linux-kernel - Re: [PATCH v9 33/43] x86/compressed: Add SEV-SNP feature detection/setup

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Date:   Sun, 6 Feb 2022 17:41:26 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Brijesh Singh <brijesh.singh@....com>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        linux-efi@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        linux-coco@...ts.linux.dev, linux-mm@...ck.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Joerg Roedel <jroedel@...e.de>,
        Tom Lendacky <thomas.lendacky@....com>,
        "H. Peter Anvin" <hpa@...or.com>, Ard Biesheuvel <ardb@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Jim Mattson <jmattson@...gle.com>,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Sergio Lopez <slp@...hat.com>, Peter Gonda <pgonda@...gle.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        David Rientjes <rientjes@...gle.com>,
        Dov Murik <dovmurik@...ux.ibm.com>,
        Tobin Feldman-Fitzthum <tobin@....com>,
        Michael Roth <michael.roth@....com>,
        Vlastimil Babka <vbabka@...e.cz>,
        "Kirill A . Shutemov" <kirill@...temov.name>,
        Andi Kleen <ak@...ux.intel.com>,
        "Dr . David Alan Gilbert" <dgilbert@...hat.com>,
        brijesh.ksingh@...il.com, tony.luck@...el.com, marcorr@...gle.com,
        sathyanarayanan.kuppuswamy@...ux.intel.com
Subject: Re: [PATCH v9 33/43] x86/compressed: Add SEV-SNP feature
 detection/setup

On Fri, Jan 28, 2022 at 11:17:54AM -0600, Brijesh Singh wrote:
> +static struct cc_setup_data *get_cc_setup_data(struct boot_params *bp)
> +{
> +	struct setup_data *hdr = (struct setup_data *)bp->hdr.setup_data;
> +
> +	while (hdr) {
> +		if (hdr->type == SETUP_CC_BLOB)
> +			return (struct cc_setup_data *)hdr;
> +		hdr = (struct setup_data *)hdr->next;
> +	}
> +
> +	return NULL;
> +}

Merge that function into its only caller.

...

> +static struct cc_blob_sev_info *snp_find_cc_blob(struct boot_params *bp)

static function, no need for the "snp_" prefix. Please audit all your
patches for that and remove that prefix from all static functions.

> +{
> +	struct cc_blob_sev_info *cc_info;
> +
> +	cc_info = snp_find_cc_blob_efi(bp);
> +	if (cc_info)
> +		goto found_cc_info;
> +
> +	cc_info = snp_find_cc_blob_setup_data(bp);
> +	if (!cc_info)
> +		return NULL;
> +
> +found_cc_info:
> +	if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC)
> +		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
> +
> +	return cc_info;
> +}
> +
> +bool snp_init(struct boot_params *bp)
> +{
> +	struct cc_blob_sev_info *cc_info;
> +
> +	if (!bp)
> +		return false;
> +
> +	cc_info = snp_find_cc_blob(bp);
> +	if (!cc_info)
> +		return false;
> +
> +	/*
> +	 * Pass run-time kernel a pointer to CC info via boot_params so EFI
> +	 * config table doesn't need to be searched again during early startup
> +	 * phase.
> +	 */
> +	bp->cc_blob_address = (u32)(unsigned long)cc_info;
> +
> +	/*
> +	 * Indicate SEV-SNP based on presence of SEV-SNP-specific CC blob.
> +	 * Subsequent checks will verify SEV-SNP CPUID/MSR bits.
> +	 */

Put that comment over the function name.

Thx.

-- 
Regards/Gruss,
    Boris.

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