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[156.34.48.30]) by smtp.gmail.com with ESMTPSA id j16sm8994078qke.87.2020.07.31.09.56.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 31 Jul 2020 09:56:50 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1k1YKv-0027Bk-Hr; Fri, 31 Jul 2020 13:56:49 -0300 Date: Fri, 31 Jul 2020 13:56:49 -0300 From: Jason Gunthorpe To: Steven Sistare Cc: Matthew Wilcox , "Eric W. Biederman" , Anthony Yznaga , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, mhocko@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, arnd@arndb.de, keescook@chromium.org, gerg@linux-m68k.org, ktkhai@virtuozzo.com, christian.brauner@ubuntu.com, peterz@infradead.org, esyr@redhat.com, christian@kellner.me, areber@redhat.com, cyphar@cyphar.com Subject: Re: [RFC PATCH 0/5] madvise MADV_DOEXEC Message-ID: <20200731165649.GG24045@ziepe.ca> References: <20200730152250.GG23808@casper.infradead.org> <20200730171251.GI23808@casper.infradead.org> <63a7404c-e4f6-a82e-257b-217585b0277f@oracle.com> <20200730174956.GK23808@casper.infradead.org> <87y2n03brx.fsf@x220.int.ebiederm.org> <689d6348-6029-5396-8de7-a26bc3c017e5@oracle.com> <20200731152736.GP23808@casper.infradead.org> <9ba26063-0098-e796-9431-8c1d0c076ffc@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9ba26063-0098-e796-9431-8c1d0c076ffc@oracle.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Jul 31, 2020 at 12:11:52PM -0400, Steven Sistare wrote: > > Your preservation-across-exec use-case might or might not need the > > VMA to be mapped at the same address. > > It does. qemu registers memory with vfio which remembers the va's in kernel > metadata for the device. Once the memory is registered with vfio the VA doesn't matter, vfio will keep the iommu pointing at the same physical pages no matter where they are mapped. Jason