153 lines
3.4 KiB
C
153 lines
3.4 KiB
C
/*
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* Copyright (C) 2022 Intel Corporation.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include "ivshmemlib.h"
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//The shared memory region that is used for inter-vm shared memory
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char *ivshmem_ptr = NULL;
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/*
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int setup_ivshmem_region(const char *f_path)
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input: char *f_path - A string containing the pci resource2 filepath
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output: int - Whether the setup succeeded or not
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This function attempts to open the file whose path is f_path
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On success it returns 0
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On failure it returns -1
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*/
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int setup_ivshmem_region(const char *f_path)
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{
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//Open the file so we can map it into memory
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int pci_file = open(f_path, O_RDWR | O_SYNC);
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if (pci_file == failure) {
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perror("Failed to open the resource2 file\n");
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return failure;
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}
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//Map the file into memory
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ivshmem_ptr = (char *)mmap(0, REGION_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, pci_file , 0);
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close(pci_file);
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if (!ivshmem_ptr) {
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perror("Failed to map the shared memory region into our address space\n");
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return failure;
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}
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return success;
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}
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/*
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int close_ivshmem_region(void)
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output: int - Whether unmapping the region succeeded or not.
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This function closes the ivshmem region
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On success it returns 0
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On failure it returns -1
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*/
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int close_ivshmem_region(void)
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{
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int ret_val = failure;
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//Determine if ivshmem region is set up
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if (ivshmem_ptr) {
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ret_val = munmap(ivshmem_ptr, REGION_SIZE);
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ivshmem_ptr = NULL;
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}
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else
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printf("Ivshmem region is not set up.");
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return ret_val;
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}
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/*
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size_t read_ivshmem_region(char *ivshmemPtr, char *user_ptr, size_t size)
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input: char *user_ptr - The memory to write to
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input: size_t size - the number of bytes to read from the memory
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output: size_t - The number of bytes that were successfully read or -1 on failure
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This function reads from the ivshmem region and copies size - 1 bytes
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from the shared memory region to the user_ptr
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and null-terminates the string
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*/
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size_t read_ivshmem_region(char *user_ptr, size_t size)
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{
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//Number of bytes copied
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size_t ret = failure;
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//Make sure that we actually need to read something
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if (size == 0)
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return ret;
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//Determine if ivshmem region is set up
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if ((ivshmem_ptr) && (size < REGION_SIZE - 1)) {
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//Do the copy and zero out the ivshmem region
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bzero(user_ptr, size);
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strncpy(user_ptr, ivshmem_ptr, size);
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ivshmem_ptr[size] = '\0';
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user_ptr[size] = '\0';
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ret = strlen(user_ptr);
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bzero(ivshmem_ptr, size);
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}
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else
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printf("Ivshmem region is not set up.");
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return ret;
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}
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/*
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size_t write_ivshmem_region(char *ivshmemPtr, char *user_ptr, size_t size)
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input: char *user_ptr - The memory to read from
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input: int size - the number of bytes to write from the memory
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output: int - The number of bytes that were successfully written or -1 on failure
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This function reads from the user_ptr and copies size - 1 bytes
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to the shared memory region
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and null-terminates the string
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*/
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size_t write_ivshmem_region(char *user_ptr, size_t size)
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{
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//Return value that holds the amount of bytes that were copied from the user_ptr
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size_t ret = failure;
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//Make sure that we need to actually write something
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if (size == 0)
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return ret;
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//Determine if ivshmem region is set up
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if ((ivshmem_ptr) && (size < REGION_SIZE - 1)) {
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//Do the copy and zero out the user_ptr
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bzero(ivshmem_ptr, size);
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strncpy(ivshmem_ptr, user_ptr, size);
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user_ptr[size] = '\0';
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ivshmem_ptr[size] = '\0';
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ret = strlen(ivshmem_ptr);
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bzero(user_ptr, size);
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}
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else
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printf("Ivshmem region is not set up.");
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return ret;
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}
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