diff mbox series

[RFC,v5,19/20] kvm: x86: handle the introspection hypercalls

Message ID 20181220182850.4579-20-alazar@bitdefender.com (mailing list archive)
State New, archived
Headers show
Series VM introspection | expand

Commit Message

Adalbert Lazăr Dec. 20, 2018, 6:28 p.m. UTC 
Two hypercalls (KVM_HC_MEM_MAP, KVM_HC_MEM_UNMAP) are used by the
introspection tool running in a VM to map/unmap memory from the
introspected VM-s.

The third hypercall (KVM_HC_XEN_HVM_OP) is used by the code residing
inside the introspected guest to call the introspection tool and to report
certain details about its operation. For example, a classic antimalware
remediation tool can report what it has found during a scan.

Signed-off-by: Mihai Donțu <mdontu@bitdefender.com>
Signed-off-by: Mircea Cîrjaliu <mcirjaliu@bitdefender.com>
---
 arch/x86/kvm/x86.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 89e508ca7c8b..6d5f801e4797 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7027,11 +7027,14 @@  int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
 {
 	unsigned long nr, a0, a1, a2, a3, ret;
 	int op_64_bit;
+	bool kvmi_hc;
 
-	if (kvm_hv_hypercall_enabled(vcpu->kvm))
+	nr = kvm_register_read(vcpu, VCPU_REGS_RAX);
+	kvmi_hc = (u32)nr == KVM_HC_XEN_HVM_OP;
+
+	if (kvm_hv_hypercall_enabled(vcpu->kvm) && !kvmi_hc)
 		return kvm_hv_hypercall(vcpu);
 
-	nr = kvm_register_read(vcpu, VCPU_REGS_RAX);
 	a0 = kvm_register_read(vcpu, VCPU_REGS_RBX);
 	a1 = kvm_register_read(vcpu, VCPU_REGS_RCX);
 	a2 = kvm_register_read(vcpu, VCPU_REGS_RDX);
@@ -7048,7 +7051,7 @@  int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
 		a3 &= 0xFFFFFFFF;
 	}
 
-	if (kvm_x86_ops->get_cpl(vcpu) != 0) {
+	if (kvm_x86_ops->get_cpl(vcpu) != 0 && !kvmi_hc) {
 		ret = -KVM_EPERM;
 		goto out;
 	}
@@ -7069,6 +7072,19 @@  int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
 		ret = kvm_pv_send_ipi(vcpu->kvm, a0, a1, a2, a3, op_64_bit);
 		break;
 #endif
+#ifdef CONFIG_KVM_INTROSPECTION
+	case KVM_HC_MEM_MAP:
+		ret = kvmi_host_mem_map(vcpu, (gva_t)a0, (gpa_t)a1, (gpa_t)a2);
+		break;
+	case KVM_HC_MEM_UNMAP:
+		ret = kvmi_host_mem_unmap(vcpu, (gpa_t)a0);
+		break;
+	case KVM_HC_XEN_HVM_OP:
+		ret = 0;
+		if (!kvmi_hypercall_event(vcpu))
+			ret = -KVM_ENOSYS;
+		break;
+#endif /* CONFIG_KVM_INTROSPECTION */
 	default:
 		ret = -KVM_ENOSYS;
 		break;