On Tue, Jun 27, 2017 at 04:07:56PM +1000, Paul Mackerras wrote:
> Since commit b009031f74da ("KVM: PPC: Book3S HV: Take out virtual
> core piggybacking code", 2016-09-15), we only have at most one
> vcore per subcore. Previously, the fact that there might be more
> than one vcore per subcore meant that we had the notion of a
> "master vcore", which was the vcore that controlled thread 0 of
> the subcore. We also needed a list per subcore in the core_info
> struct to record which vcores belonged to each subcore. Now that
> there can only be one vcore in the subcore, we can replace the
> list with a simple pointer and get rid of the notion of the
> master vcore (and in fact treat every vcore as a master vcore).
>
> We can also get rid of the subcore_vm[] field in the core_info
> struct since it is never read.
>
> Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx>
Reviewed-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> ---
> arch/powerpc/include/asm/kvm_book3s.h | 1 -
> arch/powerpc/include/asm/kvm_book3s_asm.h | 2 +-
> arch/powerpc/kvm/book3s_hv.c | 88 +++++++++++++------------------
> arch/powerpc/kvm/book3s_hv_builtin.c | 2 +-
> 4 files changed, 39 insertions(+), 54 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
> index 2bf35017ffc0..b8d5b8e35244 100644
> --- a/arch/powerpc/include/asm/kvm_book3s.h
> +++ b/arch/powerpc/include/asm/kvm_book3s.h
> @@ -86,7 +86,6 @@ struct kvmppc_vcore {
> u16 last_cpu;
> u8 vcore_state;
> u8 in_guest;
> - struct kvmppc_vcore *master_vcore;
> struct kvm_vcpu *runnable_threads[MAX_SMT_THREADS];
> struct list_head preempt_list;
> spinlock_t lock;
> diff --git a/arch/powerpc/include/asm/kvm_book3s_asm.h b/arch/powerpc/include/asm/kvm_book3s_asm.h
> index b148496ffe36..7cea76f11c26 100644
> --- a/arch/powerpc/include/asm/kvm_book3s_asm.h
> +++ b/arch/powerpc/include/asm/kvm_book3s_asm.h
> @@ -81,7 +81,7 @@ struct kvm_split_mode {
> u8 subcore_size;
> u8 do_nap;
> u8 napped[MAX_SMT_THREADS];
> - struct kvmppc_vcore *master_vcs[MAX_SUBCORES];
> + struct kvmppc_vcore *vc[MAX_SUBCORES];
> };
>
> /*
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index c4ada89be658..03d6c7f9b547 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -2171,7 +2171,6 @@ static void kvmppc_start_thread(struct kvm_vcpu *vcpu, struct kvmppc_vcore *vc)
> {
> int cpu;
> struct paca_struct *tpaca;
> - struct kvmppc_vcore *mvc = vc->master_vcore;
> struct kvm *kvm = vc->kvm;
>
> cpu = vc->pcpu;
> @@ -2181,7 +2180,7 @@ static void kvmppc_start_thread(struct kvm_vcpu *vcpu, struct kvmppc_vcore *vc)
> vcpu->arch.timer_running = 0;
> }
> cpu += vcpu->arch.ptid;
> - vcpu->cpu = mvc->pcpu;
> + vcpu->cpu = vc->pcpu;
> vcpu->arch.thread_cpu = cpu;
>
> /*
> @@ -2207,10 +2206,10 @@ static void kvmppc_start_thread(struct kvm_vcpu *vcpu, struct kvmppc_vcore *vc)
> }
> tpaca = &paca[cpu];
> tpaca->kvm_hstate.kvm_vcpu = vcpu;
> - tpaca->kvm_hstate.ptid = cpu - mvc->pcpu;
> + tpaca->kvm_hstate.ptid = cpu - vc->pcpu;
> /* Order stores to hstate.kvm_vcpu etc. before store to kvm_vcore */
> smp_wmb();
> - tpaca->kvm_hstate.kvm_vcore = mvc;
> + tpaca->kvm_hstate.kvm_vcore = vc;
> if (cpu != smp_processor_id())
> kvmppc_ipi_thread(cpu);
> }
> @@ -2339,8 +2338,7 @@ struct core_info {
> int max_subcore_threads;
> int total_threads;
> int subcore_threads[MAX_SUBCORES];
