[PATCH] KVM: PPC: Book3E 64: Fix IRQs warnings and hangs

[Mihai Caraman]

A change in the generic code highlighted that we were running with IRQs
(soft) enabled on Book3E 64-bit when trying to restart interrupts from
handle_exit(). This is a lesson to configure lockdep often :)

There is no reason to exit guest with soft_enabled == 1, a local_irq_enable()
call will do this for us so get rid of kvmppc_layz_ee() calls. With this fix
we eliminate irqs_disabled() warnings and some guest and host hangs revealed
under stress tests, but guests still exhibit some unresponsiveness.

The unresponsiveness has to do with the fact that arch_local_irq_restore()
does not guarantees to hard enable interrupts. To do so replace exception
function calls like timer_interrupt() with irq_happened flags. The
local_irq_enable() call takes care of replaying them and lets the interrupts
hard enabled.

Signed-off-by: Mihai Caraman <mihai.cara...@freescale.com>
---
 arch/powerpc/kvm/booke.c |    9 +++------
 1 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 1020119..82f155e 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -673,7 +673,6 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct 
kvm_vcpu *vcpu)
                ret = s;
                goto out;
        }
-       kvmppc_lazy_ee_enable();
 
        kvm_guest_enter();
 
@@ -789,16 +788,16 @@ static void kvmppc_restart_interrupt(struct kvm_vcpu 
*vcpu,
        switch (exit_nr) {
        case BOOKE_INTERRUPT_EXTERNAL:
                kvmppc_fill_pt_regs(&regs);
-               do_IRQ(&regs);
+               local_paca->irq_happened |= PACA_IRQ_EE;
                break;
        case BOOKE_INTERRUPT_DECREMENTER:
                kvmppc_fill_pt_regs(&regs);
-               timer_interrupt(&regs);
+               local_paca->irq_happened |= PACA_IRQ_DEC;
                break;
 #if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_BOOK3E_64)
        case BOOKE_INTERRUPT_DOORBELL:
                kvmppc_fill_pt_regs(&regs);
-               doorbell_exception(&regs);
+               local_paca->irq_happened |= PACA_IRQ_DBELL;
                break;
 #endif
        case BOOKE_INTERRUPT_MACHINE_CHECK:
@@ -1148,8 +1147,6 @@ int kvmppc_handle_exit(struct kvm_run *run, struct 
kvm_vcpu *vcpu,
                if (s <= 0) {
                        local_irq_enable();
                        r = (s << 2) | RESUME_HOST | (r & RESUME_FLAG_NV);
-               } else {
-                       kvmppc_lazy_ee_enable();
                }
        }
 
-- 
1.7.4.1


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