KVM: MMU: Concurrent guest walkers
[sfrench/cifs-2.6.git] / arch / x86 / kvm / x86.c
index 1f48ec871035eea14c4dd7bd186b63b2daf8fab0..e3b3141db13caf4c63876df8eedb43a5bf1272e6 100644 (file)
@@ -181,7 +181,7 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3)
        int ret;
        u64 pdpte[ARRAY_SIZE(vcpu->arch.pdptrs)];
 
-       mutex_lock(&vcpu->kvm->lock);
+       down_read(&current->mm->mmap_sem);
        ret = kvm_read_guest_page(vcpu->kvm, pdpt_gfn, pdpte,
                                  offset * sizeof(u64), sizeof(pdpte));
        if (ret < 0) {
@@ -198,7 +198,7 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3)
 
        memcpy(vcpu->arch.pdptrs, pdpte, sizeof(vcpu->arch.pdptrs));
 out:
-       mutex_unlock(&vcpu->kvm->lock);
+       up_read(&current->mm->mmap_sem);
 
        return ret;
 }
@@ -212,13 +212,13 @@ static bool pdptrs_changed(struct kvm_vcpu *vcpu)
        if (is_long_mode(vcpu) || !is_pae(vcpu))
                return false;
 
-       mutex_lock(&vcpu->kvm->lock);
+       down_read(&current->mm->mmap_sem);
        r = kvm_read_guest(vcpu->kvm, vcpu->arch.cr3 & ~31u, pdpte, sizeof(pdpte));
        if (r < 0)
                goto out;
        changed = memcmp(pdpte, vcpu->arch.pdptrs, sizeof(pdpte)) != 0;
 out:
-       mutex_unlock(&vcpu->kvm->lock);
+       up_read(&current->mm->mmap_sem);
 
        return changed;
 }
@@ -278,9 +278,7 @@ void set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
        kvm_x86_ops->set_cr0(vcpu, cr0);
        vcpu->arch.cr0 = cr0;
 
-       mutex_lock(&vcpu->kvm->lock);
        kvm_mmu_reset_context(vcpu);
-       mutex_unlock(&vcpu->kvm->lock);
        return;
 }
 EXPORT_SYMBOL_GPL(set_cr0);
@@ -320,9 +318,7 @@ void set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
        }
        kvm_x86_ops->set_cr4(vcpu, cr4);
        vcpu->arch.cr4 = cr4;
-       mutex_lock(&vcpu->kvm->lock);
        kvm_mmu_reset_context(vcpu);
-       mutex_unlock(&vcpu->kvm->lock);
 }
 EXPORT_SYMBOL_GPL(set_cr4);
 
@@ -360,7 +356,7 @@ void set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
                 */
        }
 
-       mutex_lock(&vcpu->kvm->lock);
+       down_read(&current->mm->mmap_sem);
        /*
         * Does the new cr3 value map to physical memory? (Note, we
         * catch an invalid cr3 even in real-mode, because it would
@@ -376,7 +372,7 @@ void set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
                vcpu->arch.cr3 = cr3;
                vcpu->arch.mmu.new_cr3(vcpu);
        }
-       mutex_unlock(&vcpu->kvm->lock);
+       up_read(&current->mm->mmap_sem);
 }
 EXPORT_SYMBOL_GPL(set_cr3);
 
@@ -1211,12 +1207,12 @@ static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm,
        if (kvm_nr_mmu_pages < KVM_MIN_ALLOC_MMU_PAGES)
                return -EINVAL;
 
-       mutex_lock(&kvm->lock);
+       down_write(&current->mm->mmap_sem);
 
        kvm_mmu_change_mmu_pages(kvm, kvm_nr_mmu_pages);
        kvm->arch.n_requested_mmu_pages = kvm_nr_mmu_pages;
 
-       mutex_unlock(&kvm->lock);
+       up_write(&current->mm->mmap_sem);
        return 0;
 }
 
@@ -1265,7 +1261,7 @@ static int kvm_vm_ioctl_set_memory_alias(struct kvm *kvm,
            < alias->target_phys_addr)
                goto out;
 
-       mutex_lock(&kvm->lock);
+       down_write(&current->mm->mmap_sem);
 
        p = &kvm->arch.aliases[alias->slot];
        p->base_gfn = alias->guest_phys_addr >> PAGE_SHIFT;
@@ -1279,7 +1275,7 @@ static int kvm_vm_ioctl_set_memory_alias(struct kvm *kvm,
 
        kvm_mmu_zap_all(kvm);
 
-       mutex_unlock(&kvm->lock);
+       up_write(&current->mm->mmap_sem);
 
        return 0;
 
@@ -1355,7 +1351,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
        struct kvm_memory_slot *memslot;
        int is_dirty = 0;
 
-       mutex_lock(&kvm->lock);
+       down_write(&current->mm->mmap_sem);
 
        r = kvm_get_dirty_log(kvm, log, &is_dirty);
        if (r)
@@ -1371,7 +1367,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
        }
        r = 0;
 out:
-       mutex_unlock(&kvm->lock);
+       up_write(&current->mm->mmap_sem);
        return r;
 }
 
@@ -1565,25 +1561,32 @@ int emulator_read_std(unsigned long addr,
                             struct kvm_vcpu *vcpu)
 {
        void *data = val;
+       int r = X86EMUL_CONTINUE;
 
+       down_read(&current->mm->mmap_sem);
        while (bytes) {
                gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
                unsigned offset = addr & (PAGE_SIZE-1);
                unsigned tocopy = min(bytes, (unsigned)PAGE_SIZE - offset);
                int ret;
 
-               if (gpa == UNMAPPED_GVA)
-                       return X86EMUL_PROPAGATE_FAULT;
+               if (gpa == UNMAPPED_GVA) {
+                       r = X86EMUL_PROPAGATE_FAULT;
+                       goto out;
+               }
                ret = kvm_read_guest(vcpu->kvm, gpa, data, tocopy);
-               if (ret < 0)
-                       return X86EMUL_UNHANDLEABLE;
+               if (ret < 0) {
+                       r = X86EMUL_UNHANDLEABLE;
+                       goto out;
+               }
 
                bytes -= tocopy;
                data += tocopy;
                addr += tocopy;
        }
-
-       return X86EMUL_CONTINUE;
+out:
+       up_read(&current->mm->mmap_sem);
+       return r;
 }
 EXPORT_SYMBOL_GPL(emulator_read_std);
 
@@ -1601,7 +1604,9 @@ static int emulator_read_emulated(unsigned long addr,
                return X86EMUL_CONTINUE;
        }
 
+       down_read(&current->mm->mmap_sem);
        gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
+       up_read(&current->mm->mmap_sem);
 
        /* For APIC access vmexit */
        if ((gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
@@ -1617,11 +1622,14 @@ mmio:
        /*
         * Is this MMIO handled locally?
         */
+       mutex_lock(&vcpu->kvm->lock);
        mmio_dev = vcpu_find_mmio_dev(vcpu, gpa);
        if (mmio_dev) {
                kvm_iodevice_read(mmio_dev, gpa, bytes, val);
+               mutex_unlock(&vcpu->kvm->lock);
                return X86EMUL_CONTINUE;
        }
+       mutex_unlock(&vcpu->kvm->lock);
 
        vcpu->mmio_needed = 1;
        vcpu->mmio_phys_addr = gpa;
@@ -1636,10 +1644,14 @@ static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
 {
        int ret;
 
+       down_read(&current->mm->mmap_sem);
        ret = kvm_write_guest(vcpu->kvm, gpa, val, bytes);
-       if (ret < 0)
+       if (ret < 0) {
+               up_read(&current->mm->mmap_sem);
                return 0;
+       }
        kvm_mmu_pte_write(vcpu, gpa, val, bytes);
+       up_read(&current->mm->mmap_sem);
        return 1;
 }
 
@@ -1649,7 +1661,11 @@ static int emulator_write_emulated_onepage(unsigned long addr,
                                           struct kvm_vcpu *vcpu)
 {
        struct kvm_io_device *mmio_dev;
-       gpa_t                 gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
+       gpa_t                 gpa;
+
+       down_read(&current->mm->mmap_sem);
+       gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
+       up_read(&current->mm->mmap_sem);
 
        if (gpa == UNMAPPED_GVA) {
                kvm_inject_page_fault(vcpu, addr, 2);
@@ -1667,11 +1683,14 @@ mmio:
        /*
         * Is this MMIO handled locally?
         */
+       mutex_lock(&vcpu->kvm->lock);
        mmio_dev = vcpu_find_mmio_dev(vcpu, gpa);
        if (mmio_dev) {
                kvm_iodevice_write(mmio_dev, gpa, bytes, val);
+               mutex_unlock(&vcpu->kvm->lock);
                return X86EMUL_CONTINUE;
        }
+       mutex_unlock(&vcpu->kvm->lock);
 
        vcpu->mmio_needed = 1;
        vcpu->mmio_phys_addr = gpa;
@@ -1718,11 +1737,14 @@ static int emulator_cmpxchg_emulated(unsigned long addr,
 #ifndef CONFIG_X86_64
        /* guests cmpxchg8b have to be emulated atomically */
        if (bytes == 8) {
-               gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
+               gpa_t gpa;
                struct page *page;
                char *addr;
                u64 val;
 
