From: Oliver Upton commit e9b152cb957c ("arm/arm64: kvm: Set vcpu->cpu to -1 on vcpu_put") reset vcpu->cpu in order for the VGIC to determine if there was any vCPU running at the time of access. The VGIC has gone through an entire rewrite since then, and with commit 7d450e282171 ("KVM: arm/arm64: vgic-new: Add userland access to VGIC dist registers") the user accessors just grab all vCPU mutexes instead. Drop this remaining vestige such that kvm_arch_vcpu_load() can properly detect a CPU migration. While at it, rework kvm_reset_vcpu() to do a much more pedantic check that the provided vCPU is actually what's running on the present CPU. Signed-off-by: Oliver Upton Signed-off-by: Akihiko Odaki --- arch/arm64/kvm/arm.c | 1 - arch/arm64/kvm/reset.c | 16 +++++++++++----- 2 files changed, 11 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 29f48f2c63ec..58d0783f254d 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -734,7 +734,6 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) kvm_arm_vmid_clear_active(); vcpu_clear_on_unsupported_cpu(vcpu); - vcpu->cpu = -1; } static void __kvm_arm_vcpu_power_off(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index b963fd975aac..6bfb21f00444 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -190,7 +190,8 @@ static void kvm_vcpu_reset_sve(struct kvm_vcpu *vcpu) void kvm_reset_vcpu(struct kvm_vcpu *vcpu) { struct vcpu_reset_state reset_state; - bool loaded; + struct kvm_vcpu *running; + bool loaded = false; u32 pstate; spin_lock(&vcpu->arch.mp_state_lock); @@ -198,10 +199,16 @@ void kvm_reset_vcpu(struct kvm_vcpu *vcpu) vcpu->arch.reset_state.reset = false; spin_unlock(&vcpu->arch.mp_state_lock); - preempt_disable(); - loaded = (vcpu->cpu != -1); - if (loaded) + guard(preempt)(); + + running = kvm_get_running_vcpu(); + if (running) { + if (KVM_BUG_ON(running != vcpu, vcpu->kvm)) + return; + + loaded = true; kvm_arch_vcpu_put(vcpu); + } if (!kvm_arm_vcpu_sve_finalized(vcpu)) { if (vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE)) @@ -269,7 +276,6 @@ void kvm_reset_vcpu(struct kvm_vcpu *vcpu) if (loaded) kvm_arch_vcpu_load(vcpu, smp_processor_id()); - preempt_enable(); } u32 kvm_get_pa_bits(struct kvm *kvm) -- 2.55.0