Merge branch 'master' of /pub/scm/linux/kernel/git/torvalds/linux-2.6

2 files changed, 473 insertions, 33 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index b2e12893e3f4..c82cf15730a1 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -40,6 +40,7 @@
 #include <linux/kvm_para.h>
 #include <linux/pagemap.h>
 #include <linux/mman.h>
+#include <linux/swap.h>
 
 #include <asm/processor.h>
 #include <asm/io.h>
@@ -59,7 +60,7 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_cache);
 
 static __read_mostly struct preempt_ops kvm_preempt_ops;
 
-static struct dentry *debugfs_dir;
+struct dentry *kvm_debugfs_dir;
 
 static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
                            unsigned long arg);
@@ -119,6 +120,29 @@ void kvm_flush_remote_tlbs(struct kvm *kvm)
         smp_call_function_mask(cpus, ack_flush, NULL, 1);
 }
 
+void kvm_reload_remote_mmus(struct kvm *kvm)
+{
+        int i, cpu;
+        cpumask_t cpus;
+        struct kvm_vcpu *vcpu;
+
+        cpus_clear(cpus);
+        for (i = 0; i < KVM_MAX_VCPUS; ++i) {
+                vcpu = kvm->vcpus[i];
+                if (!vcpu)
+                        continue;
+                if (test_and_set_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests))
+                        continue;
+                cpu = vcpu->cpu;
+                if (cpu != -1 && cpu != raw_smp_processor_id())
+                        cpu_set(cpu, cpus);
+        }
+        if (cpus_empty(cpus))
+                return;
+        smp_call_function_mask(cpus, ack_flush, NULL, 1);
+}
+
+
 int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
 {
         struct page *page;
@@ -170,6 +194,7 @@ static struct kvm *kvm_create_vm(void)
         mutex_init(&kvm->lock);
         kvm_io_bus_init(&kvm->mmio_bus);
         init_rwsem(&kvm->slots_lock);
+        atomic_set(&kvm->users_count, 1);
         spin_lock(&kvm_lock);
         list_add(&kvm->vm_list, &vm_list);
         spin_unlock(&kvm_lock);
@@ -189,9 +214,13 @@ static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
         if (!dont || free->dirty_bitmap != dont->dirty_bitmap)
                 vfree(free->dirty_bitmap);
 
+        if (!dont || free->lpage_info != dont->lpage_info)
+                vfree(free->lpage_info);
+
         free->npages = 0;
         free->dirty_bitmap = NULL;
         free->rmap = NULL;
+        free->lpage_info = NULL;
 }
 
 void kvm_free_physmem(struct kvm *kvm)
@@ -215,11 +244,25 @@ static void kvm_destroy_vm(struct kvm *kvm)
         mmdrop(mm);
 }
 
+void kvm_get_kvm(struct kvm *kvm)
+{
+        atomic_inc(&kvm->users_count);
+}
+EXPORT_SYMBOL_GPL(kvm_get_kvm);
+
+void kvm_put_kvm(struct kvm *kvm)
+{
+        if (atomic_dec_and_test(&kvm->users_count))
+                kvm_destroy_vm(kvm);
+}
+EXPORT_SYMBOL_GPL(kvm_put_kvm);
+
+
 static int kvm_vm_release(struct inode *inode, struct file *filp)
 {
         struct kvm *kvm = filp->private_data;
 
-        kvm_destroy_vm(kvm);
+        kvm_put_kvm(kvm);
         return 0;
 }
 
@@ -301,6 +344,25 @@ int __kvm_set_memory_region(struct kvm *kvm,
                 new.user_alloc = user_alloc;
                 new.userspace_addr = mem->userspace_addr;
         }
+        if (npages && !new.lpage_info) {
+                int largepages = npages / KVM_PAGES_PER_HPAGE;
+                if (npages % KVM_PAGES_PER_HPAGE)
+                        largepages++;
+                if (base_gfn % KVM_PAGES_PER_HPAGE)
+                        largepages++;
+
+                new.lpage_info = vmalloc(largepages * sizeof(*new.lpage_info));
+
+                if (!new.lpage_info)
+                        goto out_free;
+
+                memset(new.lpage_info, 0, largepages * sizeof(*new.lpage_info));
+
+                if (base_gfn % KVM_PAGES_PER_HPAGE)
+                        new.lpage_info[0].write_count = 1;
+                if ((base_gfn+npages) % KVM_PAGES_PER_HPAGE)
+                        new.lpage_info[largepages-1].write_count = 1;
+        }
 
