[PATCH] kvm/ppc/booke64: Hard disable interrupts when entering the guest

[Scott Wood]

kvmppc_lazy_ee_enable() was causing interrupts to be soft-enabled
(albeit hard-disabled) in kvmppc_restart_interrupt().  This led to
warnings, and possibly breakage if the interrupt state was later saved
and then restored (leading to interrupts being hard-and-soft enabled
when they should be at least soft-disabled).

Simply removing kvmppc_lazy_ee_enable() leaves interrupts only
soft-disabled when we enter the guest, but they will be hard-disabled
when we exit the guest -- without PACA_IRQ_HARD_DIS ever being set, so
the local_irq_enable() fails to hard-enable.

While we could just set PACA_IRQ_HARD_DIS after an exit to compensate,
instead hard-disable interrupts before entering the guest.  This way,
we won't have to worry about interactions if we take an interrupt
during the guest entry code.  While I don't see any obvious
interactions, it could change in the future (e.g. it would be bad if
the non-hv code were used on 64-bit or if 32-bit guest lazy interrupt
disabling, since the non-hv code changes IVPR among other things).

Signed-off-by: Scott Wood <scottwood at freescale.com>
Cc: Mihai Caraman <mihai.caraman at freescale.com>
---
 arch/powerpc/kvm/booke.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index ecbe908..b216821 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -666,14 +666,14 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
 		return -EINVAL;
 	}
 
-	local_irq_disable();
+	hard_irq_disable();
+	trace_hardirqs_off();
 	s = kvmppc_prepare_to_enter(vcpu);
 	if (s <= 0) {
 		local_irq_enable();
 		ret = s;
 		goto out;
 	}
-	kvmppc_lazy_ee_enable();
 
 	kvm_guest_enter();
 
@@ -1150,13 +1150,12 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 	 * aren't already exiting to userspace for some other reason.
 	 */
 	if (!(r & RESUME_HOST)) {
-		local_irq_disable();
+		hard_irq_disable();
+		trace_hardirqs_off();
 		s = kvmppc_prepare_to_enter(vcpu);
 		if (s <= 0) {
 			local_irq_enable();
 			r = (s << 2) | RESUME_HOST | (r & RESUME_FLAG_NV);
-		} else {
-			kvmppc_lazy_ee_enable();
 		}
 	}
 
-- 
1.7.10.4