Re: [PATCH v5 06/14] x86/ioremap: Support hypervisor specified range to map as encrypted

[Borislav Petkov]

On Thu, Mar 09, 2023 at 03:36:45PM +0100, Jörg Rödel wrote:
> Yes, that is right. The key is mainly for the NMI entry path which can
> be performance relevant in some situations. For SEV-ES some special
> handling is needed there to re-enable NMIs and adjust the #VC stack in
> case it was raised on the VC-handlers entry path.

So the performance argument is meh. That key will be replaced by

	if (cc_vendor == CC_VENDOR_AMD &&
	    cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)

which is something like 4 insns or so. Tops.

Haven't looked yet but it should be cheap.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette