From: Alexander Popov <alex.popov@linux.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>,
LKML <linux-kernel@vger.kernel.org>,
Alexander Popov <alex.popov@linux.com>
Subject: Re: [PATCH 1/1] irqdomain: Export __irq_domain_alloc_irqs() and irq_domain_free_irqs()
Date: Fri, 8 Jul 2016 11:34:00 +0300 [thread overview]
Message-ID: <577F6578.6030904@linux.com> (raw)
In-Reply-To: <alpine.DEB.2.11.1607061316420.4083@nanos>
On 06.07.2016 14:17, Thomas Gleixner wrote:
> On Fri, 1 Jul 2016, Alexander Popov wrote:
>
>> Export __irq_domain_alloc_irqs() and irq_domain_free_irqs() for being
>> able to work with irq_domain hierarchy in modules.
>
> We usually export only when we have a proper use case which is supposed to go
> into the kernel tree proper. What's yours?
Hello, Thomas,
I work at Positive Technologies ( https://www.ptsecurity.com/ ). We develop
a bare-metal hypervisor, which targets x86_64 and supports Linux as a guest OS.
Intel VT-x allows hypervisor to inject interrupts into virtual machines.
We want to handle these interrupts in guest Linux.
So I wrote a simple kernel module creating an irq_domain, which has
x86_vector_domain as a parent in the hierarchy. In this module I just call:
- irq_domain_alloc_irqs() to allocate irqs and allow calling request_irq()
for them;
- irqd_cfg(irq_get_irq_data()) to get the APIC vectors of the allocated irqs;
- irq_domain_free_irqs() to free the resources at the end.
It allows to handle interrupts injected by the hypervisor in guest Linux easily,
without emulating MSI-capable PCI device at the hypervisor side.
Everything works fine if __irq_domain_alloc_irqs() and irq_domain_free_irqs()
are exported. Is it a proper use-case?
Do you think my module could be useful for the mainline in some form?
It took me some time to understand irq_domain hierarchy design, so I can
prepare some patch or share my code to help others.
Best regards,
Alexander
next prev parent reply other threads:[~2016-07-08 8:31 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-01 19:29 [PATCH 1/1] irqdomain: Export __irq_domain_alloc_irqs() and irq_domain_free_irqs() Alexander Popov
2016-07-06 11:17 ` Thomas Gleixner
2016-07-08 8:34 ` Alexander Popov [this message]
2016-07-16 1:33 ` Alexander Popov
2016-07-16 8:22 ` Marc Zyngier
2016-07-18 12:34 ` Alexander Popov
2016-07-25 19:35 ` Alexander Popov
2016-07-27 11:22 ` Christoph Hellwig
2016-07-29 23:21 ` Alexander Popov
2016-08-01 11:28 ` Jason Cooper
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