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

Pull KVM updates from Paolo Bonzini:
 "One NULL pointer dereference, and two fixes for regressions introduced
  during the merge window.

  The rest are fixes for MIPS, s390 and nested VMX"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvm: x86: Check memopp before dereference (CVE-2016-8630)
  kvm: nVMX: VMCLEAR an active shadow VMCS after last use
  KVM: x86: drop TSC offsetting kvm_x86_ops to fix KVM_GET/SET_CLOCK
  KVM: x86: fix wbinvd_dirty_mask use-after-free
  kvm/x86: Show WRMSR data is in hex
  kvm: nVMX: Fix kernel panics induced by illegal INVEPT/INVVPID types
  KVM: document lock orders
  KVM: fix OOPS on flush_work
  KVM: s390: Fix STHYI buffer alignment for diag224
  KVM: MIPS: Precalculate MMIO load resume PC
  KVM: MIPS: Make ERET handle ERL before EXL
  KVM: MIPS: Fix lazy user ASID regenerate for SMP

4 files changed, 27 insertions, 21 deletions

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 07f58cfc1ab9..bebec370324f 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -293,7 +293,10 @@ struct kvm_vcpu_arch {
         /* Host KSEG0 address of the EI/DI offset */
         void *kseg0_commpage;
 
-        u32 io_gpr;             /* GPR used as IO source/target */
+        /* Resume PC after MMIO completion */
+        unsigned long io_pc;
+        /* GPR used as IO source/target */
+        u32 io_gpr;
 
         struct hrtimer comparecount_timer;
         /* Count timer control KVM register */
@@ -315,8 +318,6 @@ struct kvm_vcpu_arch {
         /* Bitmask of pending exceptions to be cleared */
         unsigned long pending_exceptions_clr;
 
-        u32 pending_load_cause;
-
         /* Save/Restore the entryhi register when are are preempted/scheduled back in */
         unsigned long preempt_entryhi;
 
diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index 8770f32c9e0b..aa0937423e28 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -790,15 +790,15 @@ enum emulation_result kvm_mips_emul_eret(struct kvm_vcpu *vcpu)
         struct mips_coproc *cop0 = vcpu->arch.cop0;
         enum emulation_result er = EMULATE_DONE;
 
-        if (kvm_read_c0_guest_status(cop0) & ST0_EXL) {
+        if (kvm_read_c0_guest_status(cop0) & ST0_ERL) {
+                kvm_clear_c0_guest_status(cop0, ST0_ERL);
+                vcpu->arch.pc = kvm_read_c0_guest_errorepc(cop0);
+        } else if (kvm_read_c0_guest_status(cop0) & ST0_EXL) {
                 kvm_debug("[%#lx] ERET to %#lx\n", vcpu->arch.pc,
                           kvm_read_c0_guest_epc(cop0));
                 kvm_clear_c0_guest_status(cop0, ST0_EXL);
                 vcpu->arch.pc = kvm_read_c0_guest_epc(cop0);
 
-        } else if (kvm_read_c0_guest_status(cop0) & ST0_ERL) {
-                kvm_clear_c0_guest_status(cop0, ST0_ERL);
-                vcpu->arch.pc = kvm_read_c0_guest_errorepc(cop0);
         } else {
                 kvm_err("[%#lx] ERET when MIPS_SR_EXL|MIPS_SR_ERL == 0\n",
                         vcpu->arch.pc);
@@ -1528,13 +1528,25 @@ enum emulation_result kvm_mips_emulate_load(union mips_instruction inst,
                                             struct kvm_vcpu *vcpu)
 {
         enum emulation_result er = EMULATE_DO_MMIO;
+        unsigned long curr_pc;
         u32 op, rt;
         u32 bytes;
 
         rt = inst.i_format.rt;
         op = inst.i_format.opcode;
 
-        vcpu->arch.pending_load_cause = cause;
+        /*
+         * Find the resume PC now while we have safe and easy access to the
+         * prior branch instruction, and save it for
+         * kvm_mips_complete_mmio_load() to restore later.
+         */
+        curr_pc = vcpu->arch.pc;
+        er = update_pc(vcpu, cause);
+        if (er == EMULATE_FAIL)
+                return er;
+        vcpu->arch.io_pc = vcpu->arch.pc;
+        vcpu->arch.pc = curr_pc;
+
         vcpu->arch.io_gpr = rt;
 
         switch (op) {
@@ -2494,9 +2506,8 @@ enum emulation_result kvm_mips_complete_mmio_load(struct kvm_vcpu *vcpu,
                 goto done;
         }
 
-        er = update_pc(vcpu, vcpu->arch.pending_load_cause);
-        if (er == EMULATE_FAIL)
-                return er;
+        /* Restore saved resume PC */
+        vcpu->arch.pc = vcpu->arch.io_pc;
 
         switch (run->mmio.len) {
         case 4:
@@ -2518,11 +2529,6 @@ enum emulation_result kvm_mips_complete_mmio_load(struct kvm_vcpu *vcpu,
                 break;
         }
 
-        if (vcpu->arch.pending_load_cause & CAUSEF_BD)
-                kvm_debug("[%#lx] Completing %d byte BD Load to gpr %d (0x%08lx) type %d\n",
-                          vcpu->arch.pc, run->mmio.len, vcpu->arch.io_gpr, *gpr,
-                          vcpu->mmio_needed);
-
 done:
         return er;
 }
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 622037d851a3..06a60b19acfb 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -426,7 +426,7 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
 static void kvm_mips_check_asids(struct kvm_vcpu *vcpu)
 {
         struct mips_coproc *cop0 = vcpu->arch.cop0;
-        int cpu = smp_processor_id();
+        int i, cpu = smp_processor_id();
         unsigned int gasid;
 
         /*
@@ -442,6 +442,9 @@ static void kvm_mips_check_asids(struct kvm_vcpu *vcpu)
                                                 vcpu);
                         vcpu->arch.guest_user_asid[cpu] =
                                 vcpu->arch.guest_user_mm.context.asid[cpu];
+                        for_each_possible_cpu(i)
+                                if (i != cpu)
+                                        vcpu->arch.guest_user_asid[cpu] = 0;
                         vcpu->arch.last_user_gasid = gasid;
                 }
         }
diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
index 03883ba806e2..3b677c851be0 100644
--- a/arch/mips/kvm/mmu.c
+++ b/arch/mips/kvm/mmu.c
@@ -260,13 +260,9 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
         if ((vcpu->arch.guest_user_asid[cpu] ^ asid_cache(cpu)) &
                                                 asid_version_mask(cpu)) {
-                u32 gasid = kvm_read_c0_guest_entryhi(vcpu->arch.cop0) &
-                                KVM_ENTRYHI_ASID;
-
                 kvm_get_new_mmu_context(&vcpu->arch.guest_user_mm, cpu, vcpu);
                 vcpu->arch.guest_user_asid[cpu] =
                     vcpu->arch.guest_user_mm.context.asid[cpu];
-                vcpu->arch.last_user_gasid = gasid;
                 newasid++;
 
                 kvm_debug("[%d]: cpu_context: %#lx\n", cpu,