Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "Four security fixes for KVM on x86.  Thanks to Andrew Honig and Lars
  Bull from Google for reporting them"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: fix guest-initiated crash with x2apic (CVE-2013-6376)
  KVM: x86: Convert vapic synchronization to _cached functions (CVE-2013-6368)
  KVM: x86: Fix potential divide by 0 in lapic (CVE-2013-6367)
  KVM: Improve create VCPU parameter (CVE-2013-4587)

3 files changed, 24 insertions, 55 deletions

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 5439117d5c4c..dec48bfaddb8 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -143,6 +143,8 @@ static inline int kvm_apic_id(struct kvm_lapic *apic)
         return (kvm_apic_get_reg(apic, APIC_ID) >> 24) & 0xff;
 }
 
+#define KVM_X2APIC_CID_BITS 0
+
 static void recalculate_apic_map(struct kvm *kvm)
 {
         struct kvm_apic_map *new, *old = NULL;
@@ -180,7 +182,8 @@ static void recalculate_apic_map(struct kvm *kvm)
                 if (apic_x2apic_mode(apic)) {
                         new->ldr_bits = 32;
                         new->cid_shift = 16;
-                        new->cid_mask = new->lid_mask = 0xffff;
+                        new->cid_mask = (1 << KVM_X2APIC_CID_BITS) - 1;
+                        new->lid_mask = 0xffff;
                 } else if (kvm_apic_sw_enabled(apic) &&
                                 !new->cid_mask /* flat mode */ &&
                                 kvm_apic_get_reg(apic, APIC_DFR) == APIC_DFR_CLUSTER) {
@@ -841,7 +844,8 @@ static u32 apic_get_tmcct(struct kvm_lapic *apic)
         ASSERT(apic != NULL);
 
         /* if initial count is 0, current count should also be 0 */
-        if (kvm_apic_get_reg(apic, APIC_TMICT) == 0)
+        if (kvm_apic_get_reg(apic, APIC_TMICT) == 0 ||
+                apic->lapic_timer.period == 0)
                 return 0;
 
         remaining = hrtimer_get_remaining(&apic->lapic_timer.timer);
@@ -1691,7 +1695,6 @@ static void apic_sync_pv_eoi_from_guest(struct kvm_vcpu *vcpu,
 void kvm_lapic_sync_from_vapic(struct kvm_vcpu *vcpu)
 {
         u32 data;
-        void *vapic;
 
         if (test_bit(KVM_APIC_PV_EOI_PENDING, &vcpu->arch.apic_attention))
                 apic_sync_pv_eoi_from_guest(vcpu, vcpu->arch.apic);
@@ -1699,9 +1702,8 @@ void kvm_lapic_sync_from_vapic(struct kvm_vcpu *vcpu)
         if (!test_bit(KVM_APIC_CHECK_VAPIC, &vcpu->arch.apic_attention))
                 return;
 
-        vapic = kmap_atomic(vcpu->arch.apic->vapic_page);
-        data = *(u32 *)(vapic + offset_in_page(vcpu->arch.apic->vapic_addr));
-        kunmap_atomic(vapic);
+        kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.apic->vapic_cache, &data,
+                                sizeof(u32));
 
         apic_set_tpr(vcpu->arch.apic, data & 0xff);
 }
@@ -1737,7 +1739,6 @@ void kvm_lapic_sync_to_vapic(struct kvm_vcpu *vcpu)
         u32 data, tpr;
         int max_irr, max_isr;
         struct kvm_lapic *apic = vcpu->arch.apic;
-        void *vapic;
 
         apic_sync_pv_eoi_to_guest(vcpu, apic);
 
@@ -1753,18 +1754,24 @@ void kvm_lapic_sync_to_vapic(struct kvm_vcpu *vcpu)
                 max_isr = 0;
         data = (tpr & 0xff) | ((max_isr & 0xf0) << 8) | (max_irr << 24);
 
-        vapic = kmap_atomic(vcpu->arch.apic->vapic_page);
-        *(u32 *)(vapic + offset_in_page(vcpu->arch.apic->vapic_addr)) = data;
-        kunmap_atomic(vapic);
+        kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.apic->vapic_cache, &data,
+                                sizeof(u32));
 }
 
-void kvm_lapic_set_vapic_addr(struct kvm_vcpu *vcpu, gpa_t vapic_addr)
+int kvm_lapic_set_vapic_addr(struct kvm_vcpu *vcpu, gpa_t vapic_addr)
 {
-        vcpu->arch.apic->vapic_addr = vapic_addr;
-        if (vapic_addr)
+        if (vapic_addr) {
+                if (kvm_gfn_to_hva_cache_init(vcpu->kvm,
+                                        &vcpu->arch.apic->vapic_cache,
+                                        vapic_addr, sizeof(u32)))
+                        return -EINVAL;
                 __set_bit(KVM_APIC_CHECK_VAPIC, &vcpu->arch.apic_attention);
-        else
+        } else {
                 __clear_bit(KVM_APIC_CHECK_VAPIC, &vcpu->arch.apic_attention);
+        }
+
+        vcpu->arch.apic->vapic_addr = vapic_addr;
+        return 0;
 }
 
 int kvm_x2apic_msr_write(struct kvm_vcpu *vcpu, u32 msr, u64 data)
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index c730ac9fe801..c8b0d0d2da5c 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -34,7 +34,7 @@ struct kvm_lapic {
          */
         void *regs;
         gpa_t vapic_addr;
-        struct page *vapic_page;
+        struct gfn_to_hva_cache vapic_cache;
         unsigned long pending_events;
         unsigned int sipi_vector;
 };
@@ -76,7 +76,7 @@ void kvm_set_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu, u64 data);
 void kvm_apic_write_nodecode(struct kvm_vcpu *vcpu, u32 offset);
 void kvm_apic_set_eoi_accelerated(struct kvm_vcpu *vcpu, int vector);
 
-void kvm_lapic_set_vapic_addr(struct kvm_vcpu *vcpu, gpa_t vapic_addr);
+int kvm_lapic_set_vapic_addr(struct kvm_vcpu *vcpu, gpa_t vapic_addr);
 void kvm_lapic_sync_from_vapic(struct kvm_vcpu *vcpu);
 void kvm_lapic_sync_to_vapic(struct kvm_vcpu *vcpu);
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 21ef1ba184ae..5d004da1e35d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3214,8 +3214,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
                 r = -EFAULT;
                 if (copy_from_user(&va, argp, sizeof va))
                         goto out;
-                r = 0;
-                kvm_lapic_set_vapic_addr(vcpu, va.vapic_addr);
+                r = kvm_lapic_set_vapic_addr(vcpu, va.vapic_addr);
                 break;
         }
         case KVM_X86_SETUP_MCE: {
@@ -5739,36 +5738,6 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu)
                         !kvm_event_needs_reinjection(vcpu);
 }
 
-static int vapic_enter(struct kvm_vcpu *vcpu)
-{
-        struct kvm_lapic *apic = vcpu->arch.apic;
-        struct page *page;
-
-        if (!apic || !apic->vapic_addr)
-                return 0;
-
-        page = gfn_to_page(vcpu->kvm, apic->vapic_addr >> PAGE_SHIFT);
-        if (is_error_page(page))
-                return -EFAULT;
-
-        vcpu->arch.apic->vapic_page = page;
-        return 0;
-}
-
-static void vapic_exit(struct kvm_vcpu *vcpu)
-{
-        struct kvm_lapic *apic = vcpu->arch.apic;
-        int idx;
-
-        if (!apic || !apic->vapic_addr)
-                return;
-
-        idx = srcu_read_lock(&vcpu->kvm->srcu);
-        kvm_release_page_dirty(apic->vapic_page);
-        mark_page_dirty(vcpu->kvm, apic->vapic_addr >> PAGE_SHIFT);
-        srcu_read_unlock(&vcpu->kvm->srcu, idx);
-}
-
 static void update_cr8_intercept(struct kvm_vcpu *vcpu)
 {
         int max_irr, tpr;
@@ -6069,11 +6038,6 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
         struct kvm *kvm = vcpu->kvm;
 
         vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
-        r = vapic_enter(vcpu);
-        if (r) {
-                srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
-                return r;
-        }
 
         r = 1;
         while (r > 0) {
@@ -6132,8 +6096,6 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
 
         srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
 
-        vapic_exit(vcpu);
-
         return r;
 }