From: Adalbert Lazar <alazar@xxxxxxxxxxxxxxx>
Inform the guest introspection tool that an MSR is going to be changed.
The kvmi_msr_event() function will check a bitmap of MSR-s of interest
(configured via a KVMI_CONTROL_EVENTS(KVMI_MSR_CONTROL) request) and, if
the new value differs from the previous one, it will generate a
notification. The introspection tool can respond by allowing the guest
to continue with normal execution or by discarding the change.
This is meant to prevent malicious changes to MSR-s such as
MSR_IA32_SYSENTER_EIP.
Signed-off-by: Mihai Donțu <mdontu@xxxxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 284bb4c740fa..271028ccbeca 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1111,6 +1111,9 @@ EXPORT_SYMBOL_GPL(kvm_enable_efer_bits);
*/
int kvm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
{
+ if (!kvmi_msr_event(vcpu, msr))
+ return 1;
+
switch (msr->index) {
case MSR_FS_BASE:
case MSR_GS_BASE:
