From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dave Hansen <dave.hansen-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Subject: Re: [RFC PATCH 03/20] x86/sgx: Track owning enclave in VA EPC pages
Date: Thu, 22 Sep 2022 14:39:53 -0700
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To: Kristen Carlson Accardi <kristen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-sgx-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jarkko Sakkinen <jarkko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Dave Hansen <dave.hansen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>, Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>, x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, "H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
Cc: Sean Christopherson <seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>

On 9/22/22 13:04, Kristen Carlson Accardi wrote:
>> BTW, is there a flag or any other way to tell to what kind of object
>> ->owner points?
> The owner will only be an sgx_encl type if it is a va page, so to tell
> what kind of object owner is, you look at the epc page flags - like
> this:
>         if (epc_page->flags & SGX_EPC_PAGE_ENCLAVE)
>                 encl = ((struct sgx_encl_page *)epc_page->owner)->encl;
>         else if (epc_page->flags & SGX_EPC_PAGE_VERSION_ARRAY)
>                 encl = epc_page->owner;
> ...

I don't know how much refactoring it would take, but it would be nice if
that was a bit more obvious.  Basically, can we get the code that checks
for or sets SGX_EPC_PAGE_VERSION_ARRAY close to the code that assigns or
reads ->owner?