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    SubjectRe: [PATCH 04/13] x86/kvm: Do not try to disable kvmclock if it was not enabled
    On Tue, Oct 10, 2023 at 06:53:27AM -0700, Kuppuswamy Sathyanarayanan wrote:
    >
    >
    > On 10/5/2023 6:13 AM, Kirill A. Shutemov wrote:
    > > kvm_guest_cpu_offline() tries to disable kvmclock regardless if it is
    > > present in the VM. It leads to write to a MSR that doesn't exist on some
    > > configurations, namely in TDX guest:
    > >
    > > unchecked MSR access error: WRMSR to 0x12 (tried to write 0x0000000000000000)
    > > at rIP: 0xffffffff8110687c (kvmclock_disable+0x1c/0x30)
    > >
    > > kvmclock enabling is gated by CLOCKSOURCE and CLOCKSOURCE2 KVM paravirt
    > > features.
    > >
    > > Do not disable kvmclock if it was not enumerated or disabled by user
    > > from kernel command line.
    >
    > For the above warning, check for CLOCKSOURCE and CLOCKSOURCE2
    > feature is sufficient, right? Do we need to include user/command-line
    > disable check here?

    The command line disables kvmclock, even if it is enumerated, so disabling
    it is not needed.

    Anyway, I reworked the patch already based on Sean's feedback. No need in
    taking parameter into account directly now.

    --
    Kiryl Shutsemau / Kirill A. Shutemov

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