From 61bd0f66ff92d5ce765ff9850fd3cbfec773c560 Mon Sep 17 00:00:00 2001
From: Laurent Vivier <lvivier@redhat.com>
Date: Fri, 2 Mar 2018 11:51:56 +0100
Subject: [PATCH] KVM: PPC: Book3S HV: Fix guest time accounting with
VIRT_CPU_ACCOUNTING_GEN
References: bsc#1061840
Patch-mainline: v4.16-rc5
Git-commit: 61bd0f66ff92d5ce765ff9850fd3cbfec773c560
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>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/kvm/book3s_hv.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index b4a538b29da5..9cb9448163c4 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -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) {
--
2.13.6