forked from rrcarlosr/Jetpack
59 lines
1.9 KiB
Diff
59 lines
1.9 KiB
Diff
|
From 72ccea8afa727f3bba747f6c2d1ca0895e0b2e38 Mon Sep 17 00:00:00 2001
|
||
|
|
From: Josh Cartwright <joshc@ni.com>
|
||
|
|
Date: Thu, 11 Feb 2016 11:54:01 -0600
|
||
|
|
Subject: [PATCH 257/352] KVM: arm/arm64: downgrade preempt_disable()d region
|
||
|
|
to migrate_disable()
|
||
|
|
|
||
|
|
kvm_arch_vcpu_ioctl_run() disables the use of preemption when updating
|
||
|
|
the vgic and timer states to prevent the calling task from migrating to
|
||
|
|
another CPU. It does so to prevent the task from writing to the
|
||
|
|
incorrect per-CPU GIC distributor registers.
|
||
|
|
|
||
|
|
On -rt kernels, it's possible to maintain the same guarantee with the
|
||
|
|
use of migrate_{disable,enable}(), with the added benefit that the
|
||
|
|
migrate-disabled region is preemptible. Update
|
||
|
|
kvm_arch_vcpu_ioctl_run() to do so.
|
||
|
|
|
||
|
|
Cc: Christoffer Dall <christoffer.dall@linaro.org>
|
||
|
|
Reported-by: Manish Jaggi <Manish.Jaggi@caviumnetworks.com>
|
||
|
|
Signed-off-by: Josh Cartwright <joshc@ni.com>
|
||
|
|
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
|
||
|
|
---
|
||
|
|
arch/arm/kvm/arm.c | 6 +++---
|
||
|
|
1 file changed, 3 insertions(+), 3 deletions(-)
|
||
|
|
|
||
|
|
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
|
||
|
|
index a670c70..c45fa92 100644
|
||
|
|
--- a/arch/arm/kvm/arm.c
|
||
|
|
+++ b/arch/arm/kvm/arm.c
|
||
|
|
@@ -619,7 +619,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
|
||
|
|
* involves poking the GIC, which must be done in a
|
||
|
|
* non-preemptible context.
|
||
|
|
*/
|
||
|
|
- preempt_disable();
|
||
|
|
+ migrate_disable();
|
||
|
|
kvm_pmu_flush_hwstate(vcpu);
|
||
|
|
kvm_timer_flush_hwstate(vcpu);
|
||
|
|
kvm_vgic_flush_hwstate(vcpu);
|
||
|
|
@@ -640,7 +640,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
|
||
|
|
kvm_pmu_sync_hwstate(vcpu);
|
||
|
|
kvm_timer_sync_hwstate(vcpu);
|
||
|
|
kvm_vgic_sync_hwstate(vcpu);
|
||
|
|
- preempt_enable();
|
||
|
|
+ migrate_enable();
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
|
||
|
|
@@ -696,7 +696,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
|
||
|
|
|
||
|
|
kvm_vgic_sync_hwstate(vcpu);
|
||
|
|
|
||
|
|
- preempt_enable();
|
||
|
|
+ migrate_enable();
|
||
|
|
|
||
|
|
ret = handle_exit(vcpu, run, ret);
|
||
|
|
}
|
||
|
|
--
|
||
|
|
2.7.4
|
||
|
|
|