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Thu, 15 May 2025 15:00:42 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 6ELUG5oBJmhWPQAAD6G6ig (envelope-from ); Thu, 15 May 2025 15:00:42 +0000 Message-ID: <5911e91974db637d4a3395e60244c2c52b27b4b4.camel@suse.com> Subject: Re: [PATCH 0/2] dm mpath: Interface for explicit probing of active paths From: Martin Wilck To: Benjamin Marzinski Cc: Paolo Bonzini , Christoph Hellwig , Kevin Wolf , dm-devel@lists.linux.dev, Hanna Czenczek , Mikulas Patocka , snitzer@kernel.org, "Kernel Mailing List, Linux" , Hannes Reinecke Date: Thu, 15 May 2025 17:00:41 +0200 In-Reply-To: References: <20250429165018.112999-1-kwolf@redhat.com> <47dd225b433b0df585a25084a2e793344eeda239.camel@suse.com> <50beb356b4dc000446fd186ab754c87f386eaeae.camel@suse.com> <2f0fc8ef7d04c590893bd6d54a6c0c842c4b21d7.camel@suse.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Flag: NO X-Spam-Score: -4.30 X-Spam-Level: X-Spamd-Result: default: False [-4.30 / 50.00]; BAYES_HAM(-3.00)[99.99%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCPT_COUNT_SEVEN(0.00)[10]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:mid] On Thu, 2025-05-15 at 10:29 -0400, Benjamin Marzinski wrote: > On Thu, May 15, 2025 at 12:34:13PM +0200, Martin Wilck wrote: > >=20 > > However, I suppose that depends on the permissions with which the > > qemu > > process is started, no? Wouldn't qemu need CAP_SYS_RAWIO for PCI > > passthrough as well?=20 > >=20 > > I admit that I'm confused by the many indirections in qemu's scsi- > > block > > code flow. AFAICS qemu forwards everything except PRIN/PROUT to the > > kernel block device in "scsi-block" mode. Correct me if I'm wrong. > >=20 > > Anwyway, let's not forget that we're talking about the kernel here. > > While qemu is the main target application for this feature is > > created, > > any application can use it, and it may or may not run with > > CAP_SYS_RAWIO. >=20 > Maybe I'm missing your issue, but QEMU is just using DM's existing > ioctl > forwarding code, which was already designed for general use, and I > don't > see any capability issues with this patchset itself. I didn't mean it this way. I was rather musing about the question whether doing SG_IO on multipath devices by forwarding them to the current path makes sense. Sorry for the confusing post. Regards Martin