 */
         __u64 sprg0;
         __u64 sprg1;
         __u64 sprg2;