KVM: PPC: Book3S HV: Fix guest time accounting with VIRT_CPU_ACCOUNTING_GEN

commit 61bd0f66ff92d5ce765ff9850fd3cbfec773c560 upstream.

Since commit 8b24e69fc47e ("KVM: PPC: Book3S HV: Close race with testing
for signals on guest entry"), if CONFIG_VIRT_CPU_ACCOUNTING_GEN is set, the
guest time is not accounted to guest time and user time, but instead to
system time.

This is because guest_enter()/guest_exit() are called while interrupts
are disabled and the tick counter cannot be updated between them.

To fix that, move guest_exit() after local_irq_enable(), and as
guest_enter() is called with IRQ disabled, call guest_enter_irqoff()
instead.

Fixes: 8b24e69fc47e ("KVM: PPC: Book3S HV: Close race with testing for signals on guest entry")
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index e094dc9..165aeb6 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -2847,7 +2847,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
         */
        trace_hardirqs_on();
 
-       guest_enter();
+       guest_enter_irqoff();
 
        srcu_idx = srcu_read_lock(&vc->kvm->srcu);
 
@@ -2855,8 +2855,6 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
 
        srcu_read_unlock(&vc->kvm->srcu, srcu_idx);
 
-       guest_exit();
-
        trace_hardirqs_off();
        set_irq_happened(trap);
 
@@ -2890,6 +2888,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
        kvmppc_set_host_core(pcpu);
 
        local_irq_enable();
+       guest_exit();
 
        /* Let secondaries go back to the offline loop */
        for (i = 0; i < controlled_threads; ++i) {