linux-kernel - [RFC PATCH 8/9] arm: KVM: timer: move the timer switch into the non-preemptible section

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Date:	Wed, 25 Jun 2014 10:28:49 +0100
From:	Marc Zyngier <marc.zyngier@....com>
To:	kvmarm@...ts.cs.columbia.edu, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Cc:	Will Deacon <will.deacon@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Thomas Gleixner <tglx@...utronix.de>, eric.auger@...aro.org,
	Christoffer Dall <christoffer.dall@...aro.org>
Subject: [RFC PATCH 8/9] arm: KVM: timer: move the timer switch into the non-preemptible section

In order to convert the timer code to the new interrupt save/restore API,
make sure the timer switch is done in a non-premtible section, so that
we save/restore the state on the right CPU.

Signed-off-by: Marc Zyngier <marc.zyngier@....com>
---
 arch/arm/kvm/arm.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index a291e63..92875b2 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -554,9 +554,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 			vcpu_pause(vcpu);
 
 		kvm_vgic_flush_hwstate(vcpu);
-		kvm_timer_flush_hwstate(vcpu);
 
 		local_irq_disable();
+		kvm_timer_flush_hwstate(vcpu);
 
 		/*
 		 * Re-check atomic conditions
@@ -567,8 +567,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		}
 
 		if (ret <= 0 || need_new_vmid_gen(vcpu->kvm)) {
-			local_irq_enable();
 			kvm_timer_sync_hwstate(vcpu);
+			local_irq_enable();
 			kvm_vgic_sync_hwstate(vcpu);
 			continue;
 		}
@@ -586,6 +586,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		vcpu->arch.last_pcpu = smp_processor_id();
 		kvm_guest_exit();
 		trace_kvm_exit(*vcpu_pc(vcpu));
+		kvm_timer_sync_hwstate(vcpu);
+
 		/*
 		 * We may have taken a host interrupt in HYP mode (ie
 		 * while executing the guest). This interrupt is still
@@ -602,7 +604,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		 * Back from guest
 		 *************************************************************/
 
-		kvm_timer_sync_hwstate(vcpu);
 		kvm_vgic_sync_hwstate(vcpu);
 
 		ret = handle_exit(vcpu, run, ret);
-- 
1.8.3.4

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