KVM: use __copy_to_user/__clear_user to write guest page
[linux-2.6.git] / virt / kvm / kvm_main.c
index a3a8f5f..087b3f8 100644 (file)
@@ -30,7 +30,7 @@
 #include <linux/debugfs.h>
 #include <linux/highmem.h>
 #include <linux/file.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/cpu.h>
 #include <linux/sched.h>
 #include <linux/cpumask.h>
@@ -52,7 +52,6 @@
 #include <asm/io.h>
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
-#include <asm-generic/bitops/le.h>
 
 #include "coalesced_mmio.h"
 #include "async_pf.h"
@@ -69,7 +68,7 @@ MODULE_LICENSE("GPL");
  *             kvm->lock --> kvm->slots_lock --> kvm->irq_lock
  */
 
-DEFINE_SPINLOCK(kvm_lock);
+DEFINE_RAW_SPINLOCK(kvm_lock);
 LIST_HEAD(vm_list);
 
 static cpumask_var_t cpus_hardware_enabled;
@@ -137,6 +136,14 @@ void vcpu_load(struct kvm_vcpu *vcpu)
        int cpu;
 
        mutex_lock(&vcpu->mutex);
+       if (unlikely(vcpu->pid != current->pids[PIDTYPE_PID].pid)) {
+               /* The thread running this VCPU changed. */
+               struct pid *oldpid = vcpu->pid;
+               struct pid *newpid = get_task_pid(current, PIDTYPE_PID);
+               rcu_assign_pointer(vcpu->pid, newpid);
+               synchronize_rcu();
+               put_pid(oldpid);
+       }
        cpu = get_cpu();
        preempt_notifier_register(&vcpu->preempt_notifier);
        kvm_arch_vcpu_load(vcpu, cpu);
@@ -165,13 +172,16 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
 
        zalloc_cpumask_var(&cpus, GFP_ATOMIC);
 
-       raw_spin_lock(&kvm->requests_lock);
-       me = smp_processor_id();
+       me = get_cpu();
        kvm_for_each_vcpu(i, vcpu, kvm) {
-               if (kvm_make_check_request(req, vcpu))
-                       continue;
+               kvm_make_request(req, vcpu);
                cpu = vcpu->cpu;
-               if (cpus != NULL && cpu != -1 && cpu != me)
+
+               /* Set ->requests bit before we read ->mode */
+               smp_mb();
+
+               if (cpus != NULL && cpu != -1 && cpu != me &&
+                     kvm_vcpu_exiting_guest_mode(vcpu) != OUTSIDE_GUEST_MODE)
                        cpumask_set_cpu(cpu, cpus);
        }
        if (unlikely(cpus == NULL))
@@ -180,7 +190,7 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
                smp_call_function_many(cpus, ack_flush, NULL, 1);
        else
                called = false;
-       raw_spin_unlock(&kvm->requests_lock);
+       put_cpu();
        free_cpumask_var(cpus);
        return called;
 }
@@ -209,6 +219,7 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
        vcpu->cpu = -1;
        vcpu->kvm = kvm;
        vcpu->vcpu_id = id;
+       vcpu->pid = NULL;
        init_waitqueue_head(&vcpu->wq);
        kvm_async_pf_vcpu_init(vcpu);
 
@@ -233,6 +244,7 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_init);
 
 void kvm_vcpu_uninit(struct kvm_vcpu *vcpu)
 {
+       put_pid(vcpu->pid);
        kvm_arch_vcpu_uninit(vcpu);
        free_page((unsigned long)vcpu->run);
 }
@@ -456,22 +468,22 @@ static struct kvm *kvm_create_vm(void)
                        goto out_err;
        }
 
