From: Joerg Roedel <joro@8bytes.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
tglx@linutronix.de
Subject: Re: [PATCH 05/10] iommu/amd: remove the special case from get_irq_table()
Date: Thu, 15 Mar 2018 16:19:17 +0100 [thread overview]
Message-ID: <20180315151917.pgheszruqnnjbqb4@8bytes.org> (raw)
In-Reply-To: <20180315141541.6g3xc6yi4siafuwr@linutronix.de>
On Thu, Mar 15, 2018 at 03:15:41PM +0100, Sebastian Andrzej Siewior wrote:
> ->set_allocated() operates only on 0…31 and other could be used at the
> same time. However 0…31 should be accessed by other user before they are
> ready.
>
> irq_remapping_alloc() is that ->alloc() callback invoked via
> irq_domain_alloc_irqs_hierarchy() and each caller has to hold the
> &irq_domain_mutex mutex. So we should not have those in parallel.
>
> Is it possible to have those entries accessed before the setup is
> complete? My understanding is that this setup is performed once during
> boot (especially that ioapic part) and not again.
>
> From looking at that hunk, it should not hurt to add that lock, just
> wanted to check it is really needed.
Okay, if the irq-layer does the needed locking, then we don't need
another lock here. There is the modify_irte_ga() path for the
virtualized irq routing into KVM guests, but there should be no KVM
guests running when setup the ioapic routing entries.
Joerg
next prev parent reply other threads:[~2018-03-15 15:19 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-23 22:27 iommu/amd: lock splitting & GFP_KERNEL allocation Sebastian Andrzej Siewior
2018-02-23 22:27 ` [PATCH 01/10] iommu/amd: take into account that alloc_dev_data() may return NULL Sebastian Andrzej Siewior
2018-02-23 22:27 ` [PATCH 02/10] iommu/amd: turn dev_data_list into a lock less list Sebastian Andrzej Siewior
2018-02-23 22:27 ` [PATCH 03/10] iommu/amd: split domain id out of amd_iommu_devtable_lock Sebastian Andrzej Siewior
2018-02-23 22:27 ` [PATCH 04/10] iommu/amd: split irq_lookup_table out of the amd_iommu_devtable_lock Sebastian Andrzej Siewior
2018-03-15 12:54 ` Joerg Roedel
2018-02-23 22:27 ` [PATCH 05/10] iommu/amd: remove the special case from get_irq_table() Sebastian Andrzej Siewior
2018-03-15 12:53 ` Joerg Roedel
2018-03-15 13:01 ` Sebastian Andrzej Siewior
2018-03-15 13:07 ` Joerg Roedel
2018-03-15 14:15 ` Sebastian Andrzej Siewior
2018-03-15 15:19 ` Joerg Roedel [this message]
2018-03-15 15:25 ` Sebastian Andrzej Siewior
2018-02-23 22:27 ` [PATCH 06/10] iommu/amd: use `table' instead `irt' as variable name in amd_iommu_update_ga() Sebastian Andrzej Siewior
2018-02-23 22:27 ` [PATCH 07/10] iommu/amd: factor out setting the remap table for a devid Sebastian Andrzej Siewior
2018-02-23 22:27 ` [PATCH 08/10] iommu/amd: drop the lock while allocating new irq remap table Sebastian Andrzej Siewior
2018-03-15 12:58 ` Joerg Roedel
2018-02-23 22:27 ` [PATCH 09/10] iommu/amd: declare irq_remap_table's and amd_iommu's lock as a raw_spin_lock Sebastian Andrzej Siewior
2018-02-23 22:27 ` [PATCH 10/10] iommu/amd: make amd_iommu_devtable_lock a spin_lock Sebastian Andrzej Siewior
2018-03-15 13:01 ` iommu/amd: lock splitting & GFP_KERNEL allocation Joerg Roedel
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=20180315151917.pgheszruqnnjbqb4@8bytes.org \
--to=joro@8bytes.org \
--cc=bigeasy@linutronix.de \
--cc=iommu@lists.linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=tglx@linutronix.de \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®