+               down_read(&current->mm->mmap_sem);
+               gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
+
                if (gpa == UNMAPPED_GVA ||
                   (gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
                        goto emul_write;
@@ -1736,8 +1758,9 @@ static int emulator_cmpxchg_emulated(unsigned long addr,
                set_64bit((u64 *)(addr + offset_in_page(gpa)), val);
                kunmap_atomic(addr, KM_USER0);
                kvm_release_page_dirty(page);
+       emul_write:
+               up_read(&current->mm->mmap_sem);
        }
-emul_write:
 #endif
 
        return emulator_write_emulated(addr, new, bytes, vcpu);
@@ -2118,10 +2141,10 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
                kvm_x86_ops->skip_emulated_instruction(vcpu);
 
        for (i = 0; i < nr_pages; ++i) {
-               mutex_lock(&vcpu->kvm->lock);
+               down_read(&current->mm->mmap_sem);
                page = gva_to_page(vcpu, address + i * PAGE_SIZE);
                vcpu->arch.pio.guest_pages[i] = page;
-               mutex_unlock(&vcpu->kvm->lock);
+               up_read(&current->mm->mmap_sem);
                if (!page) {
                        kvm_inject_gp(vcpu, 0);
                        free_pio_guest_pages(vcpu);
@@ -2247,7 +2270,6 @@ int kvm_fix_hypercall(struct kvm_vcpu *vcpu)
        char instruction[3];
        int ret = 0;
 
-       mutex_lock(&vcpu->kvm->lock);
 
        /*
         * Blow out the MMU to ensure that no other VCPU has an active mapping
@@ -2262,8 +2284,6 @@ int kvm_fix_hypercall(struct kvm_vcpu *vcpu)
            != X86EMUL_CONTINUE)
                ret = -EFAULT;
 
-       mutex_unlock(&vcpu->kvm->lock);
-
        return ret;
 }
 
@@ -2447,8 +2467,10 @@ static void vapic_enter(struct kvm_vcpu *vcpu)
        if (!apic || !apic->vapic_addr)
                return;
 
+       down_read(&current->mm->mmap_sem);
        page = gfn_to_page(vcpu->kvm, apic->vapic_addr >> PAGE_SHIFT);
        vcpu->arch.apic->vapic_page = page;
+       up_read(&current->mm->mmap_sem);
 }
 
 static void vapic_exit(struct kvm_vcpu *vcpu)
@@ -2910,13 +2932,13 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
        gpa_t gpa;
 
        vcpu_load(vcpu);
-       mutex_lock(&vcpu->kvm->lock);
+       down_read(&current->mm->mmap_sem);
        gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, vaddr);
+       up_read(&current->mm->mmap_sem);
        tr->physical_address = gpa;
        tr->valid = gpa != UNMAPPED_GVA;
        tr->writeable = 1;
        tr->usermode = 0;
-       mutex_unlock(&vcpu->kvm->lock);
        vcpu_put(vcpu);
 
        return 0;
@@ -3185,13 +3207,11 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
         */
        if (!user_alloc) {
                if (npages && !old.rmap) {
-                       down_write(&current->mm->mmap_sem);
                        memslot->userspace_addr = do_mmap(NULL, 0,
                                                     npages * PAGE_SIZE,
                                                     PROT_READ | PROT_WRITE,
                                                     MAP_SHARED | MAP_ANONYMOUS,
                                                     0);
-                       up_write(&current->mm->mmap_sem);
 
                        if (IS_ERR((void *)memslot->userspace_addr))
                                return PTR_ERR((void *)memslot->userspace_addr);
@@ -3199,10 +3219,8 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
                        if (!old.user_alloc && old.rmap) {
                                int ret;
 
-                               down_write(&current->mm->mmap_sem);
                                ret = do_munmap(current->mm, old.userspace_addr,
                                                old.npages * PAGE_SIZE);
-                               up_write(&current->mm->mmap_sem);
                                if (ret < 0)
                                        printk(KERN_WARNING
                                       "kvm_vm_ioctl_set_memory_region: "