1 files changed, 150 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 08f8617f4046..64a02d4c737c 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1423,6 +1423,154 @@ static struct kvmppc_vcore *kvmppc_vcore_create(struct kvm *kvm, int core)
         return vcore;
 }
 
+#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
+static struct debugfs_timings_element {
+        const char *name;
+        size_t offset;
+} timings[] = {
+        {"rm_entry",    offsetof(struct kvm_vcpu, arch.rm_entry)},
+        {"rm_intr",     offsetof(struct kvm_vcpu, arch.rm_intr)},
+        {"rm_exit",     offsetof(struct kvm_vcpu, arch.rm_exit)},
+        {"guest",       offsetof(struct kvm_vcpu, arch.guest_time)},
+        {"cede",        offsetof(struct kvm_vcpu, arch.cede_time)},
+};
+
+#define N_TIMINGS       (sizeof(timings) / sizeof(timings[0]))
+
+struct debugfs_timings_state {
+        struct kvm_vcpu *vcpu;
+        unsigned int    buflen;
+        char            buf[N_TIMINGS * 100];
+};
+
+static int debugfs_timings_open(struct inode *inode, struct file *file)
+{
+        struct kvm_vcpu *vcpu = inode->i_private;
+        struct debugfs_timings_state *p;
+
+        p = kzalloc(sizeof(*p), GFP_KERNEL);
+        if (!p)
+                return -ENOMEM;
+
+        kvm_get_kvm(vcpu->kvm);
+        p->vcpu = vcpu;
+        file->private_data = p;
+
+        return nonseekable_open(inode, file);
+}
+
+static int debugfs_timings_release(struct inode *inode, struct file *file)
+{
+        struct debugfs_timings_state *p = file->private_data;
+
+        kvm_put_kvm(p->vcpu->kvm);
+        kfree(p);
+        return 0;
+}
+
+static ssize_t debugfs_timings_read(struct file *file, char __user *buf,
+                                    size_t len, loff_t *ppos)
+{
+        struct debugfs_timings_state *p = file->private_data;
+        struct kvm_vcpu *vcpu = p->vcpu;
+        char *s, *buf_end;
+        struct kvmhv_tb_accumulator tb;
+        u64 count;
+        loff_t pos;
+        ssize_t n;
+        int i, loops;
+        bool ok;
+
+        if (!p->buflen) {
+                s = p->buf;
+                buf_end = s + sizeof(p->buf);
+                for (i = 0; i < N_TIMINGS; ++i) {
+                        struct kvmhv_tb_accumulator *acc;
+
+                        acc = (struct kvmhv_tb_accumulator *)
+                                ((unsigned long)vcpu + timings[i].offset);
+                        ok = false;
+                        for (loops = 0; loops < 1000; ++loops) {
+                                count = acc->seqcount;
+                                if (!(count & 1)) {
+                                        smp_rmb();
+                                        tb = *acc;
+                                        smp_rmb();
+                                        if (count == acc->seqcount) {
+                                                ok = true;
+                                                break;
+                                        }
+                                }
+                                udelay(1);
+                        }
+                        if (!ok)
+                                snprintf(s, buf_end - s, "%s: stuck\n",
+                                        timings[i].name);
+                        else
+                                snprintf(s, buf_end - s,
+                                        "%s: %llu %llu %llu %llu\n",
+                                        timings[i].name, count / 2,
+                                        tb_to_ns(tb.tb_total),
+                                        tb_to_ns(tb.tb_min),
+                                        tb_to_ns(tb.tb_max));
+                        s += strlen(s);
+                }
+                p->buflen = s - p->buf;
+        }
+
+        pos = *ppos;
+        if (pos >= p->buflen)
+                return 0;
+        if (len > p->buflen - pos)
+                len = p->buflen - pos;
+        n = copy_to_user(buf, p->buf + pos, len);
+        if (n) {
+                if (n == len)
+                        return -EFAULT;
+                len -= n;
+        }
+        *ppos = pos + len;
+        return len;
+}
+
+static ssize_t debugfs_timings_write(struct file *file, const char __user *buf,
+                                     size_t len, loff_t *ppos)
+{
+        return -EACCES;
+}
+
+static const struct file_operations debugfs_timings_ops = {
+        .owner   = THIS_MODULE,
+        .open    = debugfs_timings_open,
+        .release = debugfs_timings_release,
+        .read    = debugfs_timings_read,
+        .write   = debugfs_timings_write,
+        .llseek  = generic_file_llseek,
+};
+
+/* Create a debugfs directory for the vcpu */
+static void debugfs_vcpu_init(struct kvm_vcpu *vcpu, unsigned int id)
+{
+        char buf[16];
+        struct kvm *kvm = vcpu->kvm;
+
+        snprintf(buf, sizeof(buf), "vcpu%u", id);
+        if (IS_ERR_OR_NULL(kvm->arch.debugfs_dir))
+                return;
+        vcpu->arch.debugfs_dir = debugfs_create_dir(buf, kvm->arch.debugfs_dir);
+        if (IS_ERR_OR_NULL(vcpu->arch.debugfs_dir))
+                return;
+        vcpu->arch.debugfs_timings =
+                debugfs_create_file("timings", 0444, vcpu->arch.debugfs_dir,
+                                    vcpu, &debugfs_timings_ops);
+}
+
+#else /* CONFIG_KVM_BOOK3S_HV_EXIT_TIMING */
+static void debugfs_vcpu_init(struct kvm_vcpu *vcpu, unsigned int id)
+{
+}
+#endif /* CONFIG_KVM_BOOK3S_HV_EXIT_TIMING */
+
 static struct kvm_vcpu *kvmppc_core_vcpu_create_hv(struct kvm *kvm,
                                                    unsigned int id)
 {
@@ -1492,6 +1640,8 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_hv(struct kvm *kvm,
         vcpu->arch.cpu_type = KVM_CPU_3S_64;
         kvmppc_sanity_check(vcpu);
 
+        debugfs_vcpu_init(vcpu, id);
+
         return vcpu;
 
 free_vcpu: