[RFC PATCH 11/67] KVM: x86: Use KVM_BUG/KVM_BUG_ON to handle bugs that are fatal to the VM

[isaku . yamahata]

From: Sean Christopherson <sean.j.christopher...@intel.com>

Signed-off-by: Sean Christopherson <sean.j.christopher...@intel.com>
---
 arch/x86/kvm/svm/svm.c |  2 +-
 arch/x86/kvm/vmx/vmx.c | 23 ++++++++++++++---------
 arch/x86/kvm/x86.c     |  4 ++++
 3 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 2f32fd09e259..e001e3c9e4bc 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1452,7 +1452,7 @@ static void svm_cache_reg(struct kvm_vcpu *vcpu, enum 
kvm_reg reg)
                load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu));
                break;
        default:
-               WARN_ON_ONCE(1);
+               KVM_BUG_ON(1, vcpu->kvm);
        }
 }
 
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 47b8357b9751..1c9ad3103c87 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2245,7 +2245,7 @@ static void vmx_cache_reg(struct kvm_vcpu *vcpu, enum 
kvm_reg reg)
                vcpu->arch.cr4 |= vmcs_readl(GUEST_CR4) & guest_owned_bits;
                break;
        default:
-               WARN_ON_ONCE(1);
+               KVM_BUG_ON(1, vcpu->kvm);
                break;
        }
 }
@@ -5006,6 +5006,7 @@ static int handle_cr(struct kvm_vcpu *vcpu)
                        return kvm_complete_insn_gp(vcpu, err);
                case 3:
                        WARN_ON_ONCE(enable_unrestricted_guest);
+
                        err = kvm_set_cr3(vcpu, val);
                        return kvm_complete_insn_gp(vcpu, err);
                case 4:
@@ -5031,14 +5032,13 @@ static int handle_cr(struct kvm_vcpu *vcpu)
                }
                break;
        case 2: /* clts */
-               WARN_ONCE(1, "Guest should always own CR0.TS");
-               vmx_set_cr0(vcpu, kvm_read_cr0_bits(vcpu, ~X86_CR0_TS));
-               trace_kvm_cr_write(0, kvm_read_cr0(vcpu));
-               return kvm_skip_emulated_instruction(vcpu);
+               KVM_BUG(1, vcpu->kvm, "Guest always owns CR0.TS");
+               return -EIO;
        case 1: /*mov from cr*/
                switch (cr) {
                case 3:
                        WARN_ON_ONCE(enable_unrestricted_guest);
+
                        val = kvm_read_cr3(vcpu);
                        kvm_register_write(vcpu, reg, val);
                        trace_kvm_cr_read(cr, val);
@@ -5377,7 +5377,9 @@ static int handle_ept_misconfig(struct kvm_vcpu *vcpu)
 
 static int handle_nmi_window(struct kvm_vcpu *vcpu)
 {
-       WARN_ON_ONCE(!enable_vnmi);
+       if (KVM_BUG_ON(!enable_vnmi, vcpu->kvm))
+               return -EIO;
+
        exec_controls_clearbit(to_vmx(vcpu), CPU_BASED_NMI_WINDOW_EXITING);
        ++vcpu->stat.nmi_window_exits;
        kvm_make_request(KVM_REQ_EVENT, vcpu);
@@ -5950,7 +5952,8 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu, 
fastpath_t exit_fastpath)
         * below) should never happen as that means we incorrectly allowed a
         * nested VM-Enter with an invalid vmcs12.
         */
-       WARN_ON_ONCE(vmx->nested.nested_run_pending);
+       if (KVM_BUG_ON(vmx->nested.nested_run_pending, vcpu->kvm))
+               return -EIO;
 
        /* If guest state is invalid, start emulating */
        if (vmx->emulation_required)
@@ -6300,7 +6303,9 @@ static int vmx_sync_pir_to_irr(struct kvm_vcpu *vcpu)
        int max_irr;
        bool max_irr_updated;
 
-       WARN_ON(!vcpu->arch.apicv_active);
+       if (KVM_BUG_ON(!vcpu->arch.apicv_active, vcpu->kvm))
+               return -EIO;
+
        if (pi_test_on(&vmx->pi_desc)) {
                pi_clear_on(&vmx->pi_desc);
                /*
@@ -6382,7 +6387,7 @@ static void handle_external_interrupt_irqoff(struct 
kvm_vcpu *vcpu)
 {
        u32 intr_info = vmx_get_intr_info(vcpu);
 
-       if (WARN_ONCE(!is_external_intr(intr_info),
+       if (KVM_BUG(!is_external_intr(intr_info), vcpu->kvm,
            "KVM: unexpected VM-Exit interrupt info: 0x%x", intr_info))
                return;
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1d999b57f21a..19b53aedc6c8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8722,6 +8722,10 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
        bool req_immediate_exit = false;
 
        if (kvm_request_pending(vcpu)) {
+               if (kvm_check_request(KVM_REQ_VM_BUGGED, vcpu)) {
+                       r = -EIO;
+                       goto out;
+               }
                if (kvm_check_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu)) {
                        if 
(unlikely(!kvm_x86_ops.nested_ops->get_nested_state_pages(vcpu))) {
                                r = 0;
-- 
2.17.1