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-rw-r--r--arch/powerpc/include/asm/kvm_host.h1
-rw-r--r--arch/powerpc/kvm/book3s_hv.c87
-rw-r--r--arch/powerpc/kvm/book3s_hv_rmhandlers.S2
3 files changed, 57 insertions, 33 deletions
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index d831a3883175..3aa5b577cd60 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -281,6 +281,7 @@ struct kvm_arch {
cpumask_t cpu_in_guest;
u8 radix;
u8 fwnmi_enabled;
+ bool threads_indep;
pgd_t *pgtable;
u64 process_table;
struct dentry *debugfs_dir;
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 040e102de4ef..b5fbf7617952 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -98,6 +98,10 @@ static int target_smt_mode;
module_param(target_smt_mode, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(target_smt_mode, "Target threads per core (0 = max)");
+static bool indep_threads_mode = true;
+module_param(indep_threads_mode, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(indep_threads_mode, "Independent-threads mode (only on POWER9)");
+
#ifdef CONFIG_KVM_XICS
static struct kernel_param_ops module_param_ops = {
.set = param_set_int,
@@ -1734,9 +1738,9 @@ static int kvmppc_set_one_reg_hv(struct kvm_vcpu *vcpu, u64 id,
* MMU mode (radix or HPT), unfortunately, but since we only support
* HPT guests on a HPT host so far, that isn't an impediment yet.
*/
-static int threads_per_vcore(void)
+static int threads_per_vcore(struct kvm *kvm)
{
- if (cpu_has_feature(CPU_FTR_ARCH_300))
+ if (kvm->arch.threads_indep)
return 1;
return threads_per_subcore;
}
@@ -2228,11 +2232,10 @@ static void kvmppc_start_thread(struct kvm_vcpu *vcpu, struct kvmppc_vcore *vc)
kvmppc_ipi_thread(cpu);
}
-static void kvmppc_wait_for_nap(void)
+static void kvmppc_wait_for_nap(int n_threads)
{
int cpu = smp_processor_id();
int i, loops;
- int n_threads = threads_per_vcore();
if (n_threads <= 1)
return;
@@ -2319,7 +2322,7 @@ static void kvmppc_vcore_preempt(struct kvmppc_vcore *vc)
vc->vcore_state = VCORE_PREEMPT;
vc->pcpu = smp_processor_id();
- if (vc->num_threads < threads_per_vcore()) {
+ if (vc->num_threads < threads_per_vcore(vc->kvm)) {
spin_lock(&lp->lock);
list_add_tail(&vc->preempt_list, &lp->list);
spin_unlock(&lp->lock);
@@ -2357,7 +2360,7 @@ struct core_info {
/*
* This mapping means subcores 0 and 1 can use threads 0-3 and 4-7
- * respectively in 2-way micro-threading (split-core) mode.
+ * respectively in 2-way micro-threading (split-core) mode on POWER8.
*/
static int subcore_thread_map[MAX_SUBCORES] = { 0, 4, 2, 6 };
@@ -2373,7 +2376,14 @@ static void init_core_info(struct core_info *cip, struct kvmppc_vcore *vc)
static bool subcore_config_ok(int n_subcores, int n_threads)
{
- /* Can only dynamically split if unsplit to begin with */
+ /*
+ * POWER9 "SMT4" cores are permanently in what is effectively a 4-way split-core
+ * mode, with one thread per subcore.
+ */
+ if (cpu_has_feature(CPU_FTR_ARCH_300))
+ return n_subcores <= 4 && n_threads == 1;
+
+ /* On POWER8, can only dynamically split if unsplit to begin with */
if (n_subcores > 1 && threads_per_subcore < MAX_SMT_THREADS)
return false;
if (n_subcores > MAX_SUBCORES)
@@ -2632,6 +2642,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
int target_threads;
int controlled_threads;
int trap;
+ bool is_power8;
/*
* Remove from the list any threads that have a signal pending
@@ -2654,7 +2665,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
* the number of threads per subcore, except on POWER9,
* where it's 1 because the threads are (mostly) independent.
