Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Thu, 19 Aug 2021 10:52:53 +0100
From:   Christoph Hellwig <hch@infradead.org>
To:     Tom Lendacky <thomas.lendacky@amd.com>
Cc:     linux-kernel@vger.kernel.org, x86@kernel.org,
        linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
        iommu@lists.linux-foundation.org, kvm@vger.kernel.org,
        linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org,
        linux-graphics-maintainer@vmware.com,
        amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org,
        Borislav Petkov <bp@alien8.de>,
        Brijesh Singh <brijesh.singh@amd.com>,
        Joerg Roedel <joro@8bytes.org>,
        Andi Kleen <ak@linux.intel.com>,
        Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        Tianyu Lan <Tianyu.Lan@microsoft.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Joerg Roedel <jroedel@suse.de>
Subject: Re: [PATCH v2 03/12] x86/sev: Add an x86 version of prot_guest_has()
Message-ID: <YR4p9TqKTLdN1A96@infradead.org>
References: <cover.1628873970.git.thomas.lendacky@amd.com>
 <7d55bac0cf2e73f53816bce3a3097877ed9663f3.1628873970.git.thomas.lendacky@amd.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <7d55bac0cf2e73f53816bce3a3097877ed9663f3.1628873970.git.thomas.lendacky@amd.com>
Precedence: bulk

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?