> - struct kvm *subcore_vm[MAX_SUBCORES];
> - struct list_head vcs[MAX_SUBCORES];
> + struct kvmppc_vcore *vc[MAX_SUBCORES];
> };
>
> /*
> @@ -2351,17 +2349,12 @@ static int subcore_thread_map[MAX_SUBCORES] = { 0, 4, 2, 6 };
>
> static void init_core_info(struct core_info *cip, struct kvmppc_vcore *vc)
> {
> - int sub;
> -
> memset(cip, 0, sizeof(*cip));
> cip->n_subcores = 1;
> cip->max_subcore_threads = vc->num_threads;
> cip->total_threads = vc->num_threads;
> cip->subcore_threads[0] = vc->num_threads;
> - cip->subcore_vm[0] = vc->kvm;
> - for (sub = 0; sub < MAX_SUBCORES; ++sub)
> - INIT_LIST_HEAD(&cip->vcs[sub]);
> - list_add_tail(&vc->preempt_list, &cip->vcs[0]);
> + cip->vc[0] = vc;
> }
>
> static bool subcore_config_ok(int n_subcores, int n_threads)
> @@ -2381,9 +2374,8 @@ static bool subcore_config_ok(int n_subcores, int n_threads)
> return n_subcores * roundup_pow_of_two(n_threads) <= MAX_SMT_THREADS;
> }
>
> -static void init_master_vcore(struct kvmppc_vcore *vc)
> +static void init_vcore_to_run(struct kvmppc_vcore *vc)
> {
> - vc->master_vcore = vc;
> vc->entry_exit_map = 0;
> vc->in_guest = 0;
> vc->napping_threads = 0;
> @@ -2408,9 +2400,9 @@ static bool can_dynamic_split(struct kvmppc_vcore *vc, struct core_info *cip)
> ++cip->n_subcores;
> cip->total_threads += vc->num_threads;
> cip->subcore_threads[sub] = vc->num_threads;
> - cip->subcore_vm[sub] = vc->kvm;
> - init_master_vcore(vc);
> - list_move_tail(&vc->preempt_list, &cip->vcs[sub]);
> + cip->vc[sub] = vc;
> + init_vcore_to_run(vc);
> + list_del_init(&vc->preempt_list);
>
> return true;
> }
> @@ -2515,7 +2507,6 @@ static void post_guest_process(struct kvmppc_vcore *vc, bool is_master)
> wake_up(&vcpu->arch.cpu_run);
> }
> }
> - list_del_init(&vc->preempt_list);
> if (!is_master) {
> if (still_running > 0) {
> kvmppc_vcore_preempt(vc);
> @@ -2587,7 +2578,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
> int i;
> int srcu_idx;
> struct core_info core_info;
> - struct kvmppc_vcore *pvc, *vcnext;
> + struct kvmppc_vcore *pvc;
> struct kvm_split_mode split_info, *sip;
> int split, subcore_size, active;
> int sub;
> @@ -2610,7 +2601,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
> /*
> * Initialize *vc.
> */
> - init_master_vcore(vc);
> + init_vcore_to_run(vc);
> vc->preempt_tb = TB_NIL;
>
> /*
> @@ -2670,9 +2661,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
> split_info.ldbar = mfspr(SPRN_LDBAR);
> split_info.subcore_size = subcore_size;
> for (sub = 0; sub < core_info.n_subcores; ++sub)
> - split_info.master_vcs[sub] =
> - list_first_entry(&core_info.vcs[sub],
> - struct kvmppc_vcore, preempt_list);
> + split_info.vc[sub] = core_info.vc[sub];
> /* order writes to split_info before kvm_split_mode pointer */
> smp_wmb();
> }
> @@ -2704,24 +2693,23 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
> thr = subcore_thread_map[sub];
> thr0_done = false;
> active |= 1 << thr;
> - list_for_each_entry(pvc, &core_info.vcs[sub], preempt_list) {
> - pvc->pcpu = pcpu + thr;
> - for_each_runnable_thread(i, vcpu, pvc) {
> - kvmppc_start_thread(vcpu, pvc);
> - kvmppc_create_dtl_entry(vcpu, pvc);
> - trace_kvm_guest_enter(vcpu);
> - if (!vcpu->arch.ptid)
> - thr0_done = true;
> - active |= 1 << (thr + vcpu->arch.ptid);
> - }
> - /*
> - * We need to start the first thread of each subcore
> - * even if it doesn't have a vcpu.
