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Fri, 04 Sep 2020 13:09:12 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyX4Xhh11LgQlC31ujeG/EeQSnZyvInjG7xGIKM954pWhZp/ItPYfvo3YIfvnGUyMHrRxxzsg== X-Received: by 2002:a05:6402:1697:: with SMTP id a23mr10639629edv.195.1599250152631; Fri, 04 Sep 2020 13:09:12 -0700 (PDT) Received: from [192.168.10.150] ([93.56.170.5]) by smtp.gmail.com with ESMTPSA id bq24sm7048032ejb.27.2020.09.04.13.09.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 04 Sep 2020 13:09:11 -0700 (PDT) Subject: Re: [RESEND RFC PATCH 0/5] Remote mapping To: Andy Lutomirski , =?UTF-8?Q?Adalbert_Laz=c4=83r?= Cc: Linux-MM , Linux API , Andrew Morton , Alexander Graf , Stefan Hajnoczi , Jerome Glisse , =?UTF-8?Q?Mihai_Don=c8=9bu?= , Mircea Cirjaliu , Arnd Bergmann , Sargun Dhillon , Aleksa Sarai , Oleg Nesterov , Jann Horn , Kees Cook , Matthew Wilcox , Christian Brauner References: <20200904113116.20648-1-alazar@bitdefender.com> From: Paolo Bonzini Message-ID: Date: Fri, 4 Sep 2020 22:09:10 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pbonzini@redhat.com X-Mimecast-Spam-Score: 0.002 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Rspamd-Queue-Id: D5D4F1814B0C8 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 04/09/20 21:39, Andy Lutomirski wrote: > I'm a little concerned that it's actually too clever and that maybe a > more straightforward solution should be investigated. I personally > rather dislike the KVM model in which the guest address space mirrors > the host (QEMU) address space rather than being its own thing. In > particular, the current model means that extra-special-strange > mappings like SEV-encrypted memory are required to be present in the > QEMU page tables in order for the guest to see them. > > (If I had noticed that last bit before it went upstream, I would have > NAKked it. I would still like to see it deprecated and ideally > eventually removed from the kernel. We have absolutely no business > creating incoherent mappings like this.) NACK first and ask second, right Andy? I see that nothing has changed since Alan Cox left Linux. Paolo