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[82.29.237.198]) by smtp.gmail.com with ESMTPSA id b13sm12098776wrf.86.2021.08.16.08.48.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Aug 2021 08:48:31 -0700 (PDT) Date: Mon, 16 Aug 2021 16:48:29 +0100 From: "Dr. David Alan Gilbert" To: Paolo Bonzini Cc: Ashish Kalra , qemu-devel@nongnu.org, thomas.lendacky@amd.com, brijesh.singh@amd.com, ehabkost@redhat.com, mst@redhat.com, richard.henderson@linaro.org, jejb@linux.ibm.com, tobin@ibm.com, dovmurik@linux.vnet.ibm.com, frankeh@us.ibm.com, kvm@vger.kernel.org Subject: Re: [RFC PATCH 00/13] Add support for Mirror VM. Message-ID: References: <20210816144413.GA29881@ashkalra_ubuntu_server> <20210816151349.GA29903@ashkalra_ubuntu_server> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/2.0.7 (2021-05-04) Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org * Paolo Bonzini (pbonzini@redhat.com) wrote: > On 16/08/21 17:13, Ashish Kalra wrote: > > > > I think that once the mirror VM starts booting and running the UEFI > > > > code, it might be only during the PEI or DXE phase where it will > > > > start actually running the MH code, so mirror VM probably still need > > > > to handles KVM_EXIT_IO when SEC phase does I/O, I can see PIC > > > > accesses and Debug Agent initialization stuff in SEC startup code. > > > That may be a design of the migration helper code that you were working > > > with, but it's not necessary. > > > > > Actually my comments are about a more generic MH code. > > I don't think that would be a good idea; designing QEMU's migration helper > interface to be as constrained as possible is a good thing. The migration > helper is extremely security sensitive code, so it should not expose itself > to the attack surface of the whole of QEMU. It's also odd in that it's provided by the guest and acting on behalf of the migration code; that's an unusually trusting relationship. Dave > Paolo > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK