diff options
| -rw-r--r-- | arch/powerpc/platforms/pseries/papr-hvpipe.c | 164 | ||||
| -rw-r--r-- | arch/powerpc/platforms/pseries/papr-hvpipe.h | 1 |
2 files changed, 163 insertions, 2 deletions
diff --git a/arch/powerpc/platforms/pseries/papr-hvpipe.c b/arch/powerpc/platforms/pseries/papr-hvpipe.c index 9f2bac71bab1..87deb429b331 100644 --- a/arch/powerpc/platforms/pseries/papr-hvpipe.c +++ b/arch/powerpc/platforms/pseries/papr-hvpipe.c @@ -61,6 +61,54 @@ static LIST_HEAD(hvpipe_src_list); */ /* + * ibm,receive-hvpipe-msg RTAS call. + * @area: Caller-provided work area buffer for results. + * @srcID: Source ID returned by the RTAS call. + * @bytesw: Bytes written by RTAS call to @area. + */ +static int rtas_ibm_receive_hvpipe_msg(struct rtas_work_area *area, + u32 *srcID, u32 *bytesw) +{ + const s32 token = rtas_function_token(RTAS_FN_IBM_RECEIVE_HVPIPE_MSG); + u32 rets[2]; + s32 fwrc; + int ret; + + if (token == RTAS_UNKNOWN_SERVICE) + return -ENOENT; + + do { + fwrc = rtas_call(token, 2, 3, rets, + rtas_work_area_phys(area), + rtas_work_area_size(area)); + + } while (rtas_busy_delay(fwrc)); + + switch (fwrc) { + case RTAS_SUCCESS: + *srcID = rets[0]; + *bytesw = rets[1]; + ret = 0; + break; + case RTAS_HARDWARE_ERROR: + ret = -EIO; + break; + case RTAS_INVALID_PARAMETER: + ret = -EINVAL; + break; + case RTAS_FUNC_NOT_SUPPORTED: + ret = -EOPNOTSUPP; + break; + default: + ret = -EIO; + pr_err_ratelimited("unexpected ibm,receive-hvpipe-msg status %d\n", fwrc); + break; + } + + return ret; +} + +/* * ibm,send-hvpipe-msg RTAS call * @area: Caller-provided work area buffer to send. * @srcID: Target source for the send pipe message. @@ -117,8 +165,59 @@ static struct hvpipe_source_info *hvpipe_find_source(u32 srcID) } /* + * This work function collects receive buffer with recv HVPIPE + * RTAS call. Called from read() + * @buf: User specified buffer to copy the payload that returned + * from recv HVPIPE RTAS. + * @size: Size of buffer user passed. + */ +static int hvpipe_rtas_recv_msg(char __user *buf, int size) +{ + struct rtas_work_area *work_area; + u32 srcID, bytes_written; + int ret; + + work_area = rtas_work_area_alloc(SZ_4K); + if (!work_area) { + pr_err("Could not allocate RTAS buffer for recv pipe\n"); + return -ENOMEM; + } + + ret = rtas_ibm_receive_hvpipe_msg(work_area, &srcID, + &bytes_written); + if (!ret) { + /* + * Recv HVPIPE RTAS is successful. + * When releasing FD or no one is waiting on the + * specific source, issue recv HVPIPE RTAS call + * so that pipe is not blocked - this func is called + * with NULL buf. + */ + if (buf) { + if (size < bytes_written) { + pr_err("Received the payload size = %d, but the buffer size = %d\n", + bytes_written, size); + bytes_written = size; + } + ret = copy_to_user(buf, + rtas_work_area_raw_buf(work_area), + bytes_written); + if (!ret) + ret = bytes_written; + } + } else { + pr_err("ibm,receive-hvpipe-msg failed with %d\n", + ret); + } + + rtas_work_area_free(work_area); + return ret; +} + +/* * papr_hvpipe_handle_write - Issue send HVPIPE RTAS and return - * the RTAS status to the user space + * the size (payload + HVPIPE_HDR_LEN) for RTAS success. + * Otherwise returns the status of RTAS to the user space */ static ssize_t papr_hvpipe_handle_write(struct file *file, const char __user *buf, size_t size, loff_t *off) @@ -215,11 +314,72 @@ static ssize_t papr_hvpipe_handle_read(struct file *file, { struct hvpipe_source_info *src_info = file->private_data; + struct papr_hvpipe_hdr hdr; + long ret; if (!src_info) return -EIO; - return 0; + /* + * Max payload is 4048 (HVPIPE_MAX_WRITE_BUFFER_SIZE) + */ + if ((size > (HVPIPE_HDR_LEN + HVPIPE_MAX_WRITE_BUFFER_SIZE)) || + (size < HVPIPE_HDR_LEN)) + return -EINVAL; + + /* + * Payload is not available to receive or source pipe + * is not closed. + */ + if (!src_info->hvpipe_status) + return 0; + + hdr.version = 0; + hdr.flags = 0; + + /* + * In case if the hvpipe has payload and also the + * hypervisor closed the pipe to the source, retrieve + * the payload and return to the user space first and + * then notify the userspace about the hvpipe close in + * next read(). + */ + if (src_info->hvpipe_status & HVPIPE_MSG_AVAILABLE) + hdr.flags = HVPIPE_MSG_AVAILABLE; + else if (src_info->hvpipe_status & HVPIPE_LOST_CONNECTION) + hdr.flags = HVPIPE_LOST_CONNECTION; + else + /* + * Should not be here without one of the above + * flags set + */ + return -EIO; + + ret = copy_to_user(buf, &hdr, HVPIPE_HDR_LEN); + if (ret) + return ret; + + /* + * Message event has payload, so get the payload with + * recv HVPIPE RTAS. + */ + if (hdr.flags & HVPIPE_MSG_AVAILABLE) { + ret = hvpipe_rtas_recv_msg(buf + HVPIPE_HDR_LEN, + size - HVPIPE_HDR_LEN); + if (ret > 0) { + src_info->hvpipe_status &= ~HVPIPE_MSG_AVAILABLE; + ret += HVPIPE_HDR_LEN; + } + } else if (hdr.flags & HVPIPE_LOST_CONNECTION) { + /* + * Hypervisor is closing the pipe for the specific + * source. So notify user space. + */ + src_info->hvpipe_status &= ~HVPIPE_LOST_CONNECTION; + ret = HVPIPE_HDR_LEN; + } + + return ret; } /* diff --git a/arch/powerpc/platforms/pseries/papr-hvpipe.h b/arch/powerpc/platforms/pseries/papr-hvpipe.h index 6f98da4ec45f..125658e6b596 100644 --- a/arch/powerpc/platforms/pseries/papr-hvpipe.h +++ b/arch/powerpc/platforms/pseries/papr-hvpipe.h @@ -14,6 +14,7 @@ struct hvpipe_source_info { struct list_head list; /* list of sources */ u32 srcID; + u32 hvpipe_status; wait_queue_head_t recv_wqh; /* wake up poll() waitq */ struct task_struct *tsk; }; |