Re: [PATCH v2 12/12] x86/traps: Fix up invalid PASID

[Peter Zijlstra]

On Fri, Jun 12, 2020 at 05:41:33PM -0700, Fenghua Yu wrote:
> @@ -447,6 +458,18 @@ dotraplinkage void do_general_protection(struct pt_regs *regs, long error_code)
>  	int ret;
>  
>  	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
> +
> +	/*
> +	 * Perform the check for a user mode PASID exception before enable
> +	 * interrupts. Doing this here ensures that the PASID MSR can be simply
> +	 * accessed because the contents are known to be still associated
> +	 * with the current process.
> +	 */
> +	if (user_mode(regs) && fixup_pasid_exception()) {
> +		cond_local_irq_enable(regs);
> +		return;

OK, so we're done with the exception, lets enable interrupts?

> +	}