linux-kernel - Re: [PATCH v8 12/18] KVM: SVM: Add support for static allocation of unified Page Encryption Bitmap.

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Message-ID: <4e60a01d-dfc8-bc4f-e3d2-628d69f370fa@redhat.com>
Date:   Sun, 6 Dec 2020 11:19:21 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Ashish Kalra <ashish.kalra@....com>
Cc:     tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        joro@...tes.org, bp@...e.de, Thomas.Lendacky@....com,
        x86@...nel.org, kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        srutherford@...gle.com, rientjes@...gle.com,
        venu.busireddy@...cle.com, brijesh.singh@....com
Subject: Re: [PATCH v8 12/18] KVM: SVM: Add support for static allocation of
 unified Page Encryption Bitmap.

On 04/12/20 22:38, Ashish Kalra wrote:
> Earlier we used to dynamic resizing of the page encryption bitmap based
> on the guest hypercall, but potentially a malicious guest can make a hypercall
> which can trigger a really large memory allocation on the host side and may
> eventually cause denial of service.
> 
> Hence now we don't do dynamic resizing of the page encryption bitmap as
> per the hypercall and allocate it statically based on guest memory
> allocation by walking through memslots and computing it's size.
> 
> I will add the above comment to the fresh series of the patch-set i am
> going to post.

Sounds good, thanks.  If there are no other changes I can include this 
in the commit message myself.

Paolo