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([2001:b07:6468:f312:5e2c:eb9a:a8b6:fd3e]) by smtp.gmail.com with ESMTPSA id c9sm10582239wrp.73.2020.12.06.02.19.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 06 Dec 2020 02:19:22 -0800 (PST) Subject: Re: [PATCH v8 12/18] KVM: SVM: Add support for static allocation of unified Page Encryption Bitmap. To: Ashish Kalra Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, joro@8bytes.org, bp@suse.de, Thomas.Lendacky@amd.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, srutherford@google.com, rientjes@google.com, venu.busireddy@oracle.com, brijesh.singh@amd.com References: <17c14245a404ff679253313ffe899c5f4e966717.1588711355.git.ashish.kalra@amd.com> <617d3cba-cbe0-0f18-bdf2-e73a70e472d6@redhat.com> <20201204213852.GA1424@ashkalra_ubuntu_server> From: Paolo Bonzini Message-ID: <4e60a01d-dfc8-bc4f-e3d2-628d69f370fa@redhat.com> Date: Sun, 6 Dec 2020 11:19:21 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20201204213852.GA1424@ashkalra_ubuntu_server> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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