From 898b25b202f3504335ae00055d7a2863bd93f2f8 Mon Sep 17 00:00:00 2001
From: Paul Mackerras <paulus@ozlabs.org>
Date: Thu, 22 Jun 2017 15:08:42 +1000
Subject: [PATCH] KVM: PPC: Book3S HV: Simplify dynamic micro-threading code
References: bsc#1061840
Patch-mainline: v4.13-rc1
Git-commit: 898b25b202f3504335ae00055d7a2863bd93f2f8
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.
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
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 {
--
2.13.6