forked from Minki/linux
1d897e478d
Rather than allocating/freeing a piece of memory every time
we try to figure out how long a CCW chain is, let's use a piece
of memory allocated for each device.
The io_mutex added with commit 4f76617378 ("vfio-ccw: protect
the I/O region") is held for the duration of the VFIO_CCW_EVENT_IO_REQ
event that accesses/uses this space, so there should be no race
concerns with another CPU attempting an (unexpected) SSCH for the
same device.
Suggested-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Message-Id: <20190618202352.39702-2-farman@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
53 lines
1.5 KiB
C
53 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* channel program interfaces
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*
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* Copyright IBM Corp. 2017
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*
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* Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
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* Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
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*/
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#ifndef _VFIO_CCW_CP_H_
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#define _VFIO_CCW_CP_H_
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#include <asm/cio.h>
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#include <asm/scsw.h>
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#include "orb.h"
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/*
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* Max length for ccw chain.
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* XXX: Limit to 256, need to check more?
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*/
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#define CCWCHAIN_LEN_MAX 256
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/**
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* struct channel_program - manage information for channel program
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* @ccwchain_list: list head of ccwchains
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* @orb: orb for the currently processed ssch request
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* @mdev: the mediated device to perform page pinning/unpinning
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* @initialized: whether this instance is actually initialized
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*
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* @ccwchain_list is the head of a ccwchain list, that contents the
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* translated result of the guest channel program that pointed out by
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* the iova parameter when calling cp_init.
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*/
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struct channel_program {
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struct list_head ccwchain_list;
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union orb orb;
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struct device *mdev;
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bool initialized;
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struct ccw1 *guest_cp;
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};
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extern int cp_init(struct channel_program *cp, struct device *mdev,
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union orb *orb);
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extern void cp_free(struct channel_program *cp);
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extern int cp_prefetch(struct channel_program *cp);
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extern union orb *cp_get_orb(struct channel_program *cp, u32 intparm, u8 lpm);
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extern void cp_update_scsw(struct channel_program *cp, union scsw *scsw);
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extern bool cp_iova_pinned(struct channel_program *cp, u64 iova);
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#endif
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