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Tsirkin" , Eduardo Habkost , Anthony PERARD , xen-devel@lists.xenproject.org Subject: Re: [PATCH 0/4] Xen: Add Q35 initial support for HVM guests Message-ID: References: <20260313164649.794591-1-thierry.escande@vates.tech> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="82oef0c++DDw9SXs" Content-Disposition: inline In-Reply-To: <20260313164649.794591-1-thierry.escande@vates.tech> Received-SPF: pass client-ip=202.12.124.152; envelope-from=marmarek@invisiblethingslab.com; helo=fhigh-b1-smtp.messagingengine.com X-Spam_score_int: -10 X-Spam_score: -1.1 X-Spam_bar: - X-Spam_report: (-1.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.819, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.903, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --82oef0c++DDw9SXs Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Date: Sat, 14 Mar 2026 15:16:15 +0100 From: Marek =?utf-8?Q?Marczykowski-G=C3=B3recki?= To: Thierry Escande Cc: qemu-devel@nongnu.org, Paolo Bonzini , Richard Henderson , "Michael S. Tsirkin" , Eduardo Habkost , Anthony PERARD , xen-devel@lists.xenproject.org Subject: Re: [PATCH 0/4] Xen: Add Q35 initial support for HVM guests On Fri, Mar 13, 2026 at 04:46:56PM +0000, Thierry Escande wrote: > This patch series introduces Q35 chipset support for Xen HVM guests. This= is > based on the work from Alexey Gerasimenko (See patchset [1] for reference= ). >=20 > This series does not implement device passthrough as this will need more = work > on the Xen side to support multiple PCI buses. Since Q35 chipset does not > support device hotplugging and with current Xen mechanism for device > passthrough, they have to be plugged to a new PCIe root port, i.e. not th= e PCI > bus 0. I always found it weird that Xen does hot-plugging of PCI passthrough devices... Wouldn't it be easier to change this (connect them from the very start, via QEMU cmdline) and declare hotplug as unsupported (at least at this time)? I realize it's more complex change at the toolstack side, but overall may simplify things and maybe even improve reliability. In any case, it's probably not worth blocking initial support on this. --=20 Best Regards, Marek Marczykowski-G=C3=B3recki Invisible Things Lab --82oef0c++DDw9SXs Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhrpukzGPukRmQqkK24/THMrX1ywFAmm1bbAACgkQ24/THMrX 1ywG2Qf9HeEIoighs7imZKLP80u2BXOmsxS5olpQKk2WNfonDrnzngS/WalGuUoA 2/oVsk8aQFNGL5YXl7VKSLnwT4IZCstMtK+XhuqDVHoEdx+rUnrOoTzbNs55V9nT LjQzPWgL02G6RwhZ2F5XK03S4jGNNI07Un1G2pFAQTM4uTobQAJb0mC67sxE8En+ GP73r7svgXwFGvZ1Gtm/50jPvyUUIzJ5MNaaT1p+OorQ9EKeSvj15C77ceEXEqxb M5jGaoCde5GhtKz5SOj8UQaGqgSyXh4LcLEcLdfXmnTwtF08aIbMKdio9B0VOaO/ xvVBzhNeVJjp43BbOcazmDEk2dQU7Q== =NocA -----END PGP SIGNATURE----- --82oef0c++DDw9SXs--