Merge tag 'kvm-s390-master-4.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git...

KVM: s390: Fixes for 4.8 (via kvm/master)

Here are two fixes found by fuzzing of the ioctl interface.
Both cases can trigger a WARN_ON_ONCE from user space.

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index d94bb9093ead7d10641aecfaed668d0c3ee3fa39..75f130ef650413036625c59f34ab864c1649052e 100644 (file)
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -1009,9 +1009,13 @@ long kvm_arch_vm_ioctl(struct file *filp,
 
        switch (ioctl) {
        case KVM_CREATE_IRQCHIP: {
+               int ret;
                if (!vgic_present)
                        return -ENXIO;
-               return kvm_vgic_create(kvm, KVM_DEV_TYPE_ARM_VGIC_V2);
+               mutex_lock(&kvm->lock);
+               ret = kvm_vgic_create(kvm, KVM_DEV_TYPE_ARM_VGIC_V2);
+               mutex_unlock(&kvm->lock);
+               return ret;
        }
        case KVM_ARM_SET_DEVICE_ADDR: {
                struct kvm_arm_device_addr dev_addr;

diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index 6eb52b9c98183b95134710c22187b1a6f0225ef9..e788515f766b46cefb2a36dfc95ab6bfcec6e8e3 100644 (file)
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -1642,8 +1642,14 @@ enum emulation_result kvm_mips_emulate_cache(union mips_instruction inst,
 
        preempt_disable();
        if (KVM_GUEST_KSEGX(va) == KVM_GUEST_KSEG0) {
-               if (kvm_mips_host_tlb_lookup(vcpu, va) < 0)
-                       kvm_mips_handle_kseg0_tlb_fault(va, vcpu);
+               if (kvm_mips_host_tlb_lookup(vcpu, va) < 0 &&
+                   kvm_mips_handle_kseg0_tlb_fault(va, vcpu)) {
+                       kvm_err("%s: handling mapped kseg0 tlb fault for %lx, vcpu: %p, ASID: %#lx\n",
+                               __func__, va, vcpu, read_c0_entryhi());
+                       er = EMULATE_FAIL;
+                       preempt_enable();
+                       goto done;
+               }
        } else if ((KVM_GUEST_KSEGX(va) < KVM_GUEST_KSEG0) ||
                   KVM_GUEST_KSEGX(va) == KVM_GUEST_KSEG23) {
                int index;
@@ -1680,12 +1686,18 @@ enum emulation_result kvm_mips_emulate_cache(union mips_instruction inst,
                                                                run, vcpu);
                                preempt_enable();
                                goto dont_update_pc;
-                       } else {
-                               /*
-                                * We fault an entry from the guest tlb to the
-                                * shadow host TLB
-                                */
-                               kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb);
+                       }
+                       /*
+                        * We fault an entry from the guest tlb to the
+                        * shadow host TLB
+                        */
+                       if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb)) {
+                               kvm_err("%s: handling mapped seg tlb fault for %lx, index: %u, vcpu: %p, ASID: %#lx\n",
+                                       __func__, va, index, vcpu,
+                                       read_c0_entryhi());
+                               er = EMULATE_FAIL;
+                               preempt_enable();
+                               goto done;
                        }
                }
        } else {
@@ -2659,7 +2671,12 @@ enum emulation_result kvm_mips_handle_tlbmiss(u32 cause,
                         * OK we have a Guest TLB entry, now inject it into the
                         * shadow host TLB
                         */
-                       kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb);
+                       if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb)) {
+                               kvm_err("%s: handling mapped seg tlb fault for %lx, index: %u, vcpu: %p, ASID: %#lx\n",
+                                       __func__, va, index, vcpu,
+                                       read_c0_entryhi());
+                               er = EMULATE_FAIL;
+                       }
                }
        }
 

diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
index 57319ee57c4fdd1aada66e1648adc3981edf9dc3..6cfdcf55572d6aaa747998683f06bbf7f5a3e5ab 100644 (file)
--- a/arch/mips/kvm/mmu.c
+++ b/arch/mips/kvm/mmu.c
@@ -99,7 +99,7 @@ int kvm_mips_handle_kseg0_tlb_fault(unsigned long badvaddr,
        }
 
        gfn = (KVM_GUEST_CPHYSADDR(badvaddr) >> PAGE_SHIFT);
-       if (gfn >= kvm->arch.guest_pmap_npages) {
+       if ((gfn | 1) >= kvm->arch.guest_pmap_npages) {
                kvm_err("%s: Invalid gfn: %#llx, BadVaddr: %#lx\n", __func__,
                        gfn, badvaddr);
                kvm_mips_dump_host_tlbs();
@@ -138,35 +138,49 @@ int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu,
        unsigned long entryhi = 0, entrylo0 = 0, entrylo1 = 0;
        struct kvm *kvm = vcpu->kvm;
        kvm_pfn_t pfn0, pfn1;
+       gfn_t gfn0, gfn1;
+       long tlb_lo[2];
        int ret;
 
