forked from Minki/linux
f42a0fd13b
This change restricts the reading and setting of the head and tail pointers on 32bit X86 to 32bit for both correctness and performance reasons. On uniprocessor X86_32, the atomic64_read may be implemented as a non-locked cmpxchg8b. This may result in updates to the pointers done by the VMCI device being overwritten. On MP systems, there is no such correctness issue, but using 32bit atomics avoids the overhead of the locked 64bit operation. All this is safe because the queue size on 32bit systems will never exceed a 32bit value. Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> Signed-off-by: Jorgen Hansen <jhansen@vmware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
118 lines
3.0 KiB
C
118 lines
3.0 KiB
C
/*
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* VMware VMCI Driver
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*
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* Copyright (C) 2012 VMware, Inc. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation version 2 and no later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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#include <linux/vmw_vmci_defs.h>
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#include <linux/vmw_vmci_api.h>
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#include <linux/atomic.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include "vmci_driver.h"
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#include "vmci_event.h"
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static bool vmci_disable_host;
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module_param_named(disable_host, vmci_disable_host, bool, 0);
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MODULE_PARM_DESC(disable_host,
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"Disable driver host personality (default=enabled)");
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static bool vmci_disable_guest;
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module_param_named(disable_guest, vmci_disable_guest, bool, 0);
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MODULE_PARM_DESC(disable_guest,
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"Disable driver guest personality (default=enabled)");
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static bool vmci_guest_personality_initialized;
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static bool vmci_host_personality_initialized;
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/*
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* vmci_get_context_id() - Gets the current context ID.
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*
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* Returns the current context ID. Note that since this is accessed only
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* from code running in the host, this always returns the host context ID.
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*/
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u32 vmci_get_context_id(void)
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{
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if (vmci_guest_code_active())
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return vmci_get_vm_context_id();
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else if (vmci_host_code_active())
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return VMCI_HOST_CONTEXT_ID;
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return VMCI_INVALID_ID;
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}
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EXPORT_SYMBOL_GPL(vmci_get_context_id);
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static int __init vmci_drv_init(void)
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{
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int vmci_err;
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int error;
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vmci_err = vmci_event_init();
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if (vmci_err < VMCI_SUCCESS) {
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pr_err("Failed to initialize VMCIEvent (result=%d)\n",
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vmci_err);
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return -EINVAL;
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}
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if (!vmci_disable_guest) {
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error = vmci_guest_init();
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if (error) {
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pr_warn("Failed to initialize guest personality (err=%d)\n",
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error);
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} else {
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vmci_guest_personality_initialized = true;
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pr_info("Guest personality initialized and is %s\n",
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vmci_guest_code_active() ?
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"active" : "inactive");
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}
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}
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if (!vmci_disable_host) {
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error = vmci_host_init();
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if (error) {
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pr_warn("Unable to initialize host personality (err=%d)\n",
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error);
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} else {
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vmci_host_personality_initialized = true;
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pr_info("Initialized host personality\n");
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}
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}
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if (!vmci_guest_personality_initialized &&
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!vmci_host_personality_initialized) {
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vmci_event_exit();
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return -ENODEV;
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}
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return 0;
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}
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module_init(vmci_drv_init);
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static void __exit vmci_drv_exit(void)
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{
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if (vmci_guest_personality_initialized)
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vmci_guest_exit();
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if (vmci_host_personality_initialized)
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vmci_host_exit();
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vmci_event_exit();
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}
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module_exit(vmci_drv_exit);
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MODULE_AUTHOR("VMware, Inc.");
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MODULE_DESCRIPTION("VMware Virtual Machine Communication Interface.");
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MODULE_VERSION("1.1.4.0-k");
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MODULE_LICENSE("GPL v2");
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