From: Avi Kivity <avi@redhat.com>
To: Gregory Haskins <ghaskins@novell.com>
Cc: linux-kernel@vger.kernel.org, agraf@suse.de,
pmullaney@novell.com, pmorreale@novell.com,
anthony@codemonkey.ws, rusty@rustcorp.com.au,
netdev@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [RFC PATCH 01/17] shm-signal: shared-memory signals
Date: Tue, 31 Mar 2009 23:44:48 +0300 [thread overview]
Message-ID: <49D280C0.8010802@redhat.com> (raw)
In-Reply-To: <20090331184252.28333.70623.stgit@dev.haskins.net>
Gregory Haskins wrote:
> This interface provides a bidirectional shared-memory based signaling
> mechanism. It can be used by any entities which desire efficient
> communication via shared memory. The implementation details of the
> signaling are abstracted so that they may transcend a wide variety
> of locale boundaries (e.g. userspace/kernel, guest/host, etc).
>
> The shm_signal mechanism supports event masking as well as spurious
> event delivery mitigation.
> +
> +/*
> + *---------
> + * The following structures represent data that is shared across boundaries
> + * which may be quite disparate from one another (e.g. Windows vs Linux,
> + * 32 vs 64 bit, etc). Therefore, care has been taken to make sure they
> + * present data in a manner that is independent of the environment.
> + *-----------
> + */
> +
> +#define SHM_SIGNAL_MAGIC 0x58fa39df
> +#define SHM_SIGNAL_VER 1
> +
> +struct shm_signal_irq {
> + __u8 enabled;
> + __u8 pending;
> + __u8 dirty;
> +};
>
Some ABIs may choose to pad this, suggest explicit padding.
> +
> +enum shm_signal_locality {
> + shm_locality_north,
> + shm_locality_south,
> +};
> +
> +struct shm_signal_desc {
> + __u32 magic;
> + __u32 ver;
> + struct shm_signal_irq irq[2];
> +};
>
Similarly, this should be padded to 0 (mod 8).
Instead of versions, I prefer feature flags which can be independently
enabled or disabled.
> +
> +/* --- END SHARED STRUCTURES --- */
> +
> +#ifdef __KERNEL__
> +
> +#include <linux/interrupt.h>
> +
> +struct shm_signal_notifier {
> + void (*signal)(struct shm_signal_notifier *);
> +};
>
This means "->inject() has been called from the other side"?
(reading below I see this is so. not used to reading well commented
code... :)
> +
> +struct shm_signal;
> +
> +struct shm_signal_ops {
> + int (*inject)(struct shm_signal *s);
> + void (*fault)(struct shm_signal *s, const char *fmt, ...);
>
Eww. Must we involve strings and printf formats?
> + void (*release)(struct shm_signal *s);
> +};
> +
> +/*
> + * signaling protocol:
> + *
> + * each side of the shm_signal has an "irq" structure with the following
> + * fields:
> + *
> + * - enabled: controlled by shm_signal_enable/disable() to mask/unmask
> + * the notification locally
> + * - dirty: indicates if the shared-memory is dirty or clean. This
> + * is updated regardless of the enabled/pending state so that
> + * the state is always accurately tracked.
> + * - pending: indicates if a signal is pending to the remote locale.
> + * This allows us to determine if a remote-notification is
> + * already in flight to optimize spurious notifications away.
> + */
>
When you overlay a ring on top of this, won't the ring indexes convey
the same information as ->dirty?