-       if ((tlb->tlb_hi & VPN2_MASK) == 0) {
-               pfn0 = 0;
-               pfn1 = 0;
-       } else {
-               if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb->tlb_lo[0])
-                                          >> PAGE_SHIFT) < 0)
-                       return -1;
-
-               if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb->tlb_lo[1])
-                                          >> PAGE_SHIFT) < 0)
-                       return -1;
-
-               pfn0 = kvm->arch.guest_pmap[
-                       mips3_tlbpfn_to_paddr(tlb->tlb_lo[0]) >> PAGE_SHIFT];
-               pfn1 = kvm->arch.guest_pmap[
-                       mips3_tlbpfn_to_paddr(tlb->tlb_lo[1]) >> PAGE_SHIFT];
+       tlb_lo[0] = tlb->tlb_lo[0];
+       tlb_lo[1] = tlb->tlb_lo[1];
+
+       /*
+        * The commpage address must not be mapped to anything else if the guest
+        * TLB contains entries nearby, or commpage accesses will break.
+        */
+       if (!((tlb->tlb_hi ^ KVM_GUEST_COMMPAGE_ADDR) &
+                       VPN2_MASK & (PAGE_MASK << 1)))
+               tlb_lo[(KVM_GUEST_COMMPAGE_ADDR >> PAGE_SHIFT) & 1] = 0;
+
+       gfn0 = mips3_tlbpfn_to_paddr(tlb_lo[0]) >> PAGE_SHIFT;
+       gfn1 = mips3_tlbpfn_to_paddr(tlb_lo[1]) >> PAGE_SHIFT;
+       if (gfn0 >= kvm->arch.guest_pmap_npages ||
+           gfn1 >= kvm->arch.guest_pmap_npages) {
+               kvm_err("%s: Invalid gfn: [%#llx, %#llx], EHi: %#lx\n",
+                       __func__, gfn0, gfn1, tlb->tlb_hi);
+               kvm_mips_dump_guest_tlbs(vcpu);
+               return -1;
        }
 
+       if (kvm_mips_map_page(kvm, gfn0) < 0)
+               return -1;
+
+       if (kvm_mips_map_page(kvm, gfn1) < 0)
+               return -1;
+
+       pfn0 = kvm->arch.guest_pmap[gfn0];
+       pfn1 = kvm->arch.guest_pmap[gfn1];
+
        /* Get attributes from the Guest TLB */
        entrylo0 = mips3_paddr_to_tlbpfn(pfn0 << PAGE_SHIFT) |
                ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
-               (tlb->tlb_lo[0] & ENTRYLO_D) |
-               (tlb->tlb_lo[0] & ENTRYLO_V);
+               (tlb_lo[0] & ENTRYLO_D) |
+               (tlb_lo[0] & ENTRYLO_V);
        entrylo1 = mips3_paddr_to_tlbpfn(pfn1 << PAGE_SHIFT) |
                ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
-               (tlb->tlb_lo[1] & ENTRYLO_D) |
-               (tlb->tlb_lo[1] & ENTRYLO_V);
+               (tlb_lo[1] & ENTRYLO_D) |
+               (tlb_lo[1] & ENTRYLO_V);
 
        kvm_debug("@ %#lx tlb_lo0: 0x%08lx tlb_lo1: 0x%08lx\n", vcpu->arch.pc,
                  tlb->tlb_lo[0], tlb->tlb_lo[1]);
@@ -354,9 +368,15 @@ u32 kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu)
                                local_irq_restore(flags);
                                return KVM_INVALID_INST;
                        }
-                       kvm_mips_handle_mapped_seg_tlb_fault(vcpu,
-                                                            &vcpu->arch.
-                                                            guest_tlb[index]);
+                       if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu,
+                                               &vcpu->arch.guest_tlb[index])) {
+                               kvm_err("%s: handling mapped seg tlb fault failed for %p, index: %u, vcpu: %p, ASID: %#lx\n",
+                                       __func__, opc, index, vcpu,
+                                       read_c0_entryhi());
+                               kvm_mips_dump_guest_tlbs(vcpu);
+                               local_irq_restore(flags);
+                               return KVM_INVALID_INST;
+                       }
                        inst = *(opc);
                }
                local_irq_restore(flags);

diff --git a/arch/powerpc/kvm/book3s_xics.c b/arch/powerpc/kvm/book3s_xics.c
index a75ba38a2d81415dfcbe497c27b1329fdd6c8736..05aa11399a7867c1a4148d0f9eb4bf80bca3ee9d 100644 (file)
--- a/arch/powerpc/kvm/book3s_xics.c
+++ b/arch/powerpc/kvm/book3s_xics.c
@@ -1329,20 +1329,16 @@ static int kvmppc_xics_create(struct kvm_device *dev, u32 type)
        xics->kvm = kvm;
 