-       r = kvm_init_mmu_notifier(kvm);
-       if (r)
-               goto out_err;
-
+       spin_lock_init(&kvm->mmu_lock);
        kvm->mm = current->mm;
        atomic_inc(&kvm->mm->mm_count);
-       spin_lock_init(&kvm->mmu_lock);
-       raw_spin_lock_init(&kvm->requests_lock);
        kvm_eventfd_init(kvm);
        mutex_init(&kvm->lock);
        mutex_init(&kvm->irq_lock);
        mutex_init(&kvm->slots_lock);
        atomic_set(&kvm->users_count, 1);
-       spin_lock(&kvm_lock);
+
+       r = kvm_init_mmu_notifier(kvm);
+       if (r)
+               goto out_err;
+
+       raw_spin_lock(&kvm_lock);
        list_add(&kvm->vm_list, &vm_list);
-       spin_unlock(&kvm_lock);
+       raw_spin_unlock(&kvm_lock);
 
        return kvm;
 
@@ -544,9 +556,9 @@ static void kvm_destroy_vm(struct kvm *kvm)
        struct mm_struct *mm = kvm->mm;
 
        kvm_arch_sync_events(kvm);
-       spin_lock(&kvm_lock);
+       raw_spin_lock(&kvm_lock);
        list_del(&kvm->vm_list);
-       spin_unlock(&kvm_lock);
+       raw_spin_unlock(&kvm_lock);
        kvm_free_irq_routing(kvm);
        for (i = 0; i < KVM_NR_BUSES; i++)
                kvm_io_bus_destroy(kvm->buses[i]);
@@ -588,6 +600,7 @@ static int kvm_vm_release(struct inode *inode, struct file *filp)
        return 0;
 }
 
+#ifndef CONFIG_S390
 /*
  * Allocation size is twice as large as the actual dirty bitmap size.
  * This makes it possible to do double buffering: see x86's
@@ -608,6 +621,7 @@ static int kvm_create_dirty_bitmap(struct kvm_memory_slot *memslot)
        memslot->dirty_bitmap_head = memslot->dirty_bitmap;
        return 0;
 }
+#endif /* !CONFIG_S390 */
 
 /*
  * Allocate some memory and give it an address in the guest physical address
@@ -635,7 +649,12 @@ int __kvm_set_memory_region(struct kvm *kvm,
                goto out;
        if (mem->guest_phys_addr & (PAGE_SIZE - 1))
                goto out;
-       if (user_alloc && (mem->userspace_addr & (PAGE_SIZE - 1)))
+       /* We can read the guest memory with __xxx_user() later on. */
+       if (user_alloc &&
+           ((mem->userspace_addr & (PAGE_SIZE - 1)) ||
+            !access_ok(VERIFY_WRITE,
+                       (void __user *)(unsigned long)mem->userspace_addr,
+                       mem->memory_size)))
                goto out;
        if (mem->slot >= KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS)
                goto out;
@@ -983,23 +1002,6 @@ out:
        return size;
 }
 
-int memslot_id(struct kvm *kvm, gfn_t gfn)
-{
-       int i;
-       struct kvm_memslots *slots = kvm_memslots(kvm);
-       struct kvm_memory_slot *memslot = NULL;
-
-       for (i = 0; i < slots->nmemslots; ++i) {
-               memslot = &slots->memslots[i];
-
-               if (gfn >= memslot->base_gfn
-                   && gfn < memslot->base_gfn + memslot->npages)
-                       break;
-       }
-
-       return memslot - slots->memslots;
-}
-
 static unsigned long gfn_to_hva_many(struct kvm_memory_slot *slot, gfn_t gfn,
                                     gfn_t *nr_pages)
 {
@@ -1024,6 +1026,26 @@ static pfn_t get_fault_pfn(void)
        return fault_pfn;
 }
 
+int get_user_page_nowait(struct task_struct *tsk, struct mm_struct *mm,
+       unsigned long start, int write, struct page **page)
+{
+       int flags = FOLL_TOUCH | FOLL_NOWAIT | FOLL_HWPOISON | FOLL_GET;
+
+       if (write)
+               flags |= FOLL_WRITE;
+
+       return __get_user_pages(tsk, mm, start, 1, flags, page, NULL, NULL);
+}
+
+static inline int check_user_page_hwpoison(unsigned long addr)
+{
+       int rc, flags = FOLL_TOUCH | FOLL_HWPOISON | FOLL_WRITE;
+
+       rc = __get_user_pages(current, current->mm, addr, 1,
+                             flags, NULL, NULL, NULL);
+       return rc == -EHWPOISON;
+}
+
 static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic,
                        bool *async, bool write_fault, bool *writable)
 {
@@ -1048,7 +1070,14 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic,
                if (writable)
                        *writable = write_fault;
 
-               npages = get_user_pages_fast(addr, 1, write_fault, page);
+               if (async) {
+                       down_read(&current->mm->mmap_sem);
+                       npages = get_user_page_nowait(current, current->mm,
+                                                    addr, write_fault, page);
+                       up_read(&current->mm->mmap_sem);
+               } else
+                       npages = get_user_pages_fast(addr, 1, write_fault,
+                                                    page);
 
                /* map read fault as writable if possible */
                if (unlikely(!write_fault) && npages == 1) {
@@ -1071,7 +1100,8 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic,
                        return get_fault_pfn();
 
                down_read(&current->mm->mmap_sem);
-               if (is_hwpoison_address(addr)) {
+               if (npages == -EHWPOISON ||
+                       (!async && check_user_page_hwpoison(addr))) {
                        up_read(&current->mm->mmap_sem);
                        get_page(hwpoison_page);
                        return page_to_pfn(hwpoison_page);
@@ -1259,7 +1289,7 @@ int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
        addr = gfn_to_hva(kvm, gfn);
        if (kvm_is_error_hva(addr))
                return -EFAULT;
-       r = copy_from_user(data, (void __user *)addr + offset, len);
+       r = __copy_from_user(data, (void __user *)addr + offset, len);
        if (r)
                return -EFAULT;
        return 0;
@@ -1315,7 +1345,7 @@ int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, const void *data,
        addr = gfn_to_hva(kvm, gfn);
        if (kvm_is_error_hva(addr))
                return -EFAULT;
-       r = copy_to_user((void __user *)addr + offset, data, len);
+       r = __copy_to_user((void __user *)addr + offset, data, len);
        if (r)
                return -EFAULT;
        mark_page_dirty(kvm, gfn);
@@ -1375,7 +1405,7 @@ int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
        if (kvm_is_error_hva(ghc->hva))
                return -EFAULT;
 
-       r = copy_to_user((void __user *)ghc->hva, data, len);
+       r = __copy_to_user((void __user *)ghc->hva, data, len);
        if (r)
                return -EFAULT;
        mark_page_dirty_in_slot(kvm, ghc->memslot, ghc->gpa >> PAGE_SHIFT);
@@ -1416,7 +1446,7 @@ void mark_page_dirty_in_slot(struct kvm *kvm, struct kvm_memory_slot *memslot,
        if (memslot && memslot->dirty_bitmap) {
                unsigned long rel_gfn = gfn - memslot->base_gfn;
 
-               generic___set_le_bit(rel_gfn, memslot->dirty_bitmap);
+               __set_bit_le(rel_gfn, memslot->dirty_bitmap);
        }
 }
 
@@ -1461,18 +1491,55 @@ void kvm_resched(struct kvm_vcpu *vcpu)
 }
 EXPORT_SYMBOL_GPL(kvm_resched);
 
-void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu)
+void kvm_vcpu_on_spin(struct kvm_vcpu *me)
 {
-       ktime_t expires;
-       DEFINE_WAIT(wait);
-
-       prepare_to_wait(&vcpu->wq, &wait, TASK_INTERRUPTIBLE);
-
-       /* Sleep for 100 us, and hope lock-holder got scheduled */
-       expires = ktime_add_ns(ktime_get(), 100000UL);
-       schedule_hrtimeout(&expires, HRTIMER_MODE_ABS);
+       struct kvm *kvm = me->kvm;
+       struct kvm_vcpu *vcpu;
+       int last_boosted_vcpu = me->kvm->last_boosted_vcpu;
+       int yielded = 0;
+       int pass;
+       int i;
 
-       finish_wait(&vcpu->wq, &wait);
+       /*
+        * We boost the priority of a VCPU that is runnable but not
+        * currently running, because it got preempted by something
+        * else and called schedule in __vcpu_run.  Hopefully that
+        * VCPU is holding the lock that we need and will release it.
+        * We approximate round-robin by starting at the last boosted VCPU.
+        */
+       for (pass = 0; pass < 2 && !yielded; pass++) {
+               kvm_for_each_vcpu(i, vcpu, kvm) {
+                       struct task_struct *task = NULL;
+                       struct pid *pid;
+                       if (!pass && i < last_boosted_vcpu) {
+                               i = last_boosted_vcpu;
+                               continue;
+                       } else if (pass && i > last_boosted_vcpu)
+                               break;
+                       if (vcpu == me)
+                               continue;
+                       if (waitqueue_active(&vcpu->wq))
+                               continue;
+                       rcu_read_lock();
+                       pid = rcu_dereference(vcpu->pid);
+                       if (pid)
+                               task = get_pid_task(vcpu->pid, PIDTYPE_PID);
+                       rcu_read_unlock();
+                       if (!task)
+                               continue;
+                       if (task->flags & PF_VCPU) {
+                               put_task_struct(task);
+                               continue;
+                       }
+                       if (yield_to(task, 1)) {
+                               put_task_struct(task);
+                               kvm->last_boosted_vcpu = i;
+                               yielded = 1;
+                               break;
+                       }
+                       put_task_struct(task);
+               }
+       }
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_on_spin);
 
@@ -2117,9 +2184,9 @@ static void hardware_enable_nolock(void *junk)
 
 static void hardware_enable(void *junk)
 {
-       spin_lock(&kvm_lock);
+       raw_spin_lock(&kvm_lock);
        hardware_enable_nolock(junk);
-       spin_unlock(&kvm_lock);
+       raw_spin_unlock(&kvm_lock);
 }
 
 static void hardware_disable_nolock(void *junk)
@@ -2134,9 +2201,9 @@ static void hardware_disable_nolock(void *junk)
 
 static void hardware_disable(void *junk)
 {
-       spin_lock(&kvm_lock);
+       raw_spin_lock(&kvm_lock);
        hardware_disable_nolock(junk);
-       spin_unlock(&kvm_lock);
+       raw_spin_unlock(&kvm_lock);
 }
 
 static void hardware_disable_all_nolock(void)
@@ -2150,16 +2217,16 @@ static void hardware_disable_all_nolock(void)
 
 static void hardware_disable_all(void)
 {
-       spin_lock(&kvm_lock);
+       raw_spin_lock(&kvm_lock);
        hardware_disable_all_nolock();
-       spin_unlock(&kvm_lock);
+       raw_spin_unlock(&kvm_lock);
 }
 
 static int hardware_enable_all(void)
 {
        int r = 0;
 
-       spin_lock(&kvm_lock);
+       raw_spin_lock(&kvm_lock);
 
        kvm_usage_count++;
        if (kvm_usage_count == 1) {
@@ -2172,7 +2239,7 @@ static int hardware_enable_all(void)
                }
        }
 
-       spin_unlock(&kvm_lock);
+       raw_spin_unlock(&kvm_lock);
 
        return r;
 }
@@ -2334,10 +2401,10 @@ static int vm_stat_get(void *_offset, u64 *val)
        struct kvm *kvm;
 
        *val = 0;
-       spin_lock(&kvm_lock);
+       raw_spin_lock(&kvm_lock);
        list_for_each_entry(kvm, &vm_list, vm_list)
                *val += *(u32 *)((void *)kvm + offset);
-       spin_unlock(&kvm_lock);
+       raw_spin_unlock(&kvm_lock);
        return 0;
 }
 
