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From: Gleb Natapov <gleb@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Avi Kivity <avi@redhat.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Alex Williamson <alex.williamson@redhat.com>
Subject: Re: [PATCH] kvm: don't clear level from irqfd
Date: Wed, 27 Jun 2012 13:03:46 +0300	[thread overview]
Message-ID: <20120627100345.GA6533@redhat.com> (raw)
In-Reply-To: <20120627091343.GA17693@redhat.com>

On Wed, Jun 27, 2012 at 12:13:43PM +0300, Michael S. Tsirkin wrote:
> irqfd sets and clears the level immediately.
> This used to be necessary for MSI interrupts but isn't anymore.
> 
> Note! We never officially supported irqfd for level
> interrupts but it usually seemed to kind of work,
> and this change will break it. There are no known
> real users of that feature though - only old vfio prototypes.
> Removing this line will make it easier to add
> real support for level irqfds in the future.
> 
Did we officially supported irqfd for ioapic/pic edge interrupts?
Because those will break to.

> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  virt/kvm/eventfd.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
> index f59c1e8..4db6b01 100644
> --- a/virt/kvm/eventfd.c
> +++ b/virt/kvm/eventfd.c
> @@ -68,7 +68,6 @@ irqfd_inject(struct work_struct *work)
>  	struct kvm *kvm = irqfd->kvm;
>  
>  	kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1);
> -	kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0);
>  }
>  
>  /*
> -- 
> MST

--
			Gleb.

  reply	other threads:[~2012-06-27 10:03 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-27  9:13 [PATCH] kvm: don't clear level from irqfd Michael S. Tsirkin
2012-06-27 10:03 ` Gleb Natapov [this message]
2012-06-27 10:20   ` Michael S. Tsirkin
2012-06-27 10:22     ` Gleb Natapov
2012-06-27 11:38       ` Michael S. Tsirkin
2012-06-27 11:50         ` Gleb Natapov
2012-06-27 14:41         ` Alex Williamson
2012-06-27 15:00           ` Michael S. Tsirkin
2012-06-27 15:03             ` Gleb Natapov

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