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[PATCH v6 12/36] multi-process: add functions to synchronize proxy and r
From: |
elena . ufimtseva |
Subject: |
[PATCH v6 12/36] multi-process: add functions to synchronize proxy and remote endpoints |
Date: |
Mon, 6 Apr 2020 02:41:02 -0700 |
From: Jagannathan Raman <address@hidden>
In some cases, for example MMIO read, QEMU has to wait for the remote to
complete a command before proceeding. An eventfd based mechanism is
added to synchronize QEMU & remote process.
Signed-off-by: John G Johnson <address@hidden>
Signed-off-by: Jagannathan Raman <address@hidden>
Signed-off-by: Elena Ufimtseva <address@hidden>
---
include/io/mpqemu-link.h | 7 +++++++
io/mpqemu-link.c | 41 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 48 insertions(+)
diff --git a/include/io/mpqemu-link.h b/include/io/mpqemu-link.h
index af401e640c..ef95599bca 100644
--- a/include/io/mpqemu-link.h
+++ b/include/io/mpqemu-link.h
@@ -124,4 +124,11 @@ void mpqemu_link_set_callback(MPQemuLinkState *s,
void mpqemu_start_coms(MPQemuLinkState *s, MPQemuChannel* chan);
bool mpqemu_msg_valid(MPQemuMsg *msg);
+#define GET_REMOTE_WAIT eventfd(0, EFD_CLOEXEC)
+#define PUT_REMOTE_WAIT(wait) close(wait)
+#define PROXY_LINK_WAIT_DONE 1
+
+uint64_t wait_for_remote(int efd);
+void notify_proxy(int fd, uint64_t val);
+
#endif
diff --git a/io/mpqemu-link.c b/io/mpqemu-link.c
index b7d3e53ae8..fa9b3a66b1 100644
--- a/io/mpqemu-link.c
+++ b/io/mpqemu-link.c
@@ -10,6 +10,7 @@
#include "qemu/osdep.h"
#include "qemu-common.h"
+#include <poll.h>
#include "qemu/module.h"
#include "io/mpqemu-link.h"
@@ -204,6 +205,46 @@ int mpqemu_msg_recv(MPQemuMsg *msg, MPQemuChannel *chan)
return rc;
}
+uint64_t wait_for_remote(int efd)
+{
+ struct pollfd pfd = { .fd = efd, .events = POLLIN };
+ uint64_t val;
+ int ret;
+
+ ret = poll(&pfd, 1, 1000);
+
+ switch (ret) {
+ case 0:
+ qemu_log_mask(LOG_REMOTE_DEBUG, "Error wait_for_remote: Timed out\n");
+ /* TODO: Kick-off error recovery */
+ return ULLONG_MAX;
+ case -1:
+ qemu_log_mask(LOG_REMOTE_DEBUG, "Poll error wait_for_remote: %s\n",
+ strerror(errno));
+ return ULLONG_MAX;
+ default:
+ if (read(efd, &val, sizeof(val)) == -1) {
+ qemu_log_mask(LOG_REMOTE_DEBUG, "Error wait_for_remote: %s\n",
+ strerror(errno));
+ return ULLONG_MAX;
+ }
+ }
+
+ val = (val == ULLONG_MAX) ? val : (val - 1);
+
+ return val;
