linux-kernel - Re: Rename restrictedmem => guardedmem? (was: Re: [PATCH v10 0/9] KVM: mm: fd-based approach for supporting KVM)

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Message-ID: <diqzv8huxwl0.fsf@ackerleytng-cloudtop.c.googlers.com>
Date:   Mon, 17 Apr 2023 17:11:39 +0000
From:   Ackerley Tng <ackerleytng@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     david@...hat.com, chao.p.peng@...ux.intel.com, pbonzini@...hat.com,
        vkuznets@...hat.com, jmattson@...gle.com, joro@...tes.org,
        mail@...iej.szmigiero.name, vbabka@...e.cz, vannapurve@...gle.com,
        yu.c.zhang@...ux.intel.com, kirill.shutemov@...ux.intel.com,
        dhildenb@...hat.com, qperret@...gle.com, tabba@...gle.com,
        michael.roth@....com, wei.w.wang@...el.com, rppt@...nel.org,
        liam.merwick@...cle.com, isaku.yamahata@...il.com,
        jarkko@...nel.org, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: Rename restrictedmem => guardedmem? (was: Re: [PATCH v10 0/9]
 KVM: mm: fd-based approach for supporting KVM)

Sean Christopherson <seanjc@...gle.com> writes:

> On Mon, Apr 17, 2023, David Hildenbrand wrote:
>> On 17.04.23 17:40, Sean Christopherson wrote:
>> > I want to start referring to the code/patches by its  
>> syscall/implementation name
>> > instead of "UPM", as "UPM" is (a) very KVM centric, (b) refers to the  
>> broader effort
>> > and not just the non-KVM code, and (c) will likely be confusing for  
>> future reviewers
>> > since there's nothing in the code that mentions "UPM" in any way.
>> >
>> > But typing out restrictedmem is quite tedious, and git grep shows  
>> that "rmem" is
>> > already used to refer to "reserved memory".
>> >
>> > Renaming the syscall to "guardedmem"...

>> restrictedmem, guardedmem, ... all fairly "suboptimal" if you'd ask  
>> me ...

> I'm definitely open to other suggestions, but I suspect it's going to be  
> difficult
> to be more precise than something like "guarded".

> E.g. we discussed "unmappable" at one point, but the memory can still be  
> mapped,
> just not via mmap().  And it's not just about mappings, e.g. read() and  
> its many
> variants are all disallowed too, despite the kernel direct map still  
> being live
> (modulo SNP requirements).

I'm for renaming the concept because restrictedmem is quite a
mouthful. :)

How about "concealedmem" or "obscuredmem" to highlight the idea of this
memory being hidden/unreadable/unmappable from userspace?

Guarded is better than restricted but doesn't really highlight how/in
what way it is being guarded.