Re: [PATCH v2 2/2] xen: implement VCPUOP_register_runstate_phys_memory_area

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From: Andrii Anisov <andrii.anisov@gmail.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	Wei Liu <wei.liu2@citrix.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	George Dunlap <George.Dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Ian Jackson <Ian.Jackson@eu.citrix.com>, Tim Deegan <tim@xen.org>,
	Julien Grall <julien.grall@arm.com>,
	xen-devel <xen-devel@lists.xenproject.org>,
	"andrii_anisov@epam.com" <andrii_anisov@epam.com>,
	Roger Pau Monne <roger.pau@citrix.com>
Subject: Re: [PATCH v2 2/2] xen: implement VCPUOP_register_runstate_phys_memory_area
Date: Wed, 15 May 2019 11:44:39 +0300	[thread overview]
Message-ID: <9a285538-2c98-2b3d-9c1c-f7a21f9de890@gmail.com> (raw)
In-Reply-To: <5CDAC779020000780022EBA7@prv1-mh.provo.novell.com>

Hello Jan,

On 14.05.19 16:49, Jan Beulich wrote:
> If this was a concern only for newly written code, this would be fine.
> But you need to make sure all existing code also continues to work
> with whatever new interface you implement.

And that is one more reason why I tend to introduce the new interface in parallel to be fully independent from the old one.
But not do a mixed implementation as you and Julien suggest.

> Just because a kernel
> uses your new physical address based mechanism doesn't mean the
> boot loader knows to unregister what it has registered.

As Julien already said, the current interface has an implicit mechanism to unregister runstate area.
Also if the bootloader misses unregistering runstate area with the current interface, we already have the broken system.
So it is really up to the guest system to take care about its possible transitions.

-- 
Sincerely,
Andrii Anisov.

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

WARNING: multiple messages have this Message-ID (diff)

From: Andrii Anisov <andrii.anisov@gmail.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	Wei Liu <wei.liu2@citrix.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	George Dunlap <George.Dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Ian Jackson <Ian.Jackson@eu.citrix.com>, Tim Deegan <tim@xen.org>,
	Julien Grall <julien.grall@arm.com>,
	xen-devel <xen-devel@lists.xenproject.org>,
	"andrii_anisov@epam.com" <andrii_anisov@epam.com>,
	Roger Pau Monne <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH v2 2/2] xen: implement VCPUOP_register_runstate_phys_memory_area
Date: Wed, 15 May 2019 11:44:39 +0300	[thread overview]
Message-ID: <9a285538-2c98-2b3d-9c1c-f7a21f9de890@gmail.com> (raw)
Message-ID: <20190515084439.fn0Ttp6peK4E8Yxyehu0ymQ8DSjCQkNEGvcjd-AMiVc@z> (raw)
In-Reply-To: <5CDAC779020000780022EBA7@prv1-mh.provo.novell.com>

Hello Jan,

On 14.05.19 16:49, Jan Beulich wrote:
> If this was a concern only for newly written code, this would be fine.
> But you need to make sure all existing code also continues to work
> with whatever new interface you implement.

And that is one more reason why I tend to introduce the new interface in parallel to be fully independent from the old one.
But not do a mixed implementation as you and Julien suggest.

> Just because a kernel
> uses your new physical address based mechanism doesn't mean the
> boot loader knows to unregister what it has registered.

As Julien already said, the current interface has an implicit mechanism to unregister runstate area.
Also if the bootloader misses unregistering runstate area with the current interface, we already have the broken system.
So it is really up to the guest system to take care about its possible transitions.

-- 
Sincerely,
Andrii Anisov.

