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From: David Vrabel <dvrabel@cantab.net>
To: Stefano Stabellini <sstabellini@kernel.org>,
	Julien Grall <julien@xen.org>
Cc: xen-devel@lists.xenproject.org, Bertrand.Marquis@arm.com,
	Luca Miccio <lucmiccio@gmail.com>,
	Stefano Stabellini <stefano.stabellini@xilinx.com>,
	Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Jan Beulich <jbeulich@suse.com>,
	George Dunlap <george.dunlap@citrix.com>, Wei Liu <wl@xen.org>,
	Juergen Gross <jgross@suse.com>
Subject: Re: [XEN PATCH 1/7] xen: introduce XENFEAT_xenstore_late_init
Date: Tue, 11 Jan 2022 11:01:55 +0000	[thread overview]
Message-ID: <e54f914d-a683-1855-1eeb-635df86f0d94@cantab.net> (raw)
In-Reply-To: <alpine.DEB.2.22.394.2201101340550.2060010@ubuntu-linux-20-04-desktop>



On 10/01/2022 22:55, Stefano Stabellini wrote:
> 
> I have a patch for Linux that if XENFEAT_xenstore_late_init is present
> makes Linux wait for an event notification before initializing xenstore:
> https://marc.info/?l=xen-devel&m=164160299315589
> 
> So with v1 of the Xen and Linux patches series:
> - Xen allocates the event channel at domain creation
> - Linux boots, sees XENFEAT_xenstore_late_init and wait for an event
> - init-dom0less later allocates the xenstore page
> - init-dom0less triggers the xenstore event channel
> - Linux receives the event and finishes the initialization, including
>    mapping the xenstore page

You can get this behaviour without the new feature.

- Xen allocates the event channel at domain creation
- Linux boots, sees HVM_PARAM_STORE_PFN is invalid and there's a 
xenstore event channel and waits for an event
- init-dom0less later allocates the xenstore page
- init-dom0less triggers the xenstore event channel
- Linux receives the event and finishes the initialization, including
    mapping the xenstore page-

David


  reply	other threads:[~2022-01-11 11:02 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-08  0:49 [XEN PATCH 0/7] dom0less PV drivers Stefano Stabellini
2022-01-08  0:49 ` [XEN PATCH 1/7] xen: introduce XENFEAT_xenstore_late_init Stefano Stabellini
2022-01-08  3:41   ` Julien Grall
2022-01-10 22:55     ` Stefano Stabellini
2022-01-11 11:01       ` David Vrabel [this message]
2022-01-11 22:52         ` Stefano Stabellini
2022-01-10  9:46   ` Jan Beulich
2022-01-10 23:08     ` Stefano Stabellini
2022-01-11  7:14       ` Jan Beulich
2022-01-11 22:51         ` Stefano Stabellini
2022-01-08  0:49 ` [XEN PATCH 2/7] xen: introduce _evtchn_alloc_unbound Stefano Stabellini
2022-01-10 10:25   ` Jan Beulich
2022-01-11 22:49     ` Stefano Stabellini
2022-01-12  7:42       ` Jan Beulich
2022-01-13  0:45         ` Stefano Stabellini
2022-01-08  0:49 ` [XEN PATCH 3/7] tools: add a late_init argument to xs_introduce_domain Stefano Stabellini
2022-01-08  2:35   ` Marek Marczykowski-Górecki
2022-01-13  0:49     ` Stefano Stabellini
2022-01-08  3:46   ` Julien Grall
2022-01-08  0:49 ` [XEN PATCH 4/7] xen: introduce xen,enhanced dom0less property Stefano Stabellini
2022-01-11  3:31   ` Volodymyr Babchuk
2022-01-11 23:03     ` Stefano Stabellini
2022-01-08  0:49 ` [XEN PATCH 5/7] xen/arm: configure dom0less domain for enabling xenstore after boot Stefano Stabellini
2022-01-08  0:49 ` [XEN PATCH 6/7] xenstored: do_introduce: handle the late_init case Stefano Stabellini
2022-01-08  2:39   ` Marek Marczykowski-Górecki
2022-01-13  0:51     ` Stefano Stabellini
2022-01-08  3:54   ` Julien Grall
2022-01-10 22:48     ` Stefano Stabellini
2022-01-08  0:49 ` [XEN PATCH 7/7] tools: add example application to initialize dom0less PV drivers Stefano Stabellini
2022-01-08  4:02   ` Julien Grall
2022-01-10 22:57     ` Stefano Stabellini

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