Re: [PATCH] x86/sev-es: Invalidate the GHCB after completing VMGEXIT

[Joerg Roedel]

Hi Tom,

On Fri, May 14, 2021 at 02:12:33PM -0500, Tom Lendacky wrote:
>  arch/x86/kernel/sev-shared.c |  1 +
>  arch/x86/kernel/sev.c        | 37 ++++++++++++++++++------------------
>  2 files changed, 20 insertions(+), 18 deletions(-)

Having this change in one patch is okay. No need to split it up.

> +static __always_inline void sev_es_put_ghcb(struct ghcb_state *state)
> +{
> +	struct sev_es_runtime_data *data;
> +	struct ghcb *ghcb;
> +
> +	data = this_cpu_read(runtime_data);
> +	ghcb = &data->ghcb_page;
> +
> +	if (state->ghcb) {
> +		/* Restore GHCB from Backup */
> +		*ghcb = *state->ghcb;
> +		data->backup_ghcb_active = false;
> +		state->ghcb = NULL;
> +	} else {
> +		vc_ghcb_invalidate(ghcb);

A comment would be good to explain why the invalidate here is
necessary.

Regards,

	Joerg