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KVM: PPC: Book3S HV: Simplify dynamic micro-threading code

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Since commit b009031f74 ("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>
This commit is contained in:
Paul Mackerras
2017-06-22 15:08:42 +10:00
parent 2ed4f9dd19
commit 898b25b202
4 changed files with 39 additions and 54 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
arch/powerpc/include/asm/kvm_book3s.h
View File

@@ -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;

2
arch/powerpc/include/asm/kvm_book3s_asm.h
View File

@@ -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];
};
/*

88
arch/powerpc/kvm/book3s_hv.c
View File

@@ -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)) {

2
arch/powerpc/kvm/book3s_hv_builtin.c
View File

@@ -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 {