@@ -2351,12 +2418,12 @@ static int vcpu_stat_get(void *_offset, u64 *val)
        int i;
 
        *val = 0;
-       spin_lock(&kvm_lock);
+       raw_spin_lock(&kvm_lock);
        list_for_each_entry(kvm, &vm_list, vm_list)
                kvm_for_each_vcpu(i, vcpu, kvm)
                        *val += *(u32 *)((void *)vcpu + offset);
 
-       spin_unlock(&kvm_lock);
+       raw_spin_unlock(&kvm_lock);
        return 0;
 }
 
@@ -2387,33 +2454,26 @@ static void kvm_exit_debug(void)
        debugfs_remove(kvm_debugfs_dir);
 }
 
-static int kvm_suspend(struct sys_device *dev, pm_message_t state)
+static int kvm_suspend(void)
 {
        if (kvm_usage_count)
                hardware_disable_nolock(NULL);
        return 0;
 }
 
-static int kvm_resume(struct sys_device *dev)
+static void kvm_resume(void)
 {
        if (kvm_usage_count) {
-               WARN_ON(spin_is_locked(&kvm_lock));
+               WARN_ON(raw_spin_is_locked(&kvm_lock));
                hardware_enable_nolock(NULL);
        }
-       return 0;
 }
 
-static struct sysdev_class kvm_sysdev_class = {
-       .name = "kvm",
+static struct syscore_ops kvm_syscore_ops = {
        .suspend = kvm_suspend,
        .resume = kvm_resume,
 };
 
-static struct sys_device kvm_sysdev = {
-       .id = 0,
-       .cls = &kvm_sysdev_class,
-};
-
 struct page *bad_page;
 pfn_t bad_pfn;
 
@@ -2497,14 +2557,6 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
                goto out_free_2;
        register_reboot_notifier(&kvm_reboot_notifier);
 
-       r = sysdev_class_register(&kvm_sysdev_class);
-       if (r)
-               goto out_free_3;
-
-       r = sysdev_register(&kvm_sysdev);
-       if (r)
-               goto out_free_4;
-
        /* A kmem cache lets us meet the alignment requirements of fx_save. */
        if (!vcpu_align)
                vcpu_align = __alignof__(struct kvm_vcpu);
@@ -2512,7 +2564,7 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
                                           0, NULL);
        if (!kvm_vcpu_cache) {
                r = -ENOMEM;
-               goto out_free_5;
+               goto out_free_3;
        }
 
        r = kvm_async_pf_init();
@@ -2529,6 +2581,8 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
                goto out_unreg;
        }
 
+       register_syscore_ops(&kvm_syscore_ops);
+
        kvm_preempt_ops.sched_in = kvm_sched_in;
        kvm_preempt_ops.sched_out = kvm_sched_out;
 
@@ -2540,10 +2594,6 @@ out_unreg:
        kvm_async_pf_deinit();
 out_free:
        kmem_cache_destroy(kvm_vcpu_cache);
-out_free_5:
-       sysdev_unregister(&kvm_sysdev);
-out_free_4:
-       sysdev_class_unregister(&kvm_sysdev_class);
 out_free_3:
        unregister_reboot_notifier(&kvm_reboot_notifier);
        unregister_cpu_notifier(&kvm_cpu_notifier);
@@ -2571,8 +2621,7 @@ void kvm_exit(void)
        misc_deregister(&kvm_dev);
        kmem_cache_destroy(kvm_vcpu_cache);
        kvm_async_pf_deinit();
-       sysdev_unregister(&kvm_sysdev);
-       sysdev_class_unregister(&kvm_sysdev_class);
+       unregister_syscore_ops(&kvm_syscore_ops);
        unregister_reboot_notifier(&kvm_reboot_notifier);
        unregister_cpu_notifier(&kvm_cpu_notifier);
        on_each_cpu(hardware_disable_nolock, NULL, 1);