[PATCHv4 05/14] x86/kvm: Do not try to disable kvmclock if it was not enabled

[Kirill A. Shutemov]

On Wed, Dec 13, 2023 at 09:22:34AM -0800, Sean Christopherson wrote:
> On Tue, Dec 12, 2023, Kirill A. Shutemov wrote:
> > On Tue, Dec 05, 2023 at 03:45:01AM +0300, 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 enabled.
> > > 
> > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov at linux.intel.com>
> > > Fixes: c02027b5742b ("x86/kvm: Disable kvmclock on all CPUs on shutdown")
> > > Reviewed-by: Sean Christopherson <seanjc at google.com>
> > > Reviewed-by: Vitaly Kuznetsov <vkuznets at redhat.com>
> > > Cc: Paolo Bonzini <pbonzini at redhat.com>
> > > Cc: Wanpeng Li <wanpengli at tencent.com>
> > 
> > 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".

Sean, any update on this?

-- 
  Kiryl Shutsemau / Kirill A. Shutemov