diff options
| author | Paul Mackerras <paulus@ozlabs.org> | 2018-10-08 16:30:54 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-10-09 16:04:27 +1100 |
| commit | 53655ddd7771f703071ac81cc5823eae509b6653 (patch) | |
| tree | 6e2d612098d8b5114035e352dd3b4d4f0e900a8a /arch/powerpc/kvm/book3s_hv.c | |
| parent | 7854f7545bff69567fc3fcd8831752138b892483 (diff) | |
KVM: PPC: Book3S HV: Call kvmppc_handle_exit_hv() with vcore unlocked
Currently kvmppc_handle_exit_hv() is called with the vcore lock held
because it is called within a for_each_runnable_thread loop.
However, we already unlock the vcore within kvmppc_handle_exit_hv()
under certain circumstances, and this is safe because (a) any vcpus
that become runnable and are added to the runnable set by
kvmppc_run_vcpu() have their vcpu->arch.trap == 0 and can't actually
run in the guest (because the vcore state is VCORE_EXITING), and
(b) for_each_runnable_thread is safe against addition or removal
of vcpus from the runnable set.
Therefore, in order to simplify things for following patches, let's
drop the vcore lock in the for_each_runnable_thread loop, so
kvmppc_handle_exit_hv() gets called without the vcore lock held.
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kvm/book3s_hv.c')
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv.c | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 49a686c1185c..0e17593ee6e3 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -1084,7 +1084,6 @@ static int kvmppc_emulate_doorbell_instr(struct kvm_vcpu *vcpu) return RESUME_GUEST; } -/* Called with vcpu->arch.vcore->lock held */ static int kvmppc_handle_exit_hv(struct kvm_run *run, struct kvm_vcpu *vcpu, struct task_struct *tsk) { @@ -1205,10 +1204,7 @@ static int kvmppc_handle_exit_hv(struct kvm_run *run, struct kvm_vcpu *vcpu, swab32(vcpu->arch.emul_inst) : vcpu->arch.emul_inst; if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) { - /* Need vcore unlocked to call kvmppc_get_last_inst */ - spin_unlock(&vcpu->arch.vcore->lock); r = kvmppc_emulate_debug_inst(run, vcpu); - spin_lock(&vcpu->arch.vcore->lock); } else { kvmppc_core_queue_program(vcpu, SRR1_PROGILL); r = RESUME_GUEST; @@ -1224,12 +1220,8 @@ static int kvmppc_handle_exit_hv(struct kvm_run *run, struct kvm_vcpu *vcpu, case BOOK3S_INTERRUPT_H_FAC_UNAVAIL: r = EMULATE_FAIL; if (((vcpu->arch.hfscr >> 56) == FSCR_MSGP_LG) && - cpu_has_feature(CPU_FTR_ARCH_300)) { - /* Need vcore unlocked to call kvmppc_get_last_inst */ - spin_unlock(&vcpu->arch.vcore->lock); + cpu_has_feature(CPU_FTR_ARCH_300)) r = kvmppc_emulate_doorbell_instr(vcpu); - spin_lock(&vcpu->arch.vcore->lock); - } if (r == EMULATE_FAIL) { kvmppc_core_queue_program(vcpu, SRR1_PROGILL); r = RESUME_GUEST; @@ -2599,6 +2591,14 @@ static void post_guest_process(struct kvmppc_vcore *vc, bool is_master) spin_lock(&vc->lock); now = get_tb(); for_each_runnable_thread(i, vcpu, vc) { + /* + * It's safe to unlock the vcore in the loop here, because + * for_each_runnable_thread() is safe against removal of + * the vcpu, and the vcore state is VCORE_EXITING here, + * so any vcpus becoming runnable will have their arch.trap + * set to zero and can't actually run in the guest. + */ + spin_unlock(&vc->lock); /* cancel pending dec exception if dec is positive */ if (now < vcpu->arch.dec_expires && kvmppc_core_pending_dec(vcpu)) @@ -2614,6 +2614,7 @@ static void post_guest_process(struct kvmppc_vcore *vc, bool is_master) vcpu->arch.ret = ret; vcpu->arch.trap = 0; + spin_lock(&vc->lock); if (is_kvmppc_resume_guest(vcpu->arch.ret)) { if (vcpu->arch.pending_exceptions) kvmppc_core_prepare_to_enter(vcpu); |