         /* Allocate page dirty bitmap if needed */
         if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) {
@@ -397,6 +459,12 @@ int is_error_page(struct page *page)
 }
 EXPORT_SYMBOL_GPL(is_error_page);
 
+int is_error_pfn(pfn_t pfn)
+{
+        return pfn == bad_pfn;
+}
+EXPORT_SYMBOL_GPL(is_error_pfn);
+
 static inline unsigned long bad_hva(void)
 {
         return PAGE_OFFSET;
@@ -444,7 +512,7 @@ int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
 }
 EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
 
-static unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
+unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
 {
         struct kvm_memory_slot *slot;
 
@@ -458,7 +526,7 @@ static unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
 /*
  * Requires current->mm->mmap_sem to be held
  */
-struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
+pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
 {
         struct page *page[1];
         unsigned long addr;
@@ -469,7 +537,7 @@ struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
         addr = gfn_to_hva(kvm, gfn);
         if (kvm_is_error_hva(addr)) {
                 get_page(bad_page);
-                return bad_page;
+                return page_to_pfn(bad_page);
         }
 
         npages = get_user_pages(current, current->mm, addr, 1, 1, 1, page,
@@ -477,27 +545,71 @@ struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
 
         if (npages != 1) {
                 get_page(bad_page);
-                return bad_page;
+                return page_to_pfn(bad_page);
         }
 
-        return page[0];
+        return page_to_pfn(page[0]);
+}
+
+EXPORT_SYMBOL_GPL(gfn_to_pfn);
+
+struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
+{
+        return pfn_to_page(gfn_to_pfn(kvm, gfn));
 }
 
 EXPORT_SYMBOL_GPL(gfn_to_page);
 
 void kvm_release_page_clean(struct page *page)
 {
-        put_page(page);
+        kvm_release_pfn_clean(page_to_pfn(page));
 }
 EXPORT_SYMBOL_GPL(kvm_release_page_clean);
 
+void kvm_release_pfn_clean(pfn_t pfn)
+{
+        put_page(pfn_to_page(pfn));
+}
+EXPORT_SYMBOL_GPL(kvm_release_pfn_clean);
+
 void kvm_release_page_dirty(struct page *page)
 {
+        kvm_release_pfn_dirty(page_to_pfn(page));
+}
+EXPORT_SYMBOL_GPL(kvm_release_page_dirty);
+
+void kvm_release_pfn_dirty(pfn_t pfn)
+{
+        kvm_set_pfn_dirty(pfn);
+        kvm_release_pfn_clean(pfn);
+}
+EXPORT_SYMBOL_GPL(kvm_release_pfn_dirty);
+
+void kvm_set_page_dirty(struct page *page)
+{
+        kvm_set_pfn_dirty(page_to_pfn(page));
+}
+EXPORT_SYMBOL_GPL(kvm_set_page_dirty);
+
+void kvm_set_pfn_dirty(pfn_t pfn)
+{
+        struct page *page = pfn_to_page(pfn);
         if (!PageReserved(page))
                 SetPageDirty(page);
-        put_page(page);
 }
-EXPORT_SYMBOL_GPL(kvm_release_page_dirty);
+EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty);
+
+void kvm_set_pfn_accessed(pfn_t pfn)
+{
+        mark_page_accessed(pfn_to_page(pfn));
+}
+EXPORT_SYMBOL_GPL(kvm_set_pfn_accessed);
+
+void kvm_get_pfn(pfn_t pfn)
+{
+        get_page(pfn_to_page(pfn));
+}
+EXPORT_SYMBOL_GPL(kvm_get_pfn);
 
 static int next_segment(unsigned long len, int offset)
 {
@@ -554,7 +666,9 @@ int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data,
         addr = gfn_to_hva(kvm, gfn);
         if (kvm_is_error_hva(addr))
                 return -EFAULT;
+        pagefault_disable();
         r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len);
+        pagefault_enable();
         if (r)
                 return -EFAULT;
         return 0;
@@ -651,6 +765,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
          * We will block until either an interrupt or a signal wakes us up
          */
         while (!kvm_cpu_has_interrupt(vcpu)
+               && !kvm_cpu_has_pending_timer(vcpu)
                && !signal_pending(current)
                && !kvm_arch_vcpu_runnable(vcpu)) {
                 set_current_state(TASK_INTERRUPTIBLE);
@@ -678,8 +793,10 @@ static int kvm_vcpu_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 
         if (vmf->pgoff == 0)
                 page = virt_to_page(vcpu->run);
+#ifdef CONFIG_X86
         else if (vmf->pgoff == KVM_PIO_PAGE_OFFSET)
                 page = virt_to_page(vcpu->arch.pio_data);
+#endif
         else
                 return VM_FAULT_SIGBUS;
         get_page(page);
@@ -701,11 +818,11 @@ static int kvm_vcpu_release(struct inode *inode, struct file *filp)
 {
         struct kvm_vcpu *vcpu = filp->private_data;
 