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

next prev parent reply	other threads:[~2019-05-15  8:44 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-23  8:10 [PATCH v2 0/2] Introduce runstate area registration with phys address Andrii Anisov
2019-04-23  8:10 ` [PATCH v2 1/2] xen: introduce VCPUOP_register_runstate_phys_memory_area hypercall Andrii Anisov
2019-04-23  8:10   ` [Xen-devel] " Andrii Anisov
2019-05-08 10:10   ` George Dunlap
2019-05-08 10:10     ` [Xen-devel] " George Dunlap
2019-04-23  8:10 ` [PATCH v2 2/2] xen: implement VCPUOP_register_runstate_phys_memory_area Andrii Anisov
2019-04-23  8:10   ` [Xen-devel] " Andrii Anisov
2019-05-08 15:40   ` Julien Grall
2019-05-08 15:40     ` [Xen-devel] " Julien Grall
2019-05-09  9:27     ` Jan Beulich
2019-05-09  9:27       ` [Xen-devel] " Jan Beulich
2019-05-14  9:35       ` Julien Grall
2019-05-14  9:35         ` [Xen-devel] " Julien Grall
2019-05-14  9:48         ` Jan Beulich
2019-05-14  9:48           ` [Xen-devel] " Jan Beulich
2019-05-14 11:23           ` Julien Grall
2019-05-14 11:23             ` [Xen-devel] " Julien Grall
2019-05-14 11:29             ` Jan Beulich
2019-05-14 11:29               ` [Xen-devel] " Jan Beulich
2019-05-13 12:30     ` Andrii Anisov
2019-05-13 12:30       ` [Xen-devel] " Andrii Anisov
2019-05-14  9:58       ` Julien Grall
2019-05-14  9:58         ` [Xen-devel] " Julien Grall
2019-05-14 10:08         ` Andrii Anisov
2019-05-14 10:08           ` [Xen-devel] " Andrii Anisov
2019-05-14 11:24           ` Julien Grall
2019-05-14 11:24             ` [Xen-devel] " Julien Grall
2019-05-14 11:45             ` Andrii Anisov
2019-05-14 11:45               ` [Xen-devel] " Andrii Anisov
2019-05-14 12:02               ` Jan Beulich
2019-05-14 12:02                 ` [Xen-devel] " Jan Beulich
2019-05-14 13:05                 ` Andrii Anisov
2019-05-14 13:05                   ` [Xen-devel] " Andrii Anisov
2019-05-14 13:49                   ` Julien Grall
2019-05-14 13:49                     ` [Xen-devel] " Julien Grall
2019-05-15  9:04                     ` Andrii Anisov
2019-05-15  9:04                       ` [Xen-devel] " Andrii Anisov
2019-05-15 10:31                       ` Julien Grall
2019-05-15 10:31                         ` [Xen-devel] " Julien Grall
2019-05-14 13:49                   ` Jan Beulich
2019-05-14 13:49                     ` [Xen-devel] " Jan Beulich
2019-05-15  8:44                     ` Andrii Anisov [this message]
2019-05-15  8:44                       ` Andrii Anisov
2019-05-15 11:59                       ` Jan Beulich
2019-05-15 11:59                         ` [Xen-devel] " Jan Beulich
2019-05-16 12:09   ` Jan Beulich
2019-05-16 12:09     ` [Xen-devel] " Jan Beulich
2019-05-16 13:30     ` Andrii Anisov
2019-05-16 13:30       ` [Xen-devel] " Andrii Anisov
2019-05-16 13:30     ` Andrii Anisov
2019-05-16 13:30       ` [Xen-devel] " Andrii Anisov
2019-05-16 13:48       ` Julien Grall
2019-05-16 13:48         ` [Xen-devel] " Julien Grall
2019-05-16 14:25         ` Andrii Anisov
2019-05-16 14:25           ` [Xen-devel] " Andrii Anisov
2019-05-16 14:28           ` Julien Grall
2019-05-16 14:28             ` [Xen-devel] " Julien Grall
2019-05-16 14:29             ` Andrii Anisov
2019-05-16 14:29               ` [Xen-devel] " Andrii Anisov
     [not found] ` <fa126315-31af-854e-817a-8640b431c82b@arm.com>
     [not found]   ` <CAC1WxdiMzAq5hRC-mhRQuFDs7z_Hj5w7VAy52ec87SJQOGmp3w@mail.gmail.com>
     [not found]     ` <a28f95a1-d9da-2caf-f4b4-013100176b02@arm.com>
     [not found]       ` <090ce8cc-f329-fe54-4894-b7f12e3cd5a6@gmail.com>
2019-05-08 13:39         ` [PATCH v2 0/2] Introduce runstate area registration with phys address Julien Grall
2019-05-08 13:39           ` [Xen-devel] " Julien Grall
2019-05-08 13:54           ` Andrii Anisov
2019-05-08 13:54             ` [Xen-devel] " Andrii Anisov
2019-05-08 14:31             ` Julien Grall
2019-05-08 14:31               ` [Xen-devel] " Julien Grall
2019-05-08 16:01               ` Andrii Anisov
2019-05-08 16:01                 ` [Xen-devel] " Andrii Anisov
2019-05-13 10:50                 ` Julien Grall
2019-05-13 10:50                   ` [Xen-devel] " Julien Grall
2019-05-13 14:34                   ` Andrii Anisov
2019-05-13 14:34                     ` [Xen-devel] " Andrii Anisov
2019-05-08 13:59 ` Julien Grall
2019-05-13 10:15   ` Andrii Anisov
2019-05-13 11:16     ` Julien Grall
2019-05-13 14:14       ` Andrii Anisov
2019-05-13 14:34         ` Julien Grall
2019-05-13 15:29           ` Andrii Anisov
2019-05-13 15:31             ` Julien Grall
2019-05-13 15:38               ` Andrii Anisov
2019-05-13 15:40                 ` Julien Grall
2019-05-13 15:42                   ` Andrii Anisov
2019-05-13 15:45                     ` Julien Grall
2019-05-13 16:05                       ` Andrii Anisov

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