When an interrupt occurs for the guest, it is sometimes necessary
to find out which vcpu was running at that point.
Keep track of which vcpu is being tun in kvm_arch_vcpu_ioctl_run(),
and allow the data to be retrived using either:
- kvm_arm_get_running_vcpu(): returns the vcpu running at this point
on the current CPU. Can only be used in a non-preemptable context.
- kvm_arm_get_running_vcpus(): returns the per-CPU variable holding
the the running vcpus, useable for per-CPU interrupts.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
arch/arm/include/asm/kvm_host.h | 4 ++++
arch/arm/kvm/arm.c | 30 ++++++++++++++++++++++++++++++
2 files changed, 34 insertions(+)
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 778d2af..1ccdfa7 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -190,4 +190,8 @@ static inline int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
{
return 0;
}
+
+struct kvm_vcpu *kvm_arm_get_running_vcpu(void);
+struct kvm_vcpu __percpu **kvm_get_running_vcpus(void);
+
#endif /* __ARM_KVM_HOST_H__ */
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index eeb2296..c809909 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -53,11 +53,38 @@ __asm__(".arch_extension virt");
static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
static struct vfp_hard_struct __percpu *kvm_host_vfp_state;
+/* Per-CPU variable containing the currently running vcpu. */
+static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_arm_running_vcpu);
+
/* The VMID used in the VTTBR */
static atomic64_t kvm_vmid_gen = ATOMIC64_INIT(1);
static u8 kvm_next_vmid;
static DEFINE_SPINLOCK(kvm_vmid_lock);
+static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu)
+{
+ BUG_ON(preemptible());
+ __get_cpu_var(kvm_arm_running_vcpu) = vcpu;
+}
+
+/**
+ * kvm_arm_get_running_vcpu - get the vcpu running on the current CPU.
+ * Must be called from non-preemptible context
+ */
+struct kvm_vcpu *kvm_arm_get_running_vcpu(void)
+{
+ BUG_ON(preemptible());
+ return __get_cpu_var(kvm_arm_running_vcpu);
+}
+
+/**
+ * kvm_arm_get_running_vcpus - get the per-CPU array on currently running vcpus.
+ */
+struct kvm_vcpu __percpu **kvm_get_running_vcpus(void)
+{
+ return &kvm_arm_running_vcpu;
+}
+
int kvm_arch_hardware_enable(void *garbage)
{
return 0;
@@ -286,10 +313,13 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
cpumask_clear_cpu(cpu, &vcpu->arch.require_dcache_flush);
flush_cache_all(); /* We'd really want v7_flush_dcache_all() */
}
+
+ kvm_arm_set_running_vcpu(vcpu);
}
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
+ kvm_arm_set_running_vcpu(NULL);
}
int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
--
1.7.11.4
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