-        fput(vcpu->kvm->filp);
+        kvm_put_kvm(vcpu->kvm);
         return 0;
 }
 
-static struct file_operations kvm_vcpu_fops = {
+static const struct file_operations kvm_vcpu_fops = {
         .release        = kvm_vcpu_release,
         .unlocked_ioctl = kvm_vcpu_ioctl,
         .compat_ioctl   = kvm_vcpu_ioctl,
@@ -723,9 +840,10 @@ static int create_vcpu_fd(struct kvm_vcpu *vcpu)
 
         r = anon_inode_getfd(&fd, &inode, &file,
                              "kvm-vcpu", &kvm_vcpu_fops, vcpu);
-        if (r)
+        if (r) {
+                kvm_put_kvm(vcpu->kvm);
                 return r;
-        atomic_inc(&vcpu->kvm->filp->f_count);
+        }
         return fd;
 }
 
@@ -760,6 +878,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
         mutex_unlock(&kvm->lock);
 
         /* Now it's all set up, let userspace reach it */
+        kvm_get_kvm(kvm);
         r = create_vcpu_fd(vcpu);
         if (r < 0)
                 goto unlink;
@@ -802,28 +921,39 @@ static long kvm_vcpu_ioctl(struct file *filp,
                 r = kvm_arch_vcpu_ioctl_run(vcpu, vcpu->run);
                 break;
         case KVM_GET_REGS: {
-                struct kvm_regs kvm_regs;
+                struct kvm_regs *kvm_regs;
 
-                memset(&kvm_regs, 0, sizeof kvm_regs);
-                r = kvm_arch_vcpu_ioctl_get_regs(vcpu, &kvm_regs);
-                if (r)
+                r = -ENOMEM;
+                kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
+                if (!kvm_regs)
                         goto out;
+                r = kvm_arch_vcpu_ioctl_get_regs(vcpu, kvm_regs);
+                if (r)
+                        goto out_free1;
                 r = -EFAULT;
-                if (copy_to_user(argp, &kvm_regs, sizeof kvm_regs))
-                        goto out;
+                if (copy_to_user(argp, kvm_regs, sizeof(struct kvm_regs)))
+                        goto out_free1;
                 r = 0;
+out_free1:
+                kfree(kvm_regs);
                 break;
         }
         case KVM_SET_REGS: {
-                struct kvm_regs kvm_regs;
+                struct kvm_regs *kvm_regs;
 
-                r = -EFAULT;
-                if (copy_from_user(&kvm_regs, argp, sizeof kvm_regs))
+                r = -ENOMEM;
+                kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
+                if (!kvm_regs)
                         goto out;
-                r = kvm_arch_vcpu_ioctl_set_regs(vcpu, &kvm_regs);
+                r = -EFAULT;
+                if (copy_from_user(kvm_regs, argp, sizeof(struct kvm_regs)))
+                        goto out_free2;
+                r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
                 if (r)
-                        goto out;
+                        goto out_free2;
                 r = 0;
+out_free2:
+                kfree(kvm_regs);
                 break;
         }
         case KVM_GET_SREGS: {
@@ -851,6 +981,30 @@ static long kvm_vcpu_ioctl(struct file *filp,
                 r = 0;
                 break;
         }
+        case KVM_GET_MP_STATE: {
+                struct kvm_mp_state mp_state;
+
+                r = kvm_arch_vcpu_ioctl_get_mpstate(vcpu, &mp_state);
+                if (r)
+                        goto out;
+                r = -EFAULT;
+                if (copy_to_user(argp, &mp_state, sizeof mp_state))
+                        goto out;
+                r = 0;
+                break;
+        }
+        case KVM_SET_MP_STATE: {
+                struct kvm_mp_state mp_state;
+
+                r = -EFAULT;
+                if (copy_from_user(&mp_state, argp, sizeof mp_state))
+                        goto out;
+                r = kvm_arch_vcpu_ioctl_set_mpstate(vcpu, &mp_state);
+                if (r)
+                        goto out;
+                r = 0;
+                break;
+        }
         case KVM_TRANSLATE: {
                 struct kvm_translation tr;
 
