Re: [PATCH v11 11/20] x86/virt/tdx: Fill out TDMRs to cover all TDX memory regions

[Dave Hansen]

On 6/4/23 07:27, Kai Huang wrote:
> +	/*
> +	 * Loop over TDX memory regions and fill out TDMRs to cover them.
> +	 * To keep it simple, always try to use one TDMR to cover one
> +	 * memory region.
> +	 *
> +	 * In practice TDX1.0 supports 64 TDMRs, which is big enough to
> +	 * cover all memory regions in reality if the admin doesn't use
> +	 * 'memmap' to create a bunch of discrete memory regions.  When
> +	 * there's a real problem, enhancement can be done to merge TDMRs
> +	 * to reduce the final number of TDMRs.
> +	 */

Rather than focus in on one specific command-line parameter, let's just say:

	In practice TDX supports at least 64 TDMRs.  A 2-socket system
	typically only consumes <NUMBER> of those.  This code is dumb
	and simple and may use more TMDRs than is strictly required.

Let's also put a pr_warn() in here if we exceed, say 1/2 or maybe 3/4 of
the 64.  We'll hopefully start to get reports somewhat in advance if
systems get close to the limit.