xen-devel.lists.xenproject.org archive mirror
 help / color / mirror / Atom feed
From: "Jan Beulich" <JBeulich@suse.com>
To: Tamas K Lengyel <tamas@tklengyel.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
	xen-devel@lists.xen.org,
	Razvan Cojocaru <rcojocaru@bitdefender.com>,
	Corneliu ZUZU <czuzu@bitdefender.com>
Subject: Re: [PATCH 6/7] vm-event/arm: move hvm_event_cr->common vm_event_monitor_cr
Date: Wed, 22 Jun 2016 00:33:01 -0600	[thread overview]
Message-ID: <576A4D3D02000078000F772C@prv-mh.provo.novell.com> (raw)
In-Reply-To: <CABfawh=zfour1eFdwk_q21EfBDTY3OiJT4bcbA0owcCxvtnV=Q@mail.gmail.com>

>>> On 21.06.16 at 17:22, <tamas@tklengyel.com> wrote:
> On Jun 21, 2016 01:20, "Jan Beulich" <JBeulich@suse.com> wrote:
>>
>> >>> On 21.06.16 at 09:08, <czuzu@bitdefender.com> wrote:
>> > On 6/17/2016 11:25 AM, Corneliu ZUZU wrote:
>> >> On 6/16/2016 6:16 PM, Jan Beulich wrote:
>> >>>>>> On 16.06.16 at 16:12, <czuzu@bitdefender.com> wrote:
>> >>>> Prepare for ARM implementation of control-register write vm-events
>> >>>> by moving
>> >>>> X86-specific hvm_event_cr to the common-side.
>> >>>>
>> >>>> Signed-off-by: Corneliu ZUZU <czuzu@bitdefender.com>
>> >>>> ---
>> >>>>   xen/arch/x86/hvm/event.c        | 30 ------------------------------
>> >>>>   xen/arch/x86/hvm/hvm.c          |  2 +-
>> >>>>   xen/arch/x86/monitor.c          | 37
>> >>>> -------------------------------------
>> >>>>   xen/arch/x86/vm_event.c         |  2 +-
>> >>>>   xen/common/monitor.c            | 40
>> >>>> ++++++++++++++++++++++++++++++++++++++++
>> >>>>   xen/common/vm_event.c           | 31
> +++++++++++++++++++++++++++++++
>> >>>>   xen/include/asm-x86/hvm/event.h | 13 ++++---------
>> >>>>   xen/include/asm-x86/monitor.h   |  2 --
>> >>>>   xen/include/xen/monitor.h       |  4 ++++
>> >>>>   xen/include/xen/vm_event.h      | 10 ++++++++++
>> >>>>   10 files changed, 91 insertions(+), 80 deletions(-)
>> >>> Considering that there's no ARM file getting altered here at all,
>> >>> mentioning ARM in the subject is a little odd.
>> >>
>> >> This patch and the following one should be meld together.
>> >> I only split them to ease reviewing, sorry I forgot to mention that in
>> >> the cover letter.
>> >>
>> >>>
>> >>>> --- a/xen/common/monitor.c
>> >>>> +++ b/xen/common/monitor.c
>> >>>> @@ -62,6 +62,46 @@ int monitor_domctl(struct domain *d, struct
>> >>>> xen_domctl_monitor_op *mop)
>> >>>>         switch ( mop->event )
>> >>>>       {
>> >>>> +#if CONFIG_X86
>> >>> #ifdef please.
>> >> Ack.
>> >>>> +    case XEN_DOMCTL_MONITOR_EVENT_WRITE_CTRLREG:
>> >>>> +    {
>> >>>> +        struct arch_domain *ad = &d->arch;
>> >>> Peeking into the next patch I see that this stays there. Common code,
>> >>> however, shouldn't access ->arch sub-structures - respective fields
>> >>> should be moved out.
>> >>
>> >> Then we need to find a resolution that avoids code duplication.
>> >> The code is the same, but those bits that are currently on the arch
>> >> side (arch.monitor.write_ctrlreg_*) cannot be moved to common as they
>> >> are, since their -number- might differ from arch-to-arch.
>> >> But we could:
>> >> - in public/vm_event.h, besides the VM_EVENT_X86_* and VM_EVENT_ARM_*
>> >> defines (wcr index), also have
>> >>     #define VM_EVENT_X86_CR_COUNT        4
>> >>     #define VM_EVENT_ARM_CR_COUNT      4
>> >> - move the 3 write_ctrlreg_{enabled,sync,onchangeonly} fields from
>> >> arch_domain to domain (common) and make them 8-bits wide each for now
>> >> (widened more in the future if the need arises)
>> >> - let monitor_ctrlreg_bitmask() macro to be architecture-dependent and
>> >> use the introduced VM_EVENT_<arch>_CR_COUNT
>> >>
>> >> Tamas, we also talked on this matter @ some point (when I sent the
>> >> patches that moved vm-event parts to common). What do you think of the
>> >> above?
>>
>> I don't really care about the specifics, my only request is what I
>> already voiced: Common code should not access arch-specific
>> fields. Having the field to hold the control register bits common,
>> but the definitions for the individual bits arch-specific is perfectly
>> fine for this (assuming that these per-arch definitions then again
>> don't get used in common code).
> 
> As Jan says it would be fine to have the holder field on the common struct
> but IMHO it wouldn't be easier to follow the logic that way and the only
> benefit is reducing code duplication a little bit. I think for now it is
> acceptable to just rather have some code duplication.

