Re: [PATCH v2 3/4] x86/mm: Flush global TLB when switching to trampoline page-table

[Dave Hansen]

On 9/29/21 7:55 AM, Joerg Roedel wrote:
> +	/*
> +	 * Flush global TLB entries to catch any bugs where code running on the
> +	 * trampoline_pgd uses memory not mapped into the trampoline page-table.
> +	 */
> +	__flush_tlb_all();
> +}

This comment took me a minute to parse.  How about a bit more info, like:

	/*
	 * The CR3 writes above may not flush global TLB entries.
	 * Stale, global entries from previous sets of page tables may
	 * still be present.  Flush those stale entries.
	 *
	 * This ensures that memory accessed while running with
	 * trampoline_pgd is *actually* mapped into trampoline_pgd.
	 */