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2009-03-31 20:44 UTC|newest]
Thread overview: 146+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-31 18:42 [RFC PATCH 00/17] virtual-bus Gregory Haskins
2009-03-31 18:42 ` [RFC PATCH 01/17] shm-signal: shared-memory signals Gregory Haskins
2009-03-31 20:44 ` Avi Kivity [this message]
2009-03-31 20:58 ` Gregory Haskins
2009-03-31 21:05 ` Avi Kivity
2009-04-01 12:12 ` Gregory Haskins
2009-04-01 12:24 ` Avi Kivity
2009-04-01 13:57 ` Gregory Haskins
2009-03-31 18:42 ` [RFC PATCH 02/17] vbus: add virtual-bus definitions Gregory Haskins
2009-04-02 16:06 ` Ben Hutchings
2009-04-02 18:13 ` Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 03/17] vbus: add connection-client helper infrastructure Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 04/17] vbus: add bus-registration notifiers Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 05/17] vbus: add a "vbus-proxy" bus model for vbus_driver objects Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 06/17] ioq: Add basic definitions for a shared-memory, lockless queue Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 07/17] ioq: add vbus helpers Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 08/17] venet: add the ABI definitions for an 802.x packet interface Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 09/17] net: Add vbus_enet driver Gregory Haskins
2009-03-31 20:39 ` Stephen Hemminger
2009-04-02 11:43 ` Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 10/17] venet-tap: Adds a "venet" compatible "tap" device to VBUS Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 11/17] venet: add scatter-gather support Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 12/17] venettap: " Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 13/17] x86: allow the irq->vector translation to be determined outside of ioapic Gregory Haskins
2009-03-31 19:16 ` Alan Cox
2009-03-31 20:02 ` Gregory Haskins
2009-03-31 18:44 ` [RFC PATCH 14/17] kvm: add a reset capability Gregory Haskins
2009-03-31 19:22 ` Avi Kivity
2009-03-31 20:02 ` Gregory Haskins
2009-03-31 20:18 ` Avi Kivity
2009-03-31 20:37 ` Gregory Haskins
2009-03-31 18:44 ` [RFC PATCH 15/17] kvm: add dynamic IRQ support Gregory Haskins
2009-03-31 19:20 ` Avi Kivity
2009-03-31 19:39 ` Gregory Haskins
2009-03-31 20:13 ` Avi Kivity
2009-03-31 20:32 ` Gregory Haskins
2009-03-31 20:59 ` Avi Kivity
2009-03-31 18:44 ` [RFC PATCH 16/17] kvm: Add VBUS support to the host Gregory Haskins
2009-03-31 18:44 ` [RFC PATCH 17/17] kvm: Add guest-side support for VBUS Gregory Haskins
2009-03-31 20:18 ` [RFC PATCH 00/17] virtual-bus Andi Kleen
2009-04-01 12:03 ` Gregory Haskins
2009-04-01 13:23 ` Andi Kleen
2009-04-01 14:19 ` Gregory Haskins
2009-04-01 14:42 ` Gregory Haskins
2009-04-01 17:01 ` Andi Kleen
2009-04-01 18:45 ` Anthony Liguori
2009-04-01 20:40 ` Chris Wright
2009-04-01 21:11 ` Gregory Haskins
2009-04-01 21:28 ` Chris Wright
2009-04-01 22:10 ` Gregory Haskins
2009-04-02 6:00 ` Chris Wright
2009-04-02 3:11 ` Herbert Xu
2009-04-01 21:09 ` Gregory Haskins
2009-04-02 0:29 ` Anthony Liguori
2009-04-02 3:11 ` Gregory Haskins
2009-04-02 6:51 ` Avi Kivity
2009-04-02 8:52 ` Herbert Xu
2009-04-02 9:02 ` Avi Kivity
2009-04-02 9:16 ` Herbert Xu
2009-04-02 9:27 ` Avi Kivity
2009-04-02 9:29 ` Herbert Xu
2009-04-02 9:33 ` Herbert Xu
2009-04-02 9:38 ` Avi Kivity
2009-04-02 9:41 ` Herbert Xu
2009-04-02 9:43 ` Avi Kivity
2009-04-02 9:44 ` Herbert Xu
2009-04-02 11:06 ` Gregory Haskins
2009-04-02 11:59 ` Avi Kivity
2009-04-02 12:30 ` Gregory Haskins
2009-04-02 12:43 ` Avi Kivity
2009-04-02 13:03 ` Gregory Haskins
2009-04-02 12:13 ` Rusty Russell
2009-04-02 12:50 ` Gregory Haskins
2009-04-02 12:52 ` Gregory Haskins
2009-04-02 13:07 ` Avi Kivity
2009-04-02 13:22 ` Gregory Haskins
2009-04-02 13:27 ` Avi Kivity
2009-04-02 14:05 ` Gregory Haskins
2009-04-02 14:50 ` Herbert Xu
2009-04-02 15:00 ` Avi Kivity
2009-04-02 15:40 ` Herbert Xu
2009-04-02 15:57 ` Avi Kivity
2009-04-02 16:09 ` Herbert Xu
2009-04-02 16:54 ` Avi Kivity
2009-04-02 17:06 ` Herbert Xu
2009-04-02 17:17 ` Herbert Xu
2009-04-03 12:25 ` Avi Kivity
2009-04-02 15:10 ` Michael S. Tsirkin
2009-04-03 4:43 ` Jeremy Fitzhardinge
2009-04-02 10:55 ` Gregory Haskins
2009-04-02 11:48 ` Avi Kivity
2009-04-03 10:58 ` Gerd Hoffmann
2009-04-03 11:03 ` Avi Kivity
2009-04-03 11:12 ` Herbert Xu
2009-04-03 11:46 ` Avi Kivity
2009-04-03 11:48 ` Herbert Xu
2009-04-03 11:54 ` Avi Kivity
2009-04-03 11:55 ` Herbert Xu
2009-04-03 12:02 ` Avi Kivity
2009-04-03 13:05 ` Herbert Xu
2009-04-03 11:18 ` Andi Kleen
2009-04-03 11:34 ` Herbert Xu
2009-04-03 11:46 ` Avi Kivity
2009-04-03 11:28 ` Gregory Haskins
2009-04-02 10:46 ` Gregory Haskins
2009-04-02 11:43 ` Avi Kivity
2009-04-02 12:22 ` Gregory Haskins
2009-04-02 12:42 ` Avi Kivity
2009-04-02 12:54 ` Gregory Haskins
2009-04-02 13:08 ` Avi Kivity
2009-04-02 13:36 ` Gregory Haskins
2009-04-02 13:45 ` Avi Kivity
2009-04-02 14:24 ` Gregory Haskins
2009-04-02 14:32 ` Avi Kivity
2009-04-02 14:41 ` Avi Kivity
2009-04-02 14:49 ` Anthony Liguori
2009-04-02 16:09 ` Anthony Liguori
2009-04-02 16:19 ` Avi Kivity
2009-04-02 18:18 ` Anthony Liguori
2009-04-03 1:11 ` Herbert Xu
2009-04-20 18:02 ` Alex Williamson
2009-04-03 12:03 ` Gregory Haskins
2009-04-03 12:15 ` Avi Kivity
2009-04-03 13:13 ` Gregory Haskins
2009-04-03 13:37 ` Avi Kivity
2009-04-03 16:28 ` Gregory Haskins
2009-04-05 10:00 ` Avi Kivity
2009-04-02 3:09 ` Herbert Xu
2009-04-02 6:46 ` Avi Kivity
2009-04-02 8:54 ` Herbert Xu
2009-04-02 9:03 ` Avi Kivity
2009-04-02 9:05 ` Herbert Xu
2009-04-01 20:29 ` Gregory Haskins
2009-04-01 22:23 ` Andi Kleen
2009-04-01 23:05 ` Gregory Haskins
2009-04-01 6:08 ` Rusty Russell
2009-04-01 11:35 ` Gregory Haskins
2009-04-02 1:24 ` Rusty Russell
2009-04-02 2:27 ` Gregory Haskins
2009-04-01 16:10 ` Anthony Liguori
2009-04-05 3:44 ` Rusty Russell
2009-04-05 8:06 ` Avi Kivity
2009-04-05 14:13 ` Anthony Liguori
2009-04-05 16:10 ` Avi Kivity
2009-04-05 16:45 ` Anthony Liguori
2009-04-02 3:15 ` Herbert Xu
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