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-rw-r--r--arch/arm/include/asm/kvm_host.h2
-rw-r--r--arch/arm64/include/asm/kvm_host.h2
-rw-r--r--virt/kvm/arm/arch_timer.c6
-rw-r--r--virt/kvm/arm/arm.c59
4 files changed, 50 insertions, 19 deletions
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index a9f7d3f47134..6394fb99da7f 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -48,6 +48,8 @@
KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_IRQ_PENDING KVM_ARCH_REQ(1)
+DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
+
u32 *kvm_vcpu_reg(struct kvm_vcpu *vcpu, u8 reg_num, u32 mode);
int __attribute_const__ kvm_target_cpu(void);
int kvm_reset_vcpu(struct kvm_vcpu *vcpu);
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index ea6cb5b24258..e7218cf7df2a 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -47,6 +47,8 @@
KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_IRQ_PENDING KVM_ARCH_REQ(1)
+DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
+
int __attribute_const__ kvm_target_cpu(void);
int kvm_reset_vcpu(struct kvm_vcpu *vcpu);
int kvm_arch_dev_ioctl_check_extension(struct kvm *kvm, long ext);
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index d845d67b7062..cfcd0323deab 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -103,7 +103,8 @@ static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
if (kvm_timer_irq_can_fire(vtimer))
kvm_timer_update_irq(vcpu, true, vtimer);
- if (unlikely(!irqchip_in_kernel(vcpu->kvm)))
+ if (static_branch_unlikely(&userspace_irqchip_in_use) &&
+ unlikely(!irqchip_in_kernel(vcpu->kvm)))
kvm_vtimer_update_mask_user(vcpu);
return IRQ_HANDLED;
@@ -284,7 +285,8 @@ static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level,
trace_kvm_timer_update_irq(vcpu->vcpu_id, timer_ctx->irq.irq,
timer_ctx->irq.level);
- if (likely(irqchip_in_kernel(vcpu->kvm))) {
+ if (!static_branch_unlikely(&userspace_irqchip_in_use) &&
+ likely(irqchip_in_kernel(vcpu->kvm))) {
ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
timer_ctx->irq.irq,
timer_ctx->irq.level,
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 3610e132df8b..59d8e04c19fa 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -74,6 +74,8 @@ static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu)
__this_cpu_write(kvm_arm_running_vcpu, vcpu);
}
+DEFINE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
+
/**
* kvm_arm_get_running_vcpu - get the vcpu running on the current CPU.
* Must be called from non-preemptible context
@@ -302,6 +304,8 @@ void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
{
+ if (vcpu->arch.has_run_once && unlikely(!irqchip_in_kernel(vcpu->kvm)))
+ static_branch_dec(&userspace_irqchip_in_use);
kvm_arch_vcpu_free(vcpu);
}
@@ -522,14 +526,22 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu)
vcpu->arch.has_run_once = true;
- /*
- * Map the VGIC hardware resources before running a vcpu the first
- * time on this VM.
- */
- if (unlikely(irqchip_in_kernel(kvm) && !vgic_ready(kvm))) {
- ret = kvm_vgic_map_resources(kvm);
- if (ret)
- return ret;
+ if (likely(irqchip_in_kernel(kvm))) {
+ /*
+ * Map the VGIC hardware resources before running a vcpu the
+ * first time on this VM.
+ */
+ if (unlikely(!vgic_ready(kvm))) {
+ ret = kvm_vgic_map_resources(kvm);
+ if (ret)
+ return ret;
+ }
+ } else {
+ /*
+ * Tell the rest of the code that there are userspace irqchip
+ * VMs in the wild.
+ */
+ static_branch_inc(&userspace_irqchip_in_use);
}
ret = kvm_timer_enable(vcpu);
@@ -664,19 +676,30 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
kvm_vgic_flush_hwstate(vcpu);
/*
- * If we have a singal pending, or need to notify a userspace
- * irqchip about timer or PMU level changes, then we exit (and
- * update the timer level state in kvm_timer_update_run
- * below).
+ * Exit if we have a signal pending so that we can deliver the
+ * signal to user space.
*/
- if (signal_pending(current) ||
- kvm_timer_should_notify_user(vcpu) ||
- kvm_pmu_should_notify_user(vcpu)) {
+ if (signal_pending(current)) {
ret = -EINTR;
run->exit_reason = KVM_EXIT_INTR;
}
/*
+ * If we're using a userspace irqchip, then check if we need
+ * to tell a userspace irqchip about timer or PMU level
+ * changes and if so, exit to userspace (the actual level
+ * state gets updated in kvm_timer_update_run and
+ * kvm_pmu_update_run below).
+ */
+ if (static_branch_unlikely(&userspace_irqchip_in_use)) {
+ if (kvm_timer_should_notify_user(vcpu) ||
+ kvm_pmu_should_notify_user(vcpu)) {
+ ret = -EINTR;
+ run->exit_reason = KVM_EXIT_INTR;
+ }
+ }
+
+ /*
* Ensure we set mode to IN_GUEST_MODE after we disable
* interrupts and before the final VCPU requests check.
* See the comment in kvm_vcpu_exiting_guest_mode() and
@@ -688,7 +711,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
kvm_request_pending(vcpu)) {
vcpu->mode = OUTSIDE_GUEST_MODE;
kvm_pmu_sync_hwstate(vcpu);
- kvm_timer_sync_hwstate(vcpu);
+ if (static_branch_unlikely(&userspace_irqchip_in_use))
+ kvm_timer_sync_hwstate(vcpu);
kvm_vgic_sync_hwstate(vcpu);
local_irq_enable();
preempt_enable();
@@ -732,7 +756,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
* we don't want vtimer interrupts to race with syncing the
* timer virtual interrupt state.
*/
- kvm_timer_sync_hwstate(vcpu);
+ if (static_branch_unlikely(&userspace_irqchip_in_use))
+ kvm_timer_sync_hwstate(vcpu);
/*
* We may have taken a host interrupt in HYP mode (ie