> - */
> - if (pvc->master_vcore == pvc && !thr0_done)
> - kvmppc_start_thread(NULL, pvc);
> - thr += pvc->num_threads;
> + pvc = core_info.vc[sub];
> + pvc->pcpu = pcpu + thr;
> + for_each_runnable_thread(i, vcpu, pvc) {
> + kvmppc_start_thread(vcpu, pvc);
> + kvmppc_create_dtl_entry(vcpu, pvc);
> + trace_kvm_guest_enter(vcpu);
> + if (!vcpu->arch.ptid)
> + thr0_done = true;
> + active |= 1 << (thr + vcpu->arch.ptid);
> }
> + /*
> + * We need to start the first thread of each subcore
> + * even if it doesn't have a vcpu.
> + */
> + if (!thr0_done)
> + kvmppc_start_thread(NULL, pvc);
> + thr += pvc->num_threads;
> }
>
> /*
> @@ -2748,8 +2736,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
> trace_kvmppc_run_core(vc, 0);
>
> for (sub = 0; sub < core_info.n_subcores; ++sub)
> - list_for_each_entry(pvc, &core_info.vcs[sub], preempt_list)
> - spin_unlock(&pvc->lock);
> + spin_unlock(&core_info.vc[sub]->lock);
>
> guest_enter();
>
> @@ -2802,10 +2789,10 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
> smp_mb();
> guest_exit();
>
> - for (sub = 0; sub < core_info.n_subcores; ++sub)
> - list_for_each_entry_safe(pvc, vcnext, &core_info.vcs[sub],
> - preempt_list)
> - post_guest_process(pvc, pvc == vc);
> + for (sub = 0; sub < core_info.n_subcores; ++sub) {
> + pvc = core_info.vc[sub];
> + post_guest_process(pvc, pvc == vc);
> + }
>
> spin_lock(&vc->lock);
> preempt_enable();
> @@ -3026,15 +3013,14 @@ static int kvmppc_run_vcpu(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
> */
> if (!signal_pending(current)) {
> if (vc->vcore_state == VCORE_PIGGYBACK) {
> - struct kvmppc_vcore *mvc = vc->master_vcore;
> - if (spin_trylock(&mvc->lock)) {
> - if (mvc->vcore_state == VCORE_RUNNING &&
> - !VCORE_IS_EXITING(mvc)) {
> + if (spin_trylock(&vc->lock)) {
> + if (vc->vcore_state == VCORE_RUNNING &&
> + !VCORE_IS_EXITING(vc)) {
> kvmppc_create_dtl_entry(vcpu, vc);
> kvmppc_start_thread(vcpu, vc);
> trace_kvm_guest_enter(vcpu);
> }
> - spin_unlock(&mvc->lock);
> + spin_unlock(&vc->lock);
> }
> } else if (vc->vcore_state == VCORE_RUNNING &&
> !VCORE_IS_EXITING(vc)) {
> diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
> index ee4c2558c305..90644db9d38e 100644
> --- a/arch/powerpc/kvm/book3s_hv_builtin.c
> +++ b/arch/powerpc/kvm/book3s_hv_builtin.c
> @@ -307,7 +307,7 @@ void kvmhv_commence_exit(int trap)
> return;
>
> for (i = 0; i < MAX_SUBCORES; ++i) {
> - vc = sip->master_vcs[i];
> + vc = sip->vc[i];
> if (!vc)
> break;
> do {
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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