kvm/x86: Hyper-V kvm exit
A new vcpu exit is introduced to notify the userspace of the
changes in Hyper-V SynIC configuration triggered by guest writing to the
corresponding MSRs.
Changes v4:
* exit into userspace only if guest writes into SynIC MSR's
Changes v3:
* added KVM_EXIT_HYPERV types and structs notes into docs
Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: qemu-devel@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 83a3c0c..41869a9 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -130,6 +130,20 @@
srcu_read_unlock(&kvm->irq_srcu, idx);
}
+static void synic_exit(struct kvm_vcpu_hv_synic *synic, u32 msr)
+{
+ struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
+ struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv;
+
+ hv_vcpu->exit.type = KVM_EXIT_HYPERV_SYNIC;
+ hv_vcpu->exit.u.synic.msr = msr;
+ hv_vcpu->exit.u.synic.control = synic->control;
+ hv_vcpu->exit.u.synic.evt_page = synic->evt_page;
+ hv_vcpu->exit.u.synic.msg_page = synic->msg_page;
+
+ kvm_make_request(KVM_REQ_HV_EXIT, vcpu);
+}
+
static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
u32 msr, u64 data, bool host)
{
@@ -145,6 +159,8 @@
switch (msr) {
case HV_X64_MSR_SCONTROL:
synic->control = data;
+ if (!host)
+ synic_exit(synic, msr);
break;
case HV_X64_MSR_SVERSION:
if (!host) {
@@ -161,6 +177,8 @@
break;
}
synic->evt_page = data;
+ if (!host)
+ synic_exit(synic, msr);
break;
case HV_X64_MSR_SIMP:
if (data & HV_SYNIC_SIMP_ENABLE)
@@ -170,6 +188,8 @@
break;
}
synic->msg_page = data;
+ if (!host)
+ synic_exit(synic, msr);
break;
case HV_X64_MSR_EOM: {
int i;