On Mon, 2013-12-09 at 15:23 +0100, Paolo Bonzini wrote:
> Il 08/12/2013 12:33, Vadim Rozenfeld ha scritto:
> > Signed-off: Peter Lieven <pl@xxxxxxx>
> > Signed-off: Gleb Natapov <gleb@xxxxxxxxxx>
> > Signed-off: Vadim Rozenfeld <vrozenfe@xxxxxxxxxx>
> >
> > v1 -> v2
> > 1. mark TSC page dirty as suggested by
> > Eric Northup <digitaleric@xxxxxxxxxx> and Gleb
> > 2. disable local irq when calling get_kernel_ns,
> > as it was done by Peter Lieven <pl@xxxxxxxxx>
> > 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,
>
> You need to bump KVM_SAVE_MSRS_BEGIN.
>
> > 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();
>
> Please add a patch that moves these four lines from KVM_GET_CLOCK and
> KVM_SET_CLOCK
>
> local_irq_disable();
> now_ns = get_kernel_ns();
> delta = user_ns.clock - now_ns;
> local_irq_enable();
> kvm->arch.kvmclock_offset = delta;
> kvm_gen_update_masterclock(kvm);
>
> local_irq_disable();
> now_ns = get_kernel_ns();
> user_ns.clock = kvm->arch.kvmclock_offset + now_ns;
> local_irq_enable();
>
> For example u64 kvm_get_clock_ns(struct kvm *) and void
> kvm_set_clock_ns(struct kvm *, u64). You can then use the
> kvm_get_clock_ns function in this patch.
>
OK.
> > + break;
> > + }
> > + case HV_X64_MSR_REFERENCE_TSC: {
> > + u64 gfn;
> > + unsigned long addr;
> > + HV_REFERENCE_TSC_PAGE tsc_ref;
> > + tsc_ref.tsc_sequence = 0;
>
> Please zero it with memset. You're leaking values from the stack to the
> guest.
I can do it, but it is probably not necessary, mostly because guest
allocates one page from nonpaged pool and uses it exclusively for
vTSC purpose only, and host only interested in three values, located at
the beginning of this page.
>
> > + 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();
>
> Another possible user of kvm_get_clock_ns.
>
> The patch should be good with these changes.
Thanks,
Vadim.
>
> Paolo
>
> > + 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;
> > @@ -2605,6 +2641,7 @@ int kvm_dev_ioctl_check_extension(long ext)
> > case KVM_CAP_ASSIGN_DEV_IRQ:
> > case KVM_CAP_PCI_2_3:
> > #endif
> > + case KVM_CAP_HYPERV_TIME:
> > r = 1;
> > break;
> > case KVM_CAP_COALESCED_MMIO:
> > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> > index 902f124..686c1ca 100644
> > --- a/include/uapi/linux/kvm.h
> > +++ b/include/uapi/linux/kvm.h
> > @@ -674,6 +674,7 @@ struct kvm_ppc_smmu_info {
> > #define KVM_CAP_ARM_EL1_32BIT 93
> > #define KVM_CAP_SPAPR_MULTITCE 94
> > #define KVM_CAP_EXT_EMUL_CPUID 95
> > +#define KVM_CAP_HYPERV_TIME 96
> >
> > #ifdef KVM_CAP_IRQ_ROUTING
> >
> >
>
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