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Date:   Mon, 24 Jul 2023 13:16:26 -0700
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Subject: Re: [RFC PATCH v11 00/29]  KVM: guest_memfd() and per-page attributes
From:   Sean Christopherson <seanjc@google.com>
To:     Sean Christopherson <seanjc@google.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>, Marc Zyngier <maz@kernel.org>,
        Oliver Upton <oliver.upton@linux.dev>,
        Huacai Chen <chenhuacai@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Anup Patel <anup@brainfault.org>,
        Sean Christopherson <seanjc@google.com>, kvm@vger.kernel.org,
        kvmarm@lists.linux.dev, kvm-riscv@lists.infradead.org,
        linux-kernel@vger.kernel.org,
        Chao Peng <chao.p.peng@linux.intel.com>,
        Fuad Tabba <tabba@google.com>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Yu Zhang <yu.c.zhang@linux.intel.com>,
        Vishal Annapurve <vannapurve@google.com>,
        Ackerley Tng <ackerleytng@google.com>,
        Maciej Szmigiero <mail@maciej.szmigiero.name>,
        Vlastimil Babka <vbabka@suse.cz>,
        David Hildenbrand <david@redhat.com>,
        Quentin Perret <qperret@google.com>,
        Michael Roth <michael.roth@amd.com>,
        Wang <wei.w.wang@intel.com>,
        Liam Merwick <liam.merwick@oracle.com>,
        Isaku Yamahata <isaku.yamahata@gmail.com>,
        Kirill Shutemov <kirill.shutemov@linux.intel.com>
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Dropped non-KVM folks from Cc: so as not to bother them too much.

On Tue, Jul 18, 2023, Sean Christopherson wrote:
> This is the next iteration of implementing fd-based (instead of vma-based)
> memory for KVM guests.  If you want the full background of why we are doing
> this, please go read the v10 cover letter[1].
> 
> The biggest change from v10 is to implement the backing storage in KVM
> itself, and expose it via a KVM ioctl() instead of a "generic" sycall.
> See link[2] for details on why we pivoted to a KVM-specific approach.
> 
> Key word is "biggest".  Relative to v10, there are many big changes.
> Highlights below (I can't remember everything that got changed at
> this point).
> 
> Tagged RFC as there are a lot of empty changelogs, and a lot of missing
> documentation.  And ideally, we'll have even more tests before merging.
> There are also several gaps/opens (to be discussed in tomorrow's PUCK).

I've pushed this to

  https://github.com/kvm-x86/linux/tree/guest_memfd

along with Isaku's fix for the lock ordering bug on top.

As discussed at PUCK, I'll apply fixes/tweaks/changes on top until development
stabilizes, and will only squash/fixup when we're ready to post v12 for broad
review.

Please "formally" post patches just like you normally would do, i.e. don't *just*
repond to the buggy mail (though that is also helpful).  Standalone patches make
it easier for me to manage things via lore/b4.

If you can, put gmem or guest_memfd inside the square braces, e.g.

  [PATCH gmem] KVM: <shortlog>

so that it's obvious the patch is intended for the guest_memfd branch.  For fixes,
please also be sure to use Fixes: tags and split patches to fix exactly one base
commit, again to make my life easier.

I'll likely add my own annotations when applying, e.g. [FIXUP] and whatnot, but
that's purely notes for myself for the future squash/rebase.

Thanks!