add support for Hyper-V reference time counter
Signed-off: Peter Lieven <pl@kamp.de>
Signed-off: Gleb Natapov
Signed-off: Vadim Rozenfeld <vrozenfe@redhat.com>
After some consideration I decided to submit only Hyper-V reference
counters support this time. I will submit iTSC support as a separate
patch as soon as it is ready.
v1 -> v2
1. mark TSC page dirty as suggested by
Eric Northup <digitaleric@google.com> and Gleb
2. disable local irq when calling get_kernel_ns,
as it was done by Peter Lieven <pl@amp.de>
3. move check for TSC page enable from second patch
to this one.
v3 -> v4
Get rid of ref counter offset.
v4 -> v5
replace __copy_to_user with kvm_write_guest
when updateing iTSC page.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0fbdced..0b3fd80 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -839,11 +839,12 @@
* kvm-specific. Those are put in the beginning of the list.
*/
-#define KVM_SAVE_MSRS_BEGIN 10
+#define KVM_SAVE_MSRS_BEGIN 12
static u32 msrs_to_save[] = {
MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW,
HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
+ HV_X64_MSR_TIME_REF_COUNT, HV_X64_MSR_REFERENCE_TSC,
HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
MSR_KVM_PV_EOI_EN,
MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
@@ -1788,6 +1789,8 @@
switch (msr) {
case HV_X64_MSR_GUEST_OS_ID:
case HV_X64_MSR_HYPERCALL:
+ case HV_X64_MSR_REFERENCE_TSC:
+ case HV_X64_MSR_TIME_REF_COUNT:
r = true;
break;
}
@@ -1829,6 +1832,20 @@
kvm->arch.hv_hypercall = data;
break;
}
+ case HV_X64_MSR_REFERENCE_TSC: {
+ u64 gfn;
+ HV_REFERENCE_TSC_PAGE tsc_ref;
+ memset(&tsc_ref, 0, sizeof(tsc_ref));
+ kvm->arch.hv_tsc_page = data;
+ if (!(data & HV_X64_MSR_TSC_REFERENCE_ENABLE))
+ break;
+ gfn = data >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT;
+ if (kvm_write_guest(kvm, data,
+ &tsc_ref, sizeof(tsc_ref)))
+ return 1;
+ mark_page_dirty(kvm, gfn);
+ break;
+ }
default:
vcpu_unimpl(vcpu, "HYPER-V unimplemented wrmsr: 0x%x "
"data 0x%llx\n", msr, data);
@@ -2253,6 +2270,14 @@
case HV_X64_MSR_HYPERCALL:
data = kvm->arch.hv_hypercall;
break;
+ case HV_X64_MSR_TIME_REF_COUNT: {
+ data =
+ div_u64(get_kernel_ns() + kvm->arch.kvmclock_offset, 100);
+ break;
+ }
+ case HV_X64_MSR_REFERENCE_TSC:
+ data = kvm->arch.hv_tsc_page;
+ break;
default:
vcpu_unimpl(vcpu, "Hyper-V unhandled rdmsr: 0x%x\n", msr);
return 1;
@@ -2566,6 +2591,7 @@
#ifdef CONFIG_KVM_DEVICE_ASSIGNMENT
case KVM_CAP_ASSIGN_DEV_IRQ:
case KVM_CAP_PCI_2_3:
+ case KVM_CAP_HYPERV_TIME:
#endif
r = 1;
break;