        /* Already there ? */
-       mutex_lock(&kvm->lock);
        if (kvm->arch.xics)
                ret = -EEXIST;
        else
                kvm->arch.xics = xics;
-       mutex_unlock(&kvm->lock);
 
        if (ret) {
                kfree(xics);
                return ret;
        }
 
-       xics_debugfs_init(xics);
-
 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
        if (cpu_has_feature(CPU_FTR_ARCH_206)) {
                /* Enable real mode support */
@@ -1354,9 +1350,17 @@ static int kvmppc_xics_create(struct kvm_device *dev, u32 type)
        return 0;
 }
 
+static void kvmppc_xics_init(struct kvm_device *dev)
+{
+       struct kvmppc_xics *xics = (struct kvmppc_xics *)dev->private;
+
+       xics_debugfs_init(xics);
+}
+
 struct kvm_device_ops kvm_xics_ops = {
        .name = "kvm-xics",
        .create = kvmppc_xics_create,
+       .init = kvmppc_xics_init,
        .destroy = kvmppc_xics_free,
        .set_attr = xics_set_attr,
        .get_attr = xics_get_attr,

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 01e908ac4a39a7ed65a68a59f097b302a80c3b57..9c28b4d4c90b137ac72acad323ae2785e3d4dcce 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1113,8 +1113,20 @@ struct kvm_device {
 /* create, destroy, and name are mandatory */
 struct kvm_device_ops {
        const char *name;
+
+       /*
+        * create is called holding kvm->lock and any operations not suitable
+        * to do while holding the lock should be deferred to init (see
+        * below).
+        */
        int (*create)(struct kvm_device *dev, u32 type);
 
+       /*
+        * init is called after create if create is successful and is called
+        * outside of holding kvm->lock.
+        */
+       void (*init)(struct kvm_device *dev);
+
        /*
         * Destroy is responsible for freeing dev.
         *

diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index fb4b0a79a9502ba9bcaad7acfdbbf692c5ed5208..83777c1cbae0693c14e1d3f23df927c5cae25fef 100644 (file)
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -73,12 +73,8 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
        int i, vcpu_lock_idx = -1, ret;
        struct kvm_vcpu *vcpu;
 
-       mutex_lock(&kvm->lock);
-
-       if (irqchip_in_kernel(kvm)) {
-               ret = -EEXIST;
-               goto out;
-       }
+       if (irqchip_in_kernel(kvm))
+               return -EEXIST;
 
        /*
         * This function is also called by the KVM_CREATE_IRQCHIP handler,
@@ -87,10 +83,8 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
         * the proper checks already.
         */
        if (type == KVM_DEV_TYPE_ARM_VGIC_V2 &&
-               !kvm_vgic_global_state.can_emulate_gicv2) {
-               ret = -ENODEV;
-               goto out;
-       }
+               !kvm_vgic_global_state.can_emulate_gicv2)
+               return -ENODEV;
 
        /*
         * Any time a vcpu is run, vcpu_load is called which tries to grab the
@@ -138,9 +132,6 @@ out_unlock:
                vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
                mutex_unlock(&vcpu->mutex);
        }
-
-out:
-       mutex_unlock(&kvm->lock);
        return ret;
 }
 

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index cc081ccfcaa3743ca5e0f46dd350bda36bc3ec72..195078225aa5d0c3b3214fd40e0b5f441c5d7518 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -696,6 +696,11 @@ static void kvm_destroy_devices(struct kvm *kvm)
 {
        struct kvm_device *dev, *tmp;
 
+       /*
+        * We do not need to take the kvm->lock here, because nobody else
+        * has a reference to the struct kvm at this point and therefore
+        * cannot access the devices list anyhow.
+        */
        list_for_each_entry_safe(dev, tmp, &kvm->devices, vm_node) {
                list_del(&dev->vm_node);
                dev->ops->destroy(dev);
@@ -2832,19 +2837,28 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
        dev->ops = ops;
        dev->kvm = kvm;
 
+       mutex_lock(&kvm->lock);
        ret = ops->create(dev, cd->type);
        if (ret < 0) {
+               mutex_unlock(&kvm->lock);
                kfree(dev);
                return ret;
        }
+       list_add(&dev->vm_node, &kvm->devices);
+       mutex_unlock(&kvm->lock);
+
+       if (ops->init)
+               ops->init(dev);
 
        ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
        if (ret < 0) {
                ops->destroy(dev);
+               mutex_lock(&kvm->lock);
+               list_del(&dev->vm_node);
+               mutex_unlock(&kvm->lock);
                return ret;
        }
 
-       list_add(&dev->vm_node, &kvm->devices);
        kvm_get_kvm(kvm);
        cd->fd = ret;
        return 0;