@@ -1005,7 +1159,7 @@ static int kvm_vm_mmap(struct file *file, struct vm_area_struct *vma)
         return 0;
 }
 
-static struct file_operations kvm_vm_fops = {
+static const struct file_operations kvm_vm_fops = {
         .release        = kvm_vm_release,
         .unlocked_ioctl = kvm_vm_ioctl,
         .compat_ioctl   = kvm_vm_ioctl,
@@ -1024,12 +1178,10 @@ static int kvm_dev_ioctl_create_vm(void)
                 return PTR_ERR(kvm);
         r = anon_inode_getfd(&fd, &inode, &file, "kvm-vm", &kvm_vm_fops, kvm);
         if (r) {
-                kvm_destroy_vm(kvm);
+                kvm_put_kvm(kvm);
                 return r;
         }
 
-        kvm->filp = file;
-
         return fd;
 }
 
@@ -1059,7 +1211,15 @@ static long kvm_dev_ioctl(struct file *filp,
                 r = -EINVAL;
                 if (arg)
                         goto out;
-                r = 2 * PAGE_SIZE;
+                r = PAGE_SIZE;     /* struct kvm_run */
+#ifdef CONFIG_X86
+                r += PAGE_SIZE;    /* pio data page */
+#endif
+                break;
+        case KVM_TRACE_ENABLE:
+        case KVM_TRACE_PAUSE:
+        case KVM_TRACE_DISABLE:
+                r = kvm_trace_ioctl(ioctl, arg);
                 break;
         default:
                 return kvm_arch_dev_ioctl(filp, ioctl, arg);
@@ -1232,9 +1392,9 @@ static void kvm_init_debug(void)
 {
         struct kvm_stats_debugfs_item *p;
 
-        debugfs_dir = debugfs_create_dir("kvm", NULL);
+        kvm_debugfs_dir = debugfs_create_dir("kvm", NULL);
         for (p = debugfs_entries; p->name; ++p)
-                p->dentry = debugfs_create_file(p->name, 0444, debugfs_dir,
+                p->dentry = debugfs_create_file(p->name, 0444, kvm_debugfs_dir,
                                                 (void *)(long)p->offset,
                                                 stat_fops[p->kind]);
 }
@@ -1245,7 +1405,7 @@ static void kvm_exit_debug(void)
 
         for (p = debugfs_entries; p->name; ++p)
                 debugfs_remove(p->dentry);
-        debugfs_remove(debugfs_dir);
+        debugfs_remove(kvm_debugfs_dir);
 }
 
 static int kvm_suspend(struct sys_device *dev, pm_message_t state)
@@ -1272,6 +1432,7 @@ static struct sys_device kvm_sysdev = {
 };
 
 struct page *bad_page;
+pfn_t bad_pfn;
 
 static inline
 struct kvm_vcpu *preempt_notifier_to_vcpu(struct preempt_notifier *pn)
@@ -1313,6 +1474,8 @@ int kvm_init(void *opaque, unsigned int vcpu_size,
                 goto out;
         }
 
+        bad_pfn = page_to_pfn(bad_page);
+
         r = kvm_arch_hardware_setup();
         if (r < 0)
                 goto out_free_0;
@@ -1386,6 +1549,7 @@ EXPORT_SYMBOL_GPL(kvm_init);
 
