linux-kernel - Re: [RFC PATCH v2 51/69] KVM: x86/mmu: Allow per-VM override of the TDP max page level

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Message-ID: <YO3/gvK9A3tgYfT6@google.com>
Date:   Tue, 13 Jul 2021 21:02:58 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     isaku.yamahata@...el.com, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, erdemaktas@...gle.com,
        Connor Kuehl <ckuehl@...hat.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        isaku.yamahata@...il.com,
        Sean Christopherson <sean.j.christopherson@...el.com>
Subject: Re: [RFC PATCH v2 51/69] KVM: x86/mmu: Allow per-VM override of the
 TDP max page level

On Tue, Jul 06, 2021, Paolo Bonzini wrote:
> On 03/07/21 00:04, isaku.yamahata@...el.com wrote:
> > From: Sean Christopherson <sean.j.christopherson@...el.com>
> > 
> > TODO: This is tentative patch.  Support large page and delete this patch.
> > 
> > Allow TDX to effectively disable large pages, as SEPT will initially
> > support only 4k pages.

...

> Seems good enough for now.

Looks like SNP needs a dynamic check, i.e. a kvm_x86_ops hook, to handle an edge
case in the RMP.  That's probably the better route given that this is a short-term
hack (hopefully :-D).