diff options
| -rw-r--r-- | arch/arm64/include/asm/kvm_host.h | 1 | ||||
| -rw-r--r-- | arch/arm64/kvm/arm.c | 1 | ||||
| -rw-r--r-- | arch/arm64/kvm/vmid.c | 25 |
3 files changed, 24 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 47aeed22e2ad..305ea13c4fd0 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -694,6 +694,7 @@ extern unsigned int kvm_arm_vmid_bits; int kvm_arm_vmid_alloc_init(void); void kvm_arm_vmid_alloc_free(void); void kvm_arm_vmid_update(struct kvm_vmid *kvm_vmid); +void kvm_arm_vmid_clear_active(void); static inline void kvm_arm_pvtime_vcpu_init(struct kvm_vcpu_arch *vcpu_arch) { diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index be2fd84d526b..418014998f18 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -417,6 +417,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) kvm_timer_vcpu_put(vcpu); kvm_vgic_put(vcpu); kvm_vcpu_pmu_restore_host(vcpu); + kvm_arm_vmid_clear_active(); vcpu->cpu = -1; } diff --git a/arch/arm64/kvm/vmid.c b/arch/arm64/kvm/vmid.c index 9aff692b6b7d..8d5f0506fd87 100644 --- a/arch/arm64/kvm/vmid.c +++ b/arch/arm64/kvm/vmid.c @@ -32,6 +32,13 @@ static DEFINE_PER_CPU(u64, reserved_vmids); #define vmid2idx(vmid) ((vmid) & ~VMID_MASK) #define idx2vmid(idx) vmid2idx(idx) +/* + * As vmid #0 is always reserved, we will never allocate one + * as below and can be treated as invalid. This is used to + * set the active_vmids on vCPU schedule out. + */ +#define VMID_ACTIVE_INVALID VMID_FIRST_VERSION + #define vmid_gen_match(vmid) \ (!(((vmid) ^ atomic64_read(&vmid_generation)) >> kvm_arm_vmid_bits)) @@ -122,6 +129,12 @@ set_vmid: return vmid; } +/* Called from vCPU sched out with preemption disabled */ +void kvm_arm_vmid_clear_active(void) +{ + atomic64_set(this_cpu_ptr(&active_vmids), VMID_ACTIVE_INVALID); +} + void kvm_arm_vmid_update(struct kvm_vmid *kvm_vmid) { unsigned long flags; @@ -132,11 +145,17 @@ void kvm_arm_vmid_update(struct kvm_vmid *kvm_vmid) /* * Please refer comments in check_and_switch_context() in * arch/arm64/mm/context.c. + * + * Unlike ASID allocator, we set the active_vmids to + * VMID_ACTIVE_INVALID on vCPU schedule out to avoid + * reserving the VMID space needlessly on rollover. + * Hence explicitly check here for a "!= 0" to + * handle the sync with a concurrent rollover. */ old_active_vmid = atomic64_read(this_cpu_ptr(&active_vmids)); - if (old_active_vmid && vmid_gen_match(vmid) && - atomic64_cmpxchg_relaxed(this_cpu_ptr(&active_vmids), - old_active_vmid, vmid)) + if (old_active_vmid != 0 && vmid_gen_match(vmid) && + 0 != atomic64_cmpxchg_relaxed(this_cpu_ptr(&active_vmids), + old_active_vmid, vmid)) return; raw_spin_lock_irqsave(&cpu_vmid_lock, flags); |