*/
- controlled_threads = threads_per_vcore();
+ controlled_threads = threads_per_vcore(vc->kvm);
/*
* Make sure we are running on primary threads, and that secondary
@@ -2725,32 +2736,40 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
cmd_bit = stat_bit = 0;
split = core_info.n_subcores;
sip = NULL;
+ is_power8 = cpu_has_feature(CPU_FTR_ARCH_207S)
+ && !cpu_has_feature(CPU_FTR_ARCH_300);
+
if (split > 1) {
- /* threads_per_subcore must be MAX_SMT_THREADS (8) here */
- if (split == 2 && (dynamic_mt_modes & 2)) {
- cmd_bit = HID0_POWER8_1TO2LPAR;
- stat_bit = HID0_POWER8_2LPARMODE;
- } else {
- split = 4;
- cmd_bit = HID0_POWER8_1TO4LPAR;
- stat_bit = HID0_POWER8_4LPARMODE;
- }
- subcore_size = MAX_SMT_THREADS / split;
sip = &split_info;
memset(&split_info, 0, sizeof(split_info));
- split_info.rpr = mfspr(SPRN_RPR);
- split_info.pmmar = mfspr(SPRN_PMMAR);
- split_info.ldbar = mfspr(SPRN_LDBAR);
- split_info.subcore_size = subcore_size;
for (sub = 0; sub < core_info.n_subcores; ++sub)
split_info.vc[sub] = core_info.vc[sub];
+
+ if (is_power8) {
+ if (split == 2 && (dynamic_mt_modes & 2)) {
+ cmd_bit = HID0_POWER8_1TO2LPAR;
+ stat_bit = HID0_POWER8_2LPARMODE;
+ } else {
+ split = 4;
+ cmd_bit = HID0_POWER8_1TO4LPAR;
+ stat_bit = HID0_POWER8_4LPARMODE;
+ }
+ subcore_size = MAX_SMT_THREADS / split;
+ split_info.rpr = mfspr(SPRN_RPR);
+ split_info.pmmar = mfspr(SPRN_PMMAR);
+ split_info.ldbar = mfspr(SPRN_LDBAR);
+ split_info.subcore_size = subcore_size;
+ } else {
+ split_info.subcore_size = 1;
+ }
+
/* order writes to split_info before kvm_split_mode pointer */
smp_wmb();
}
for (thr = 0; thr < controlled_threads; ++thr)
paca[pcpu + thr].kvm_hstate.kvm_split_mode = sip;
- /* Initiate micro-threading (split-core) if required */
+ /* Initiate micro-threading (split-core) on POWER8 if required */
if (cmd_bit) {
unsigned long hid0 = mfspr(SPRN_HID0);
@@ -2769,7 +2788,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
/* Start all the threads */
active = 0;
for (sub = 0; sub < core_info.n_subcores; ++sub) {
- thr = subcore_thread_map[sub];
+ thr = is_power8 ? subcore_thread_map[sub] : sub;
thr0_done = false;
active |= 1 << thr;
pvc = core_info.vc[sub];
@@ -2796,18 +2815,18 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
* the vcore pointer in the PACA of the secondaries.
*/
smp_mb();
- if (cmd_bit)
- split_info.do_nap = 1; /* ask secondaries to nap when done */
/*
* When doing micro-threading, poke the inactive threads as well.
* This gets them to the nap instruction after kvm_do_nap,
* which reduces the time taken to unsplit later.
*/
- if (split > 1)
+ if (cmd_bit) {
+ split_info.do_nap = 1; /* ask secondaries to nap when done */
for (thr = 1; thr < threads_per_subcore; ++thr)
if (!(active & (1 << thr)))
kvmppc_ipi_thread(pcpu + thr);
+ }
vc->vcore_state = VCORE_RUNNING;
preempt_disable();
@@ -2841,10 +2860,10 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
vc->vcore_state = VCORE_EXITING;
/* wait for secondary threads to finish writing their state to memory */
- kvmppc_wait_for_nap();
+ kvmppc_wait_for_nap(controlled_threads);
/* Return to whole-core mode if we split the core earlier */
- if (split > 1) {
+ if (cmd_bit) {
unsigned long hid0 = mfspr(SPRN_HID0);
unsigned long loops = 0;
@@ -3822,10 +3841,12 @@ static int kvmppc_core_init_vm_hv(struct kvm *kvm)
/*
* Track that we now have a HV mode VM active. This blocks secondary
* CPU threads from coming online.
- * On POWER9, we only need to do this for HPT guests on a radix
- * host, which is not yet supported.
+ * On POWER9, we only need to do this if the "indep_threads_mode"
+ * module parameter has been set to N.
*/
- if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ if (cpu_has_feature(CPU_FTR_ARCH_300))
+ kvm->arch.threads_indep = indep_threads_mode;
+ if (!kvm->arch.threads_indep)
kvm_hv_vm_activated();
/*
@@ -3865,7 +3886,7 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm)
{
debugfs_remove_recursive(kvm->arch.debugfs_dir);
- if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ if (!kvm->arch.threads_indep)
kvm_hv_vm_deactivated();
kvmppc_free_vcores(kvm);
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index fd2583ddc9a9..ae6c61641ade 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -385,6 +385,7 @@ kvm_secondary_got_guest:
ld r6, 0(r6)
mtspr SPRN_HDEC, r6
/* and set per-LPAR registers, if doing dynamic micro-threading */
+BEGIN_FTR_SECTION
ld r6, HSTATE_SPLIT_MODE(r13)
cmpdi r6, 0
beq 63f
@@ -395,6 +396,7 @@ kvm_secondary_got_guest:
ld r0, KVM_SPLIT_LDBAR(r6)
mtspr SPRN_LDBAR, r0
isync
+END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
63:
/* Order load of vcpu after load of vcore */
lwsync
generated by cgit (git 2.34.1) at 2024-05-25 22:56:46 +0000