linux-kernel - Re: [PATCH V4] virt: sev: Prevent IV reuse in SNP guest driver

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Date:   Tue, 15 Nov 2022 22:36:17 +0100
From:   Borislav Petkov <bp@...e.de>
To:     Peter Gonda <pgonda@...gle.com>
Cc:     thomas.lendacky@....com, Dionna Glaze <dionnaglaze@...gle.com>,
        Michael Roth <michael.roth@....com>,
        Haowen Bai <baihaowen@...zu.com>,
        Yang Yingliang <yangyingliang@...wei.com>,
        Marc Orr <marcorr@...gle.com>,
        David Rientjes <rientjes@...gle.com>,
        Ashish Kalra <Ashish.Kalra@....com>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH V4] virt: sev: Prevent IV reuse in SNP guest driver

On Mon, Nov 14, 2022 at 02:11:48PM -0700, Peter Gonda wrote:
> Thanks for detailed review. Working on cleaning up the text for a V5.

Yeah, and I have some questions in my reply which you haven't
addressed...

> > > @@ -676,7 +712,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
> > >       if (!snp_dev->response)
> > >               goto e_free_request;
> > >
> > > -     snp_dev->certs_data = alloc_shared_pages(dev, SEV_FW_BLOB_MAX_SIZE);
> > > +     snp_dev->certs_data = alloc_shared_pages(dev, sizeof(*snp_dev->certs_data));
> >
> > What's that change for?
> >
> > I went searching for that ->certs_data only ot realize that it is an
> > array of size of SEV_FW_BLOB_MAX_SIZE elems.
> 
> Do you want this change reverted? I liked the extra readability of the
> sizeof(*snp_dev->certs_data) but its unnecessary for this change.

Really?

I think using a define which is a SIZE define is better. Especially if
you look at

	sizeof(*snp_dev->certs_data)

and wonder what type ->certs_data is.

And it's not like it'll go out of sync since it is an array of size,
well, SEV_FW_BLOB_MAX_SIZE.

:-)

Thx.

-- 
Regards/Gruss,
    Boris.

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