On Tue, Dec 12, 2023, Kirill A. Shutemov wrote:

On Tue, Dec 05, 2023 at 03:45:01AM +0300, Kirill A. Shutemov wrote:

quoted

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 enabled.

Signed-off-by: Kirill A. Shutemov <redacted>
Fixes: c02027b5742b ("x86/kvm: Disable kvmclock on all CPUs on shutdown")
Reviewed-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Wanpeng Li <redacted>

Paolo, Sean, any chance you can get it in through KVM tree while the rest
of kexec patchset is pending? The problem is visible on normal reboot too.

Paolo is going to grab this (possibly for 6.7-rc?).  I'll keep this tagged on my
end in case that doesn't happen "soon".