Re: [dpdk-dev] [PATCH v3 2/4] power: extend guest channel api for reading

[Maxime Coquelin]

On 3/21/19 11:55 AM, Hajkowski wrote:

From: Marcin Hajkowski <marcinx.hajkow...@intel.com>

Added new experimental API rte_power_guest_channel_receive_msg
which gives possibility to receive messages send to guest.

Signed-off-by: Marcin Hajkowski <marcinx.hajkow...@intel.com>
---
  lib/librte_power/channel_commands.h    |  5 ++
  lib/librte_power/guest_channel.c       | 65 ++++++++++++++++++++++++++
  lib/librte_power/guest_channel.h       | 35 ++++++++++++++
  lib/librte_power/rte_power_version.map |  1 +
  4 files changed, 106 insertions(+)

diff --git a/lib/librte_power/channel_commands.h 
b/lib/librte_power/channel_commands.h
index e7b93a797..33fd53a6d 100644
--- a/lib/librte_power/channel_commands.h
+++ b/lib/librte_power/channel_commands.h
@@ -28,6 +28,11 @@ extern "C" {
  #define CPU_POWER_SCALE_MIN     4
  #define CPU_POWER_ENABLE_TURBO  5
  #define CPU_POWER_DISABLE_TURBO 6
+
+/* Generic Power Command Response */
+#define CPU_POWER_CMD_ACK       1
+#define CPU_POWER_CMD_NACK      2
+
  #define HOURS 24

#define MAX_VFS 10

diff --git a/lib/librte_power/guest_channel.c b/lib/librte_power/guest_channel.c
index 9cf7d2cb2..3213fa769 100644
--- a/lib/librte_power/guest_channel.c
+++ b/lib/librte_power/guest_channel.c
@@ -10,6 +10,7 @@
  #include <fcntl.h>
  #include <string.h>
  #include <errno.h>
+#include <poll.h>

#include <rte_log.h>

@@ -19,6 +20,9 @@

#define RTE_LOGTYPE_GUEST_CHANNEL RTE_LOGTYPE_USER1 +/* Timeout for incoming message in milliseconds. */

+#define TIMEOUT 10
+
  static int global_fds[RTE_MAX_LCORE] = { [0 ... RTE_MAX_LCORE-1] = -1 };

int

@@ -125,6 +129,67 @@ int rte_power_guest_channel_send_msg(struct channel_packet 
*pkt,
        return guest_channel_send_msg(pkt, lcore_id);
  }

+int power_guest_channel_read_msg(struct channel_packet *pkt,

+                       unsigned int lcore_id)
+{
+       int ret;
+
+       struct pollfd fds;
+       fds.fd = global_fds[lcore_id];
+       fds.events = POLLIN;
+
+       ret = poll(&fds, 1, TIMEOUT);
+       if (ret == 0) {
+               RTE_LOG(DEBUG, GUEST_CHANNEL, "Timeout occurs during poll 
function.\n");
+               return -1;
+       } else if (ret < 0) {
+               RTE_LOG(ERR, GUEST_CHANNEL, "Error occurred during poll function: 
%s\n",
+                               strerror(ret));
+               return -1;
+       }
+
+       void *buffer = pkt;

I would prefer it to be declared at the beginning of the function,
but at least, declare it just before the while loop.

+
+       if (lcore_id >= RTE_MAX_LCORE) {
+               RTE_LOG(ERR, GUEST_CHANNEL, "Channel(%u) is out of range 
0...%d\n",
+                               lcore_id, RTE_MAX_LCORE-1);
+               return -1;
+       }
+
+       if (global_fds[lcore_id] < 0) {
+               RTE_LOG(ERR, GUEST_CHANNEL, "Channel is not connected\n");
+               return -1;
+       }
+
+       int buffer_len = sizeof(*pkt);
+
+       while (buffer_len > 0) {
+               ret = read(global_fds[lcore_id],
+                               buffer, buffer_len);
+               if (ret < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       return -1;
+               }
+               /* No data has been read, this can indicate not
+                * consistent buffer_len with actual data size.
+                */
+               if (ret == 0) {
+                       RTE_LOG(ERR, GUEST_CHANNEL, "No more data has been 
read.\n");
+                       return -1;
+               }
+               buffer = (char *)buffer + ret;
+               buffer_len -= ret;
+       }
+
+       return 0;
+}
+