From: Mihai Dontu <mdontu@xxxxxxxxxxxxxxx>
Code residing inside the introspected guest can call the introspection
tool to report certain details about its operation. For example, a
classic antimalware remediation tool can report what it has found during
a scan.
The VMCALL convention is the one used on Xen (DOMCTL + subop). This code
is largely untested. Its purpose is only to show how guest code
communicates with the introspection tool.
Signed-off-by: Mihai Dontu <mdontu@xxxxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 15 +++++++++++++++
include/uapi/linux/kvm_para.h | 4 ++++
2 files changed, 19 insertions(+)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9465856a9e37..cafe878ba148 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6302,6 +6302,21 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
ret = kvm_pv_clock_pairing(vcpu, a0, a1);
break;
#endif
+ case KVM_HC_XEN_HVM_OP:{
+ unsigned long subop;
+
+ if (op_64_bit) {
+ subop = kvm_register_read(vcpu, VCPU_REGS_RDI);
+ subop &= 0xFFFFFFFF;
+ } else
+ subop = a0;
+
+ if (subop == KVM_HC_XEN_HVM_OP_GUEST_REQUEST_VM_EVENT)
+ kvmi_vmcall_event(vcpu);
+
+ ret = kvm_register_read(vcpu, VCPU_REGS_RAX);
+ break;
+ }
default:
ret = -KVM_ENOSYS;
break;
diff --git a/include/uapi/linux/kvm_para.h b/include/uapi/linux/kvm_para.h
index fed506aeff62..297b75435831 100644
--- a/include/uapi/linux/kvm_para.h
+++ b/include/uapi/linux/kvm_para.h
@@ -25,6 +25,10 @@
#define KVM_HC_MIPS_EXIT_VM 7
#define KVM_HC_MIPS_CONSOLE_OUTPUT 8
#define KVM_HC_CLOCK_PAIRING 9
+#define KVM_HC_XEN_HVM_OP 34
+/* Matches Xen's __HYPERVISOR_hvm_op */
+
+#define KVM_HC_XEN_HVM_OP_GUEST_REQUEST_VM_EVENT 24
/*
* hypercalls use architecture specific
--
2.12.2
