Commit 61bd0f66 authored Mar 02, 2018 by Laurent Vivier Committed by Paul Mackerras Mar 03, 2018

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



Since commit 8b24e69f ("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: 8b24e69f ("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>

parent debd574f

arch/powerpc/kvm/book3s_hv.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -2885,7 +2885,7 @@ 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);

		@@ -2893,8 +2893,6 @@ 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);

		@@ -2937,6 +2935,7 @@ 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) {