From: Razvan Cojocaru <rcojocaru@bitdefender.com>
To: Jan Beulich <JBeulich@suse.com>, Tamas K Lengyel <tamas@tklengyel.com>
Cc: Xen-devel <xen-devel@lists.xenproject.org>,
Julien Grall <julien.grall@arm.com>,
Stefano Stabellini <sstabellini@kernel.org>
Subject: Re: [PATCH v4 5/8] arm/vm_event: get/set registers
Date: Thu, 2 Jun 2016 11:26:34 +0300 [thread overview]
Message-ID: <8da9b1a2-450a-62e5-2f0c-89f58a7857be@bitdefender.com> (raw)
In-Reply-To: <574FFDDA02000078000F0B92@prv-mh.provo.novell.com>
On 06/02/2016 10:35 AM, Jan Beulich wrote:
> The criteria for inclusion or exclusion should
> follow a predictable model. I.e. if someone comes along and says
> "I need register Y", then there should be rules that (s)he can apply
> up front to determine what (at least in the vast majority of cases)
> the response is going to be. You saying "I need only this arbitrary
> subset of registers" is completely in-transparent, as it leaves open
> why this is so, and why this would also be so for others. I.e. you'd
> at least need to answer the question why (as an example) you
> need x5 included, but not x25, despite both registers being equal
> from an architecture pov. An answer like "My application gets away
> with it" is not acceptable here.
There will be trade-offs. Again, my preference would be to have a
multi-page ring buffer with all the VCPU context included in the
request, always. This would work best as far as both completeness and
performance goes.
But that is obviously not a trivial change and I can see how Tamas would
prefer to get things done sooner along the lines of the pre-existing
design (whatever its merits and demerits are).
As long as we're using a smaller ring buffer, the answer (at least as
I've meant it) is not "_my_ application gets away with it" - which is
indeed not the most reasonable statement, but "_current_ introspection
applications - of which my application is one of - don't need more than
this at this time". So in the spirit of "the rest of the context is a
hypercall away" + we don't have that much space available in the ring
buffer, the whole context is not included. The assumption here being
that once another application (or even our application, at a later time)
needs to enlarge the set of registers sent with a request, it will be
requested here and we can discuss what that entails.
Thanks,
Razvan
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next prev parent reply other threads:[~2016-06-02 8:26 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-29 22:37 [PATCH v4 1/8] monitor: Rename vm_event_monitor_get_capabilities Tamas K Lengyel
2016-05-29 22:37 ` [PATCH v4 2/8] monitor: Rename vm_event_monitor_guest_request Tamas K Lengyel
2016-05-30 7:05 ` Razvan Cojocaru
2016-05-30 13:51 ` Jan Beulich
2016-05-29 22:37 ` [PATCH v4 3/8] monitor: Rename hvm/event to hvm/monitor Tamas K Lengyel
2016-05-30 7:08 ` Razvan Cojocaru
2016-05-30 13:53 ` Jan Beulich
2016-05-29 22:37 ` [PATCH v4 4/8] monitor: ARM SMC events Tamas K Lengyel
2016-06-01 11:37 ` Julien Grall
[not found] ` <CABfawhmO9tUG3-OcorfwqdOgZTkjoUk+u=dHySGonBDvobqyKw@mail.gmail.com>
[not found] ` <CABfawhmK2GAmQqZMhrgjYzeUZ_XaoyRUPuJxyPK5LJEHwsp5SA@mail.gmail.com>
[not found] ` <CABfawh=J1fwinTYKGvJNrFPOsGLSXz6U3GE8fxPz3-KsXSWfbQ@mail.gmail.com>
[not found] ` <CABfawhn7zvE=hn0hq1ryH+sW-jdkAXgZM1C2KxwZVUE8pbp8cQ@mail.gmail.com>
2016-06-01 15:41 ` Tamas K Lengyel
2016-06-02 14:23 ` Julien Grall
2016-06-02 22:31 ` Tamas K Lengyel
2016-07-04 19:13 ` Tamas K Lengyel
2016-07-04 20:02 ` Julien Grall
2016-07-04 21:05 ` Tamas K Lengyel
2016-07-05 9:58 ` Julien Grall
2016-05-29 22:37 ` [PATCH v4 5/8] arm/vm_event: get/set registers Tamas K Lengyel
2016-05-30 7:09 ` Razvan Cojocaru
2016-05-30 11:50 ` Jan Beulich
2016-05-30 19:47 ` Tamas K Lengyel
2016-05-30 20:20 ` Julien Grall
2016-05-30 20:37 ` Tamas K Lengyel
2016-05-30 20:46 ` Razvan Cojocaru
2016-05-30 20:53 ` Tamas K Lengyel
2016-05-30 21:35 ` Julien Grall
2016-05-30 21:41 ` Tamas K Lengyel
2016-05-31 7:54 ` Jan Beulich
2016-05-31 8:06 ` Razvan Cojocaru
2016-05-31 8:30 ` Jan Beulich
2016-05-31 16:20 ` Tamas K Lengyel
2016-05-31 7:48 ` Jan Beulich
2016-05-31 16:28 ` Tamas K Lengyel
2016-06-01 8:41 ` Jan Beulich
2016-06-01 11:24 ` Julien Grall
2016-06-01 18:21 ` Tamas K Lengyel
2016-06-01 19:34 ` Razvan Cojocaru
2016-06-01 19:43 ` Julien Grall
2016-06-02 7:35 ` Jan Beulich
2016-06-02 8:26 ` Razvan Cojocaru [this message]
2016-06-02 9:38 ` Jan Beulich
2016-06-02 9:42 ` Razvan Cojocaru
2016-06-01 19:38 ` Julien Grall
2016-06-01 19:49 ` Julien Grall
2016-06-01 19:50 ` Tamas K Lengyel
2016-05-29 22:37 ` [PATCH v4 6/8] tools/libxc: add xc_monitor_privileged_call Tamas K Lengyel
2016-05-29 22:37 ` [PATCH v4 7/8] tools/xen-access: add test-case for ARM SMC Tamas K Lengyel
2016-05-30 9:56 ` Wei Liu
2016-05-29 22:37 ` [PATCH v4 8/8] x86/vm_event: Add HVM debug exception vm_events Tamas K Lengyel
2016-05-30 7:29 ` Razvan Cojocaru
2016-05-30 14:16 ` Jan Beulich
2016-05-30 20:13 ` Tamas K Lengyel
2016-05-30 20:58 ` Andrew Cooper
2016-05-31 7:59 ` Jan Beulich
2016-06-01 21:46 ` Tamas K Lengyel
2016-06-01 22:17 ` Andrew Cooper
2016-06-02 0:01 ` Tamas K Lengyel
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