[RFC PATCH 1/2] Hyper-H reference counter

Vadim Rozenfeld
2013-05-13T11:45:40Z

Signed-off: Peter Lieven <pl@dlh.net>
Signed-off: Gleb Natapov <gleb@redhat.com>
Signed-off: Vadim Rozenfeld <vrozenfe@redhat.com>

The following patch allows to activate Hyper-V
reference time counter
---
arch/x86/include/asm/kvm_host.h | 2 ++
arch/x86/include/uapi/asm/hyperv.h | 3 +++
arch/x86/kvm/x86.c | 25 ++++++++++++++++++++++++-
3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3741c65..f0fee35 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -575,6 +575,8 @@ struct kvm_arch {
/* fields used by HYPER-V emulation */
u64 hv_guest_os_id;
u64 hv_hypercall;
+ u64 hv_ref_count;
+ u64 hv_tsc_page;

#ifdef CONFIG_KVM_MMU_AUDIT
int audit_point;
diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h
index b80420b..9711819 100644
--- a/arch/x86/include/uapi/asm/hyperv.h
+++ b/arch/x86/include/uapi/asm/hyperv.h
@@ -136,6 +136,9 @@
/* MSR used to read the per-partition time reference counter */
#define HV_X64_MSR_TIME_REF_COUNT 0x40000020

+/* A partition's reference time stamp counter (TSC) page */
+#define HV_X64_MSR_REFERENCE_TSC 0x40000021
+
/* Define the virtual APIC registers */
#define HV_X64_MSR_EOI 0x40000070
#define HV_X64_MSR_ICR 0x40000071
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 094b5d9..1a4036d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -843,7 +843,7 @@ EXPORT_SYMBOL_GPL(kvm_rdpmc);
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_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,HV_X64_MSR_TIME_REF_COUNT,
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,
@@ -1764,6 +1764,8 @@ static bool kvm_hv_msr_partition_wide(u32 msr)
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;
}
@@ -1803,6 +1805,21 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data)
if (__copy_to_user((void __user *)addr, instructions, 4))
return 1;
kvm->arch.hv_hypercall = data;
+ kvm->arch.hv_ref_count = get_kernel_ns();
+ break;
+ }
+ case HV_X64_MSR_REFERENCE_TSC: {
+ u64 gfn;
+ unsigned long addr;
+ u32 tsc_ref;
+ gfn = data >> HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_SHIFT;
+ addr = gfn_to_hva(kvm, gfn);
+ if (kvm_is_error_hva(addr))
+ return 1;
+ tsc_ref = 0;
+ if(__copy_to_user((void __user *)addr, &tsc_ref, sizeof(tsc_ref)))
+ return 1;
+ kvm->arch.hv_tsc_page = data;
break;
}
default:
@@ -2229,6 +2246,12 @@ static int get_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
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.hv_ref_count,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;
--
1.8.1.2