From: Jan Beulich <jbeulich@suse.com>
To: Juergen Gross <jgross@suse.com>
Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
Stefano Stabellini <sstabellini@kernel.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [Xen-devel] [PATCH] xen/events: remove event handling recursion detection
Date: Mon, 4 Nov 2019 15:35:09 +0100 [thread overview]
Message-ID: <40cba9d9-24b0-3141-4ba8-02e03049f1bf@suse.com> (raw)
In-Reply-To: <20191104135812.2314-1-jgross@suse.com>
On 04.11.2019 14:58, Juergen Gross wrote:
> __xen_evtchn_do_upcall() contains guards against being called
> recursively. This mechanism was introduced in the early pvops times
> (kernel 2.6.26) when there were still Xen versions around not honoring
> disabled interrupts for sending events to pv guests.
>
> This was changed in Xen 3.0, which is much older than any Xen version
> supported by the kernel, so the recursion detection can be removed.
Would you mind pointing out which exact change(s) this was(were)?
It had always been my understanding that the recursion detection
was mainly to guard against drivers re-enabling interrupts
transiently in their handlers (which in turn may no longer be an
issue in modern Linux kernels).
Jan
next prev parent reply other threads:[~2019-11-04 14:35 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-04 13:58 Juergen Gross
2019-11-04 14:35 ` Jan Beulich [this message]
2019-11-04 15:09 ` [Xen-devel] " Jürgen Groß
2019-11-04 15:19 ` Jan Beulich
2019-11-04 16:18 ` Jürgen Groß
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