Code duplication isn't the main issue here. Inviting further
conceptually wrong code additions (accessing per-arch fields from
common code), by setting a(nother) bad precedent, is what I want
to avoid from the beginning.

Jan

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel

  reply	other threads:[~2016-06-22  6:33 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-16 14:04 [PATCH 0/7] vm-event: Implement ARM support for control-register writes Corneliu ZUZU
2016-06-16 14:06 ` [PATCH 1/7] minor (formatting) fixes Corneliu ZUZU
2016-06-16 14:24   ` Jan Beulich
2016-06-16 19:19     ` Corneliu ZUZU
2016-06-17  7:06       ` Jan Beulich
2016-06-17 10:46         ` Corneliu ZUZU
2016-06-16 16:02   ` Tamas K Lengyel
2016-06-17  8:33     ` Corneliu ZUZU
2016-06-17  8:36       ` Razvan Cojocaru
2016-06-17  9:29         ` Andrew Cooper
2016-06-17  9:35           ` Jan Beulich
2016-06-17  9:33         ` Jan Beulich
2016-06-17  9:36           ` Razvan Cojocaru
2016-06-17  9:40             ` Jan Beulich
2016-06-17  9:42               ` Razvan Cojocaru
2016-06-17 19:05           ` Tamas K Lengyel
2016-06-16 14:07 ` [PATCH 2/7] vm-event: VM_EVENT_FLAG_DENY requires VM_EVENT_FLAG_VCPU_PAUSED Corneliu ZUZU
2016-06-16 16:11   ` Tamas K Lengyel
2016-06-17  8:43     ` Corneliu ZUZU
2016-06-21 11:26     ` Corneliu ZUZU
2016-06-21 15:09       ` Tamas K Lengyel
2016-06-22  8:34         ` Corneliu ZUZU
2016-06-16 14:08 ` [PATCH 3/7] vm-event: introduce vm_event_vcpu_enter Corneliu ZUZU
2016-06-16 14:51   ` Jan Beulich
2016-06-16 20:10     ` Corneliu ZUZU
2016-06-16 20:33       ` Razvan Cojocaru
2016-06-17 10:41         ` Corneliu ZUZU
2016-06-17  7:17       ` Jan Beulich
2016-06-17 11:13         ` Corneliu ZUZU
2016-06-17 11:27           ` Jan Beulich
2016-06-17 12:13             ` Corneliu ZUZU
2016-06-16 16:17   ` Tamas K Lengyel
2016-06-17  9:19     ` Corneliu ZUZU
2016-06-17  8:55   ` Julien Grall
2016-06-17 11:40     ` Corneliu ZUZU
2016-06-17 13:22       ` Julien Grall
2016-06-16 14:09 ` [PATCH 4/7] vm-event/x86: use vm_event_vcpu_enter properly Corneliu ZUZU
2016-06-16 15:00   ` Jan Beulich
2016-06-16 20:20     ` Corneliu ZUZU
2016-06-17  7:20       ` Jan Beulich
2016-06-17 11:23         ` Corneliu ZUZU
2016-06-16 16:27   ` Tamas K Lengyel
2016-06-17  9:24     ` Corneliu ZUZU
2016-06-16 14:10 ` [PATCH 5/7] x86: replace monitor_write_data.do_write with enum Corneliu ZUZU
2016-06-16 14:12 ` [PATCH 6/7] vm-event/arm: move hvm_event_cr->common vm_event_monitor_cr Corneliu ZUZU
2016-06-16 15:16   ` Jan Beulich
2016-06-17  8:25     ` Corneliu ZUZU
2016-06-17  8:38       ` Jan Beulich
2016-06-17 11:31         ` Corneliu ZUZU
2016-06-21  7:08       ` Corneliu ZUZU
2016-06-21  7:20         ` Jan Beulich
2016-06-21 15:22           ` Tamas K Lengyel
2016-06-22  6:33             ` Jan Beulich [this message]
2016-06-16 16:55   ` Tamas K Lengyel
2016-06-17 10:37     ` Corneliu ZUZU
2016-06-16 14:13 ` [PATCH 7/7] vm-event/arm: implement support for control-register write vm-events Corneliu ZUZU
2016-06-16 14:26   ` Julien Grall
2016-06-16 19:24     ` Corneliu ZUZU
2016-06-16 21:28       ` Julien Grall
2016-06-17 11:46         ` Corneliu ZUZU
2016-06-16 16:49   ` Julien Grall
2016-06-17 10:36     ` Corneliu ZUZU
2016-06-17 13:18       ` Julien Grall
2016-06-22 16:35       ` Corneliu ZUZU
2016-06-22 17:17         ` Julien Grall
2016-06-22 18:39           ` Corneliu ZUZU
2016-06-22 19:37             ` Corneliu ZUZU
2016-06-22 19:41               ` Julien Grall
2016-06-23  5:31                 ` Corneliu ZUZU
2016-06-23  5:49                   ` Corneliu ZUZU
2016-06-23 11:11                     ` Julien Grall
2016-06-24  9:32                       ` Corneliu ZUZU
2016-06-23 11:00           ` Julien Grall

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=576A4D3D02000078000F772C@prv-mh.provo.novell.com \
    --to=jbeulich@suse.com \
    --cc=andrew.cooper3@citrix.com \
    --cc=czuzu@bitdefender.com \
    --cc=rcojocaru@bitdefender.com \
    --cc=tamas@tklengyel.com \
    --cc=xen-devel@lists.xen.org \
    --subject='Re: [PATCH 6/7] vm-event/arm: move hvm_event_cr->common vm_event_monitor_cr' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).