linux-kernel - Re: [Part2 PATCH v6.1 16/38] crypto: ccp: Add Secure Encrypted Virtualization (SEV) command support

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Date:   Mon, 30 Oct 2017 18:57:08 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Brijesh Singh <brijesh.singh@....com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Gary Hook <gary.hook@....com>,
        Tom Lendacky <thomas.lendacky@....com>,
        linux-crypto@...r.kernel.org, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [Part2 PATCH v6.1 16/38] crypto: ccp: Add Secure Encrypted
 Virtualization (SEV) command support

On Mon, Oct 30, 2017 at 12:49:14PM -0500, Brijesh Singh wrote:
> If the buffer is allocated on the stack then there is no guarantee that

static global is not allocated on the stack.

> I can certainly move the allocation outside, but then it may increase the
> code size in other functions. If its not a big deal then I would prefer to
> keep what we have.

Avoiding repeated k*alloc calls is always a good thing. Actually kmalloc-ing 20
bytes each time sounds like it is not worth the calling overhead to me.

> The function is not used by userspace ioctl, its used by kvm drv when it
> launch/terminates the SEV guest.

Just do that directly in the ioctl instead of having a dumb function.

-- 
Regards/Gruss,
    Boris.

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