Am 11.12.2013 19:53, schrieb Marcelo Tosatti:
> On Sun, Dec 08, 2013 at 10:33:38PM +1100, Vadim Rozenfeld wrote:
>> Signed-off: Peter Lieven <p...@dlh.net>
>> Signed-off: Gleb Natapov <g...@redhat.com>
>> Signed-off: Vadim Rozenfeld <vroze...@redhat.com>
>>
>> v1 -> v2
>> 1. mark TSC page dirty as suggested by
>> Eric Northup <digitale...@google.com> and Gleb
>> 2. disable local irq when calling get_kernel_ns,
>> as it was done by Peter Lieven <p...@dlhnet.de>
>> 3. move check for TSC page enable from second patch
>> to this one.
>>
>> ---
>> arch/x86/include/asm/kvm_host.h | 2 ++
>> arch/x86/include/uapi/asm/hyperv.h | 13 +++++++++++++
>> arch/x86/kvm/x86.c | 39
>> +++++++++++++++++++++++++++++++++++++-
>> include/uapi/linux/kvm.h | 1 +
>> 4 files changed, 54 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/include/asm/kvm_host.h
>> b/arch/x86/include/asm/kvm_host.h
>> index ae5d783..2fd0753 100644
>> --- a/arch/x86/include/asm/kvm_host.h
>> +++ b/arch/x86/include/asm/kvm_host.h
>> @@ -605,6 +605,8 @@ 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 b8f1c01..462efe7 100644
>> --- a/arch/x86/include/uapi/asm/hyperv.h
>> +++ b/arch/x86/include/uapi/asm/hyperv.h
>> @@ -28,6 +28,9 @@
>> /* Partition Reference Counter (HV_X64_MSR_TIME_REF_COUNT) available*/
>> #define HV_X64_MSR_TIME_REF_COUNT_AVAILABLE (1 << 1)
>>
>> +/* A partition's reference time stamp counter (TSC) page */
>> +#define HV_X64_MSR_REFERENCE_TSC 0x40000021
>> +
>> /*
>> * There is a single feature flag that signifies the presence of the MSR
>> * that can be used to retrieve both the local APIC Timer frequency as
>> @@ -198,6 +201,9 @@
>> #define HV_X64_MSR_APIC_ASSIST_PAGE_ADDRESS_MASK \
>> (~((1ull << HV_X64_MSR_APIC_ASSIST_PAGE_ADDRESS_SHIFT) - 1))
>>
>> +#define HV_X64_MSR_TSC_REFERENCE_ENABLE 0x00000001
>> +#define HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT 12
>> +
>> #define HV_PROCESSOR_POWER_STATE_C0 0
>> #define HV_PROCESSOR_POWER_STATE_C1 1
>> #define HV_PROCESSOR_POWER_STATE_C2 2
>> @@ -210,4 +216,11 @@
>> #define HV_STATUS_INVALID_ALIGNMENT 4
>> #define HV_STATUS_INSUFFICIENT_BUFFERS 19
>>
>> +typedef struct _HV_REFERENCE_TSC_PAGE {
>> + __u32 tsc_sequence;
>> + __u32 res1;
>> + __u64 tsc_scale;
>> + __s64 tsc_offset;
>> +} HV_REFERENCE_TSC_PAGE, *PHV_REFERENCE_TSC_PAGE;
>> +
>> #endif
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index 21ef1ba..5e4e495a 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -840,7 +840,7 @@ 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,
>> @@ -1826,6 +1826,8 @@ 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;
>> }
>> @@ -1865,6 +1867,29 @@ 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;
>> + local_irq_disable();
>> + kvm->arch.hv_ref_count = get_kernel_ns() +
>> kvm->arch.kvmclock_offset;
>> + local_irq_enable();
>
> Where does the docs say that HV_X64_MSR_HYPERCALL is the where the clock
> starts counting?
>
> No need to store kvmclock_offset in hv_ref_count? (moreover
> the name is weird, better name would be "hv_ref_start_time".
>
>> + break;
>> + }
>> + case HV_X64_MSR_REFERENCE_TSC: {
>> + u64 gfn;
>> + unsigned long addr;
>> + HV_REFERENCE_TSC_PAGE tsc_ref;
>> + tsc_ref.tsc_sequence = 0;
>> + if (!(data & HV_X64_MSR_TSC_REFERENCE_ENABLE)) {
>> + kvm->arch.hv_tsc_page = data;
>> + break;
>> + }
>> + gfn = data >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT;
>> + addr = gfn_to_hva(kvm, data >>
>> + HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT);
>> + if (kvm_is_error_hva(addr))
>> + return 1;
>> + if (__copy_to_user((void __user *)addr, &tsc_ref,
>> sizeof(tsc_ref)))
>> + return 1;
>> + mark_page_dirty(kvm, gfn);
>> + kvm->arch.hv_tsc_page = data;
>> break;
>> }
>> default:
>> @@ -2291,6 +2316,17 @@ 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: {
>> + u64 now_ns;
>> + local_irq_disable();
>> + now_ns = get_kernel_ns() + kvm->arch.kvmclock_offset;
>> + data = div_u64(now_ns - kvm->arch.hv_ref_count, 100);
>> + local_irq_enable();
>
> No need for irq disable/enable pairs.
KVM_GET_CLOCK / KVM_SET_CLOCK do the irq disable/enable pairs. What is right?
Peter
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