Re: [PATCH v3 0/2] KVM: x86: hyper-v: Fix TSC page update after KVM_SET_CLOCK(0) call

[Paolo Bonzini]

On 31/03/21 14:41, Vitaly Kuznetsov wrote:
> Changes since v2:
> - Fix the issue by using master_kernel_ns/get_kvmclock_base_ns() instead of
>   get_kvmclock_ns() when handling KVM_SET_CLOCK.
> - Rebase on Paolo's "KVM: x86: fix lockdep splat due to Xen runstate
>   update" series and use spin_lock_irq()/spin_unlock_irq() [Paolo]
>
> Original description:
>
> I discovered that after KVM_SET_CLOCK(0) TSC page value in the guest can
> go through the roof and apparently we have a signedness issue when the
> update is performed. Fix the issue and add a selftest.
>
> Vitaly Kuznetsov (2):
>    KVM: x86: Prevent 'hv_clock->system_time' from going negative in
>      kvm_guest_time_update()
>    selftests: kvm: Check that TSC page value is small after
>      KVM_SET_CLOCK(0)
>
>   arch/x86/kvm/x86.c                            | 19 +++++++++++++++++--
>   .../selftests/kvm/x86_64/hyperv_clock.c       | 13 +++++++++++--
>   2 files changed, 28 insertions(+), 4 deletions(-)

Queued, thanks.

Paolo