linux/tools/hv/vmbus_bufring.h
Saurabh Sengar 45bab4d746 tools: hv: Add vmbus_bufring
Common userspace interface for read/write from VMBus ringbuffer.
This implementation is open for use by any userspace driver or
application seeking direct control over VMBus ring buffers.
A significant  part of this code is borrowed from DPDK.
Link: https://github.com/DPDK/dpdk/

Currently this library is not supported for ARM64.

Signed-off-by: Mary Hardy <maryhardy@microsoft.com>
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Long Li <longli@microsoft.com>
Link: https://lore.kernel.org/r/1711788723-8593-5-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-04-11 14:55:53 +02:00

159 lines
4.1 KiB
C

/* SPDX-License-Identifier: BSD-3-Clause */
#ifndef _VMBUS_BUF_H_
#define _VMBUS_BUF_H_
#include <stdbool.h>
#include <stdint.h>
#define __packed __attribute__((__packed__))
#define unlikely(x) __builtin_expect(!!(x), 0)
#define ICMSGHDRFLAG_TRANSACTION 1
#define ICMSGHDRFLAG_REQUEST 2
#define ICMSGHDRFLAG_RESPONSE 4
#define IC_VERSION_NEGOTIATION_MAX_VER_COUNT 100
#define ICMSG_HDR (sizeof(struct vmbuspipe_hdr) + sizeof(struct icmsg_hdr))
#define ICMSG_NEGOTIATE_PKT_SIZE(icframe_vercnt, icmsg_vercnt) \
(ICMSG_HDR + sizeof(struct icmsg_negotiate) + \
(((icframe_vercnt) + (icmsg_vercnt)) * sizeof(struct ic_version)))
/*
* Channel packets
*/
/* Channel packet flags */
#define VMBUS_CHANPKT_TYPE_INBAND 0x0006
#define VMBUS_CHANPKT_TYPE_RXBUF 0x0007
#define VMBUS_CHANPKT_TYPE_GPA 0x0009
#define VMBUS_CHANPKT_TYPE_COMP 0x000b
#define VMBUS_CHANPKT_FLAG_NONE 0
#define VMBUS_CHANPKT_FLAG_RC 0x0001 /* report completion */
#define VMBUS_CHANPKT_SIZE_SHIFT 3
#define VMBUS_CHANPKT_SIZE_ALIGN BIT(VMBUS_CHANPKT_SIZE_SHIFT)
#define VMBUS_CHANPKT_HLEN_MIN \
(sizeof(struct vmbus_chanpkt_hdr) >> VMBUS_CHANPKT_SIZE_SHIFT)
/*
* Buffer ring
*/
struct vmbus_bufring {
volatile uint32_t windex;
volatile uint32_t rindex;
/*
* Interrupt mask {0,1}
*
* For TX bufring, host set this to 1, when it is processing
* the TX bufring, so that we can safely skip the TX event
* notification to host.
*
* For RX bufring, once this is set to 1 by us, host will not
* further dispatch interrupts to us, even if there are data
* pending on the RX bufring. This effectively disables the
* interrupt of the channel to which this RX bufring is attached.
*/
volatile uint32_t imask;
/*
* Win8 uses some of the reserved bits to implement
* interrupt driven flow management. On the send side
* we can request that the receiver interrupt the sender
* when the ring transitions from being full to being able
* to handle a message of size "pending_send_sz".
*
* Add necessary state for this enhancement.
*/
volatile uint32_t pending_send;
uint32_t reserved1[12];
union {
struct {
uint32_t feat_pending_send_sz:1;
};
uint32_t value;
} feature_bits;
/* Pad it to rte_mem_page_size() so that data starts on page boundary */
uint8_t reserved2[4028];
/*
* Ring data starts here + RingDataStartOffset
* !!! DO NOT place any fields below this !!!
*/
uint8_t data[];
} __packed;
struct vmbus_br {
struct vmbus_bufring *vbr;
uint32_t dsize;
uint32_t windex; /* next available location */
};
struct vmbus_chanpkt_hdr {
uint16_t type; /* VMBUS_CHANPKT_TYPE_ */
uint16_t hlen; /* header len, in 8 bytes */
uint16_t tlen; /* total len, in 8 bytes */
uint16_t flags; /* VMBUS_CHANPKT_FLAG_ */
uint64_t xactid;
} __packed;
struct vmbus_chanpkt {
struct vmbus_chanpkt_hdr hdr;
} __packed;
struct vmbuspipe_hdr {
unsigned int flags;
unsigned int msgsize;
} __packed;
struct ic_version {
unsigned short major;
unsigned short minor;
} __packed;
struct icmsg_negotiate {
unsigned short icframe_vercnt;
unsigned short icmsg_vercnt;
unsigned int reserved;
struct ic_version icversion_data[]; /* any size array */
} __packed;
struct icmsg_hdr {
struct ic_version icverframe;
unsigned short icmsgtype;
struct ic_version icvermsg;
unsigned short icmsgsize;
unsigned int status;
unsigned char ictransaction_id;
unsigned char icflags;
unsigned char reserved[2];
} __packed;
int rte_vmbus_chan_recv_raw(struct vmbus_br *rxbr, void *data, uint32_t *len);
int rte_vmbus_chan_send(struct vmbus_br *txbr, uint16_t type, void *data,
uint32_t dlen, uint32_t flags);
void vmbus_br_setup(struct vmbus_br *br, void *buf, unsigned int blen);
void *vmbus_uio_map(int *fd, int size);
/* Amount of space available for write */
static inline uint32_t vmbus_br_availwrite(const struct vmbus_br *br, uint32_t windex)
{
uint32_t rindex = br->vbr->rindex;
if (windex >= rindex)
return br->dsize - (windex - rindex);
else
return rindex - windex;
}
static inline uint32_t vmbus_br_availread(const struct vmbus_br *br)
{
return br->dsize - vmbus_br_availwrite(br, br->vbr->windex);
}
#endif /* !_VMBUS_BUF_H_ */