From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>, Wei Liu <wl@xen.org>,
<xen-devel@lists.xenproject.org>
Subject: Re: [PATCH v3 06/11] x86/hvm: allowing registering EOI callbacks for GSIs
Date: Thu, 8 Apr 2021 17:06:41 +0200 [thread overview]
Message-ID: <YG8cAXkXCArrKnpD@Air-de-Roger> (raw)
In-Reply-To: <8d088ae2-e8a7-7818-5ee8-5ed95ac260c1@suse.com>
On Thu, Apr 08, 2021 at 04:31:59PM +0200, Jan Beulich wrote:
> On 08.04.2021 14:52, Roger Pau Monné wrote:
> > On Wed, Apr 07, 2021 at 05:51:14PM +0200, Jan Beulich wrote:
> >> On 31.03.2021 12:32, Roger Pau Monne wrote:
> >>> --- a/xen/arch/x86/hvm/irq.c
> >>> +++ b/xen/arch/x86/hvm/irq.c
> >>> +void hvm_gsi_unregister_callback(struct domain *d, unsigned int gsi,
> >>> + struct hvm_gsi_eoi_callback *cb)
> >>> +{
> >>> + struct hvm_irq *hvm_irq = hvm_domain_irq(d);
> >>> + const struct list_head *tmp;
> >>> +
> >>> + if ( gsi >= hvm_irq->nr_gsis )
> >>> + {
> >>> + ASSERT_UNREACHABLE();
> >>> + return;
> >>> + }
> >>> +
> >>> + write_lock(&hvm_irq->gsi_callbacks_lock);
> >>> + list_for_each ( tmp, &hvm_irq->gsi_callbacks[gsi] )
> >>> + if ( tmp == &cb->list )
> >>> + {
> >>> + list_del(&cb->list);
> >>> + break;
> >>> + }
> >>> + write_unlock(&hvm_irq->gsi_callbacks_lock);
> >>> +}
> >>
> >> Perhaps somehow flag, at least in debug builds, if the callback
> >> wasn#t found?
> >
> > I've added a debug printf here to warn if the callback is not found,
> > but I see it triggering because hpet_set_timer will call
> > destroy_periodic_time and create_periodic_time and thus two calls will
> > be made to hvm_gsi_unregister_callback. This is fine, but adding a
> > message there gets too verbose, so I will drop it and leave the code
> > as-is.
> >
> > I don't see a problem with calling destroy_periodic_time multiple
> > times even if the timer was not active, and that shouldn't result in a
> > message being printed.
>
> If destroy_periodic_time() is to remain the only caller, I guess I
> agree. Other (future) callers may then need this function to gain
> a return value indicating whether the callback was actually found.
There's also pt_irq_destroy_bind which likely cares about the return
value, so let's return a value from hvm_gsi_unregister_callback and
check it in pt_irq_destroy_bind.
Thanks, Roger.
next prev parent reply other threads:[~2021-04-08 15:07 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-31 10:32 [PATCH v3 00/11] x86/intr: introduce EOI callbacks and fix vPT Roger Pau Monne
2021-03-31 10:32 ` [PATCH v3 01/11] x86/hvm: drop vcpu parameter from vlapic EOI callbacks Roger Pau Monne
2021-03-31 16:02 ` Jan Beulich
2021-03-31 16:24 ` Andrew Cooper
2021-04-01 9:12 ` Roger Pau Monné
2021-04-01 11:06 ` Jan Beulich
2021-04-07 7:41 ` Roger Pau Monné
2021-04-07 8:19 ` Jan Beulich
2021-03-31 10:32 ` [PATCH v3 02/11] x86/hvm: drop domain parameter from vioapic/vpic " Roger Pau Monne
2021-03-31 16:04 ` Jan Beulich
2021-04-01 9:15 ` Roger Pau Monné
2021-04-01 9:28 ` Jan Beulich
2021-03-31 10:32 ` [PATCH v3 03/11] x86/vlapic: introduce an EOI callback mechanism Roger Pau Monne
2021-03-31 11:47 ` Andrew Cooper
2021-03-31 12:50 ` Roger Pau Monné
2021-04-07 14:55 ` Jan Beulich
2021-04-07 16:27 ` Roger Pau Monné
2021-04-08 6:20 ` Jan Beulich
2021-04-08 9:12 ` Roger Pau Monné
2021-04-08 10:49 ` Jan Beulich
2021-04-08 10:56 ` Roger Pau Monné
2021-03-31 10:32 ` [PATCH v3 04/11] x86/vmsi: use the newly introduced EOI callbacks Roger Pau Monne
2021-04-07 14:59 ` Jan Beulich
2021-03-31 10:32 ` [PATCH v3 05/11] x86/vioapic: switch to use the EOI callback mechanism Roger Pau Monne
2021-04-07 15:19 ` Jan Beulich
2021-04-07 16:46 ` Roger Pau Monné
2021-04-08 6:27 ` Jan Beulich
2021-04-08 8:59 ` Roger Pau Monné
2021-04-08 10:52 ` Jan Beulich
2021-03-31 10:32 ` [PATCH v3 06/11] x86/hvm: allowing registering EOI callbacks for GSIs Roger Pau Monne
2021-04-07 15:51 ` Jan Beulich
2021-04-07 17:08 ` Roger Pau Monné
2021-04-08 6:34 ` Jan Beulich
2021-04-15 16:04 ` Roger Pau Monné
2021-04-16 7:29 ` Jan Beulich
2021-04-19 8:31 ` Roger Pau Monné
2021-04-08 12:52 ` Roger Pau Monné
2021-04-08 14:31 ` Jan Beulich
2021-04-08 15:06 ` Roger Pau Monné [this message]
2021-03-31 10:32 ` [PATCH v3 07/11] x86/dpci: move code Roger Pau Monne
2021-03-31 10:33 ` [PATCH v3 08/11] x86/dpci: switch to use a GSI EOI callback Roger Pau Monne
2021-04-08 14:49 ` Jan Beulich
2021-04-08 15:23 ` Roger Pau Monné
2021-03-31 10:33 ` [PATCH v3 09/11] x86/vpt: switch interrupt injection model Roger Pau Monne
2021-04-14 10:28 ` Jan Beulich
2021-04-14 13:37 ` Roger Pau Monné
2021-04-14 14:05 ` Jan Beulich
2021-04-14 14:20 ` Roger Pau Monné
2021-03-31 10:33 ` [PATCH v3 10/11] x86/vpt: remove vPT timers per-vCPU lists Roger Pau Monne
2021-04-14 10:38 ` Jan Beulich
2021-03-31 10:33 ` [PATCH v3 11/11] x86/vpt: introduce a per-vPT lock Roger Pau Monne
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