# Re: \[PATCH v2 03/12\] x86/sev: Add an x86 version of prot\_guest\_has()

- From: Christoph Hellwig \<hch@infradead.org\>
- Date: 2021-08-19 09:54:21 
- List: linux-efi
- Page: https://ratatoskr.run/linux-efi/2021/08/212778
- Thread: https://ratatoskr.run/linuxppc-dev/2021/08/212359/t.md

```text
On Fri, Aug 13, 2021 at 11:59:22AM -0500, Tom Lendacky wrote:
> While the name suggests this is intended mainly for guests, it will
> also be used for host memory encryption checks in place of sme_active().

Which suggest that the name is not good to start with.  Maybe protected
hardware, system or platform might be a better choice?

> +static inline bool prot_guest_has(unsigned int attr)
> +{
> +#ifdef CONFIG_AMD_MEM_ENCRYPT
> +	if (sme_me_mask)
> +		return amd_prot_guest_has(attr);
> +#endif
> +
> +	return false;
> +}

Shouldn't this be entirely out of line?

> +/* 0x800 - 0x8ff reserved for AMD */
> +#define PATTR_SME			0x800
> +#define PATTR_SEV			0x801
> +#define PATTR_SEV_ES			0x802

Why do we need reservations for a purely in-kernel namespace?

And why are you overoading a brand new generic API with weird details
of a specific implementation like this?
```