 void kvm_exit(void)
 {
+        kvm_trace_cleanup();
         misc_deregister(&kvm_dev);
         kmem_cache_destroy(kvm_vcpu_cache);
         sysdev_unregister(&kvm_sysdev);
diff --git a/virt/kvm/kvm_trace.c b/virt/kvm/kvm_trace.c
new file mode 100644
index 000000000000..0e495470788d
--- /dev/null
+++ b/virt/kvm/kvm_trace.c
@@ -0,0 +1,276 @@
+/*
+ * kvm trace
+ *
+ * It is designed to allow debugging traces of kvm to be generated
+ * on UP / SMP machines.  Each trace entry can be timestamped so that
+ * it's possible to reconstruct a chronological record of trace events.
+ * The implementation refers to blktrace kernel support.
+ *
+ * Copyright (c) 2008 Intel Corporation
+ * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
+ *
+ * Authors: Feng(Eric) Liu, eric.e.liu@intel.com
+ *
+ * Date:    Feb 2008
+ */
+
+#include <linux/module.h>
+#include <linux/relay.h>
+#include <linux/debugfs.h>
+
+#include <linux/kvm_host.h>
+
+#define KVM_TRACE_STATE_RUNNING         (1 << 0)
+#define KVM_TRACE_STATE_PAUSE           (1 << 1)
+#define KVM_TRACE_STATE_CLEARUP         (1 << 2)
+
+struct kvm_trace {
+        int trace_state;
+        struct rchan *rchan;
+        struct dentry *lost_file;
+        atomic_t lost_records;
+};
+static struct kvm_trace *kvm_trace;
+
+struct kvm_trace_probe {
+        const char *name;
+        const char *format;
+        u32 cycle_in;
+        marker_probe_func *probe_func;
+};
+
+static inline int calc_rec_size(int cycle, int extra)
+{
+        int rec_size = KVM_TRC_HEAD_SIZE;
+
+        rec_size += extra;
+        return cycle ? rec_size += KVM_TRC_CYCLE_SIZE : rec_size;
+}
+
+static void kvm_add_trace(void *probe_private, void *call_data,
+                          const char *format, va_list *args)
+{
+        struct kvm_trace_probe *p = probe_private;
+        struct kvm_trace *kt = kvm_trace;
+        struct kvm_trace_rec rec;
+        struct kvm_vcpu *vcpu;
+        int    i, extra, size;
+
+        if (unlikely(kt->trace_state != KVM_TRACE_STATE_RUNNING))
+                return;
+
+        rec.event       = va_arg(*args, u32);
+        vcpu            = va_arg(*args, struct kvm_vcpu *);
+        rec.pid         = current->tgid;
+        rec.vcpu_id     = vcpu->vcpu_id;
+
+        extra           = va_arg(*args, u32);
+        WARN_ON(!(extra <= KVM_TRC_EXTRA_MAX));
+        extra           = min_t(u32, extra, KVM_TRC_EXTRA_MAX);
+        rec.extra_u32   = extra;
+
+        rec.cycle_in    = p->cycle_in;
+
+        if (rec.cycle_in) {
+                u64 cycle = 0;
+
+                cycle = get_cycles();
+                rec.u.cycle.cycle_lo = (u32)cycle;
+                rec.u.cycle.cycle_hi = (u32)(cycle >> 32);
+
+                for (i = 0; i < rec.extra_u32; i++)
+                        rec.u.cycle.extra_u32[i] = va_arg(*args, u32);
+        } else {
+                for (i = 0; i < rec.extra_u32; i++)
+                        rec.u.nocycle.extra_u32[i] = va_arg(*args, u32);
+        }
+
+        size = calc_rec_size(rec.cycle_in, rec.extra_u32 * sizeof(u32));
+        relay_write(kt->rchan, &rec, size);
+}
+
+static struct kvm_trace_probe kvm_trace_probes[] = {
+        { "kvm_trace_entryexit", "%u %p %u %u %u %u %u %u", 1, kvm_add_trace },
+        { "kvm_trace_handler", "%u %p %u %u %u %u %u %u", 0, kvm_add_trace },
+};
+
+static int lost_records_get(void *data, u64 *val)
+{
+        struct kvm_trace *kt = data;
+
+        *val = atomic_read(&kt->lost_records);
+        return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(kvm_trace_lost_ops, lost_records_get, NULL, "%llu\n");
+
+/*
+ *  The relay channel is used in "no-overwrite" mode, it keeps trace of how
+ *  many times we encountered a full subbuffer, to tell user space app the
+ *  lost records there were.
+ */
+static int kvm_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
+                                     void *prev_subbuf, size_t prev_padding)
+{
+        struct kvm_trace *kt;
+
+        if (!relay_buf_full(buf))
+                return 1;
+
+        kt = buf->chan->private_data;
+        atomic_inc(&kt->lost_records);
+
+        return 0;
+}
+
+static struct dentry *kvm_create_buf_file_callack(const char *filename,
+                                                 struct dentry *parent,
+                                                 int mode,
+                                                 struct rchan_buf *buf,
+                                                 int *is_global)
+{
+        return debugfs_create_file(filename, mode, parent, buf,
+                                   &relay_file_operations);
+}
+
+static int kvm_remove_buf_file_callback(struct dentry *dentry)
+{
+        debugfs_remove(dentry);
+        return 0;
+}
+
+static struct rchan_callbacks kvm_relay_callbacks = {
+        .subbuf_start           = kvm_subbuf_start_callback,
+        .create_buf_file        = kvm_create_buf_file_callack,
+        .remove_buf_file        = kvm_remove_buf_file_callback,
+};
+
+static int do_kvm_trace_enable(struct kvm_user_trace_setup *kuts)
+{
+        struct kvm_trace *kt;
+        int i, r = -ENOMEM;
+
+        if (!kuts->buf_size || !kuts->buf_nr)
+                return -EINVAL;
+
+        kt = kzalloc(sizeof(*kt), GFP_KERNEL);
+        if (!kt)
+                goto err;
+
+        r = -EIO;
+        atomic_set(&kt->lost_records, 0);
+        kt->lost_file = debugfs_create_file("lost_records", 0444, kvm_debugfs_dir,
+                                            kt, &kvm_trace_lost_ops);
+        if (!kt->lost_file)
+                goto err;
+
+        kt->rchan = relay_open("trace", kvm_debugfs_dir, kuts->buf_size,
+                                kuts->buf_nr, &kvm_relay_callbacks, kt);
+        if (!kt->rchan)
+                goto err;
+
+        kvm_trace = kt;
+
+        for (i = 0; i < ARRAY_SIZE(kvm_trace_probes); i++) {
+                struct kvm_trace_probe *p = &kvm_trace_probes[i];
+
+                r = marker_probe_register(p->name, p->format, p->probe_func, p);
+                if (r)
+                        printk(KERN_INFO "Unable to register probe %s\n",
+                               p->name);
+        }
+
+        kvm_trace->trace_state = KVM_TRACE_STATE_RUNNING;
+
+        return 0;
+err:
+        if (kt) {
+                if (kt->lost_file)
+                        debugfs_remove(kt->lost_file);
+                if (kt->rchan)
+                        relay_close(kt->rchan);
+                kfree(kt);
+        }
+        return r;
+}
+
+static int kvm_trace_enable(char __user *arg)
+{
+        struct kvm_user_trace_setup kuts;
+        int ret;
+
+        ret = copy_from_user(&kuts, arg, sizeof(kuts));
+        if (ret)
+                return -EFAULT;
+
+        ret = do_kvm_trace_enable(&kuts);
+        if (ret)
+                return ret;
+
+        return 0;
+}
+
+static int kvm_trace_pause(void)
+{
+        struct kvm_trace *kt = kvm_trace;
+        int r = -EINVAL;
+
+        if (kt == NULL)
+                return r;
+
+        if (kt->trace_state == KVM_TRACE_STATE_RUNNING) {
+                kt->trace_state = KVM_TRACE_STATE_PAUSE;
+                relay_flush(kt->rchan);
+                r = 0;
+        }
+
+        return r;
+}
+
+void kvm_trace_cleanup(void)
+{
+        struct kvm_trace *kt = kvm_trace;
+        int i;
+
+        if (kt == NULL)
+                return;
+
+        if (kt->trace_state == KVM_TRACE_STATE_RUNNING ||
+            kt->trace_state == KVM_TRACE_STATE_PAUSE) {
+
+                kt->trace_state = KVM_TRACE_STATE_CLEARUP;
+
+                for (i = 0; i < ARRAY_SIZE(kvm_trace_probes); i++) {
+                        struct kvm_trace_probe *p = &kvm_trace_probes[i];
+                        marker_probe_unregister(p->name, p->probe_func, p);
+                }
+
+                relay_close(kt->rchan);
+                debugfs_remove(kt->lost_file);
+                kfree(kt);
+        }
+}
+
+int kvm_trace_ioctl(unsigned int ioctl, unsigned long arg)
+{
+        void __user *argp = (void __user *)arg;
+        long r = -EINVAL;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        switch (ioctl) {
+        case KVM_TRACE_ENABLE:
+                r = kvm_trace_enable(argp);
+                break;
+        case KVM_TRACE_PAUSE:
+                r = kvm_trace_pause();
+                break;
+        case KVM_TRACE_DISABLE:
+                r = 0;
+                kvm_trace_cleanup();
+                break;
+        }
+
+        return r;
+}