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f6e8c47439
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
121 lines
3.1 KiB
C
121 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* Vhost-user protocol */
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#ifndef __VHOST_USER_H__
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#define __VHOST_USER_H__
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/* Message flags */
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#define VHOST_USER_FLAG_REPLY BIT(2)
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#define VHOST_USER_FLAG_NEED_REPLY BIT(3)
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/* Feature bits */
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#define VHOST_USER_F_PROTOCOL_FEATURES 30
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/* Protocol feature bits */
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#define VHOST_USER_PROTOCOL_F_REPLY_ACK 3
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#define VHOST_USER_PROTOCOL_F_SLAVE_REQ 5
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#define VHOST_USER_PROTOCOL_F_CONFIG 9
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#define VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS 14
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/* Vring state index masks */
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#define VHOST_USER_VRING_INDEX_MASK 0xff
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#define VHOST_USER_VRING_POLL_MASK BIT(8)
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/* Supported version */
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#define VHOST_USER_VERSION 1
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/* Supported transport features */
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#define VHOST_USER_SUPPORTED_F BIT_ULL(VHOST_USER_F_PROTOCOL_FEATURES)
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/* Supported protocol features */
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#define VHOST_USER_SUPPORTED_PROTOCOL_F (BIT_ULL(VHOST_USER_PROTOCOL_F_REPLY_ACK) | \
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BIT_ULL(VHOST_USER_PROTOCOL_F_SLAVE_REQ) | \
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BIT_ULL(VHOST_USER_PROTOCOL_F_CONFIG) | \
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BIT_ULL(VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS))
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enum vhost_user_request {
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VHOST_USER_GET_FEATURES = 1,
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VHOST_USER_SET_FEATURES = 2,
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VHOST_USER_SET_OWNER = 3,
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VHOST_USER_RESET_OWNER = 4,
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VHOST_USER_SET_MEM_TABLE = 5,
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VHOST_USER_SET_LOG_BASE = 6,
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VHOST_USER_SET_LOG_FD = 7,
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VHOST_USER_SET_VRING_NUM = 8,
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VHOST_USER_SET_VRING_ADDR = 9,
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VHOST_USER_SET_VRING_BASE = 10,
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VHOST_USER_GET_VRING_BASE = 11,
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VHOST_USER_SET_VRING_KICK = 12,
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VHOST_USER_SET_VRING_CALL = 13,
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VHOST_USER_SET_VRING_ERR = 14,
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VHOST_USER_GET_PROTOCOL_FEATURES = 15,
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VHOST_USER_SET_PROTOCOL_FEATURES = 16,
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VHOST_USER_GET_QUEUE_NUM = 17,
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VHOST_USER_SET_VRING_ENABLE = 18,
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VHOST_USER_SEND_RARP = 19,
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VHOST_USER_NET_SEND_MTU = 20,
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VHOST_USER_SET_SLAVE_REQ_FD = 21,
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VHOST_USER_IOTLB_MSG = 22,
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VHOST_USER_SET_VRING_ENDIAN = 23,
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VHOST_USER_GET_CONFIG = 24,
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VHOST_USER_SET_CONFIG = 25,
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VHOST_USER_VRING_KICK = 35,
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};
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enum vhost_user_slave_request {
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VHOST_USER_SLAVE_IOTLB_MSG = 1,
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VHOST_USER_SLAVE_CONFIG_CHANGE_MSG = 2,
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VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG = 3,
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VHOST_USER_SLAVE_VRING_CALL = 4,
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};
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struct vhost_user_header {
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/*
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* Use enum vhost_user_request for outgoing messages,
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* uses enum vhost_user_slave_request for incoming ones.
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*/
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u32 request;
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u32 flags;
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u32 size;
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} __packed;
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struct vhost_user_config {
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u32 offset;
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u32 size;
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u32 flags;
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u8 payload[]; /* Variable length */
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} __packed;
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struct vhost_user_vring_state {
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u32 index;
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u32 num;
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} __packed;
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struct vhost_user_vring_addr {
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u32 index;
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u32 flags;
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u64 desc, used, avail, log;
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} __packed;
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struct vhost_user_mem_region {
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u64 guest_addr;
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u64 size;
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u64 user_addr;
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u64 mmap_offset;
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} __packed;
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struct vhost_user_mem_regions {
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u32 num;
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u32 padding;
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struct vhost_user_mem_region regions[2]; /* Currently supporting 2 */
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} __packed;
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union vhost_user_payload {
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u64 integer;
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struct vhost_user_config config;
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struct vhost_user_vring_state vring_state;
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struct vhost_user_vring_addr vring_addr;
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struct vhost_user_mem_regions mem_regions;
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};
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struct vhost_user_msg {
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struct vhost_user_header header;
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union vhost_user_payload payload;
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} __packed;
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#endif
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