/******************************************************************************
* evtchn.h
*
* Interface to /dev/xen/evtchn.
*
* Copyright (c) 2003-2005, K A Fraser
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation; or, when distributed
* separately from the Linux kernel or incorporated into other
* software packages, subject to the following license:
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this source file (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy, modify,
* merge, publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#ifndef __LINUX_PUBLIC_EVTCHN_H__
#define __LINUX_PUBLIC_EVTCHN_H__
/*
* Bind a fresh port to VIRQ @virq.
* Return allocated port.
*/
#define IOCTL_EVTCHN_BIND_VIRQ \
_IOC(_IOC_NONE, 'E', 0, sizeof(struct ioctl_evtchn_bind_virq))
struct ioctl_evtchn_bind_virq {
unsigned int virq;
};
/*
* Bind a fresh port to remote <@remote_domain, @remote_port>.
* Return allocated port.
*/
#define IOCTL_EVTCHN_BIND_INTERDOMAIN \
_IOC(_IOC_NONE, 'E', 1, sizeof(struct ioctl_evtchn_bind_interdomain))
struct ioctl_evtchn_bind_interdomain {
unsigned int remote_domain, remote_port;
};
/*
* Allocate a fresh port for binding to @remote_domain.
* Return allocated port.
*/
#define IOCTL_EVTCHN_BIND_UNBOUND_PORT \
_IOC(_IOC_NONE, 'E', 2, sizeof(struct ioctl_evtchn_bind_unbound_port))
struct ioctl_evtchn_bind_unbound_port {
unsigned int remote_domain;
};
/*
* Unbind previously allocated @port.
*/
#define IOCTL_EVTCHN_UNBIND \
_IOC(_IOC_NONE, 'E', 3, sizeof(struct ioctl_evtchn_unbind))
struct ioctl_evtchn_unbind {
unsigned int port;
};
/*
* Unbind previously allocated @port.
*/
#define IOCTL_EVTCHN_NOTIFY \
_IOC(_IOC_NONE, 'E', 4, sizeof(struct ioctl_evtchn_notify))
struct ioctl_evtchn_notify {
unsigned int port;
};
/* Clear and reinitialise the event buffer. Clear error condition. */
#define IOCTL_EVTCHN_RESET \
_IOC(_IOC_NONE, 'E', 5, 0)
/*
* Restrict this file descriptor so that it can only be used to bind
* new interdomain events from one domain.
*
* Once a file descriptor has been restricted it cannot be
* de-restricted, and must be closed and re-opened. Event channels
* which were bound before restricting remain bound afterwards, and
* can be notified as usual.
*/
#define IOCTL_EVTCHN_RESTRICT_DOMID \
_IOC(_IOC_NONE, 'E', 6, sizeof(struct ioctl_evtchn_restrict_domid))
struct ioctl_evtchn_restrict_domid {
domid_t domid;
};
#endif /* __LINUX_PUBLIC_EVTCHN_H__ */
ion>
Commit a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")
added the proper mb(), but removed the test "prev_write_sz < pending_sz"
when making the signal decision.
As a result, the guest can signal the host unnecessarily,
and then the host can throttle the guest because the host
thinks the guest is buggy or malicious; finally the user
running stress test can perceive intermittent freeze of
the guest.
This patch brings back the test, and properly handles the
in-place consumption APIs used by NetVSC (see get_next_pkt_raw(),
put_pkt_raw() and commit_rd_index()).
Fixes: a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reported-by: Rolf Neugebauer <rolf.neugebauer@docker.com>
Tested-by: Rolf Neugebauer <rolf.neugebauer@docker.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>