linux-kernel - Re: [PATCH v8 1/2] x86/mm: add .bss..decrypted section to hold shared variables

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Message-ID: <20180914144518.GB29898@zn.tnic>
Date:   Fri, 14 Sep 2018 16:45:18 +0200
From:   Borislav Petkov <bp@...e.de>
To:     Brijesh Singh <brijesh.singh@....com>
Cc:     Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Tom Lendacky <thomas.lendacky@....com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Radim Krčmář <rkrcmar@...hat.com>
Subject: Re: [PATCH v8 1/2] x86/mm: add .bss..decrypted section to hold
 shared variables

On Fri, Sep 14, 2018 at 09:27:09AM -0500, Brijesh Singh wrote:
> The above code will never get executed for the SEV case.
> 
> See if (!sme_active()) check in the start of function.
> 
> If we decide to go on this patch, then we have to do something like
> this:
> 
> sme_encrypt_kernel(...)
> {
> 	if (!mem_encrypt_active())
> 		return;
> 
> 	if (sev_active())
> 		goto out;
> 
> 	/* Do kernel and initrd in-place encrypts for SME only case */
> 	.....
> 	.....
> 
> out:
> 	/* Clear the C-bit from .bss..decrypted section */
> 	...
> 	...

Or above do:

	if (sev_active()) {
		sev_map_bss_decrypted();
                return;
	}

which is a separate function you call.

So that you not have a label at the end of the function. Whatever tglx
prefers.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--