Re: [PATCH 11/12] x86/sev: Handle CLFLUSH MMIO events

Hi Sean,

On Fri, Jul 30, 2021 at 10:42:30PM +0000, Sean Christopherson wrote:

On Wed, Jul 21, 2021, Joerg Roedel wrote:
This wording can be misread as "the hypervisor is responsible for _all_ cache
management".  Maybe just:

		/*
		 * Ignore CLFLUSHes - the hyperivsor is responsible for cache
		 * management of emulated MMIO.
		 */

Right, will update the comment, thanks.

Side topic, out of curisoity, what's mapping/accessing emulated MMIO as non-UC?

The CLFLUSHes happen when the kexec'ed kernel maps the VGA framebuffer
as unencrypted. Initially it is mapped encrypted and before re-mapping
the kernel flushes the range from the caches.

I have not investigated why this doesn't happen on the first boot,
though.

Regards,

	Joerg