[RFC,v4,17/18] kvm: x86: handle the introspection hypercalls

Commit Message

Adalbert Lazăr Dec. 18, 2017, 7:06 p.m. UTC

From: Adalbert Lazar <[e-mail]>

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: Mircea Cîrjaliu <[e-mail]>
Signed-off-by: Nicușor Cîțu <[e-mail]>
---
 arch/x86/kvm/x86.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 271028ccbeca..9a3c315b13e4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6333,7 +6333,8 @@  int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
 
 	r = kvm_skip_emulated_instruction(vcpu);
 
-	if (kvm_hv_hypercall_enabled(vcpu->kvm))
+	if (kvm_hv_hypercall_enabled(vcpu->kvm)
+			&& !kvmi_is_agent_hypercall(vcpu))
 		return kvm_hv_hypercall(vcpu);
 
 	nr = kvm_register_read(vcpu, VCPU_REGS_RAX);
@@ -6371,6 +6372,16 @@  int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
 		ret = kvm_pv_clock_pairing(vcpu, a0, a1);
 		break;
 #endif
+	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:
+		kvmi_hypercall_event(vcpu);
+		ret = 0;
+		break;
 	default:
 		ret = -KVM_ENOSYS;
 		break;