KVM: X86: Implement call-back to propagate virtual_tsc_khz

This patch implements a call-back into the architecture code
to allow the propagation of changes to the virtual tsc_khz
of the vcpu.
On SVM it updates the tsc_ratio variable, on VMX it does
nothing.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 3dfefe3bcd05..e19c7a5473d5 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1161,6 +1161,16 @@ static u64 guest_read_tsc(void)
 }
 
 /*
+ * Empty call-back. Needs to be implemented when VMX enables the SET_TSC_KHZ
+ * ioctl. In this case the call-back should update internal vmx state to make
+ * the changes effective.
+ */
+static void vmx_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz)
+{
+        /* Nothing to do here */
+}
+
+/*
  * writes 'offset' into guest's timestamp counter offset register
  */
 static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
@@ -4497,6 +4507,7 @@ static struct kvm_x86_ops vmx_x86_ops = {
 
         .has_wbinvd_exit = cpu_has_vmx_wbinvd_exit,
 
+        .set_tsc_khz = vmx_set_tsc_khz,
         .write_tsc_offset = vmx_write_tsc_offset,
         .adjust_tsc_offset = vmx_adjust_tsc_offset,