[PATCH 2/5] KVM: PPC: Book3S HV P9: Fix irq disabling in tick accounting

Nicholas Piggin npiggin at gmail.com
Thu Sep 8 23:25:42 AEST 2022


kvmhv_run_single_vcpu() disables PMIs as well as Linux irqs,
however the tick time accounting code enables and disables irqs and
not PMIs within this region. By chance this might not actually cause
a bug, but it is clearly an incorrect use of the APIs.

Fixes: 2251fbe76395e ("KVM: PPC: Book3S HV P9: Improve mtmsrd scheduling by delaying MSR[EE] disable")
Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 arch/powerpc/kvm/book3s_hv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 014575b31651..f62dfaaf6c39 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4620,7 +4620,7 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64 time_limit,
 
 	context_tracking_guest_exit();
 	if (!vtime_accounting_enabled_this_cpu()) {
-		local_irq_enable();
+		powerpc_local_irq_pmu_restore(flags);
 		/*
 		 * Service IRQs here before vtime_account_guest_exit() so any
 		 * ticks that occurred while running the guest are accounted to
@@ -4629,7 +4629,7 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64 time_limit,
 		 * interrupts here, which has the problem that it accounts
 		 * interrupt processing overhead to the host.
 		 */
-		local_irq_disable();
+		powerpc_local_irq_pmu_save(flags);
 	}
 	vtime_account_guest_exit();
 
-- 
2.37.2



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