Re: [PATCH v4] KVM: VMX: Cap VMX preemption timer to work around Intel erratum

[Sean Christopherson <seanjc@google.com>]

On Wed, Jul 22, 2026, Jim Mattson wrote:
> @@ -8735,7 +8758,8 @@ __init int vmx_hardware_setup(void)
>  		 * value.  Don't use the timer if it might cause spurious exits
>  		 * at a rate faster than 0.1 Hz (of uninterrupted guest time).
>  		 */
> -		if (use_timer_freq > 0xffffffffu / 10)
> +		if (!preemption_timer_limit ||
> +		    use_timer_freq > (preemption_timer_limit - 1) / 10)

There's still a 64-bit DIV in here, I'm guessing it's this one.

   ERROR: modpost: "__udivdi3" [arch/x86/kvm/kvm-intel.ko] undefined!

I'm not interested in playing whack-a-mole, please base v5 on my patch to make
this code 64-bit-only.  It's small enough that I'm comfortable sending it to LTS
kernels if we want to tag this for stable@.

>  			enable_preemption_timer = false;
>  	}
>  
> -- 
> 2.55.0.229.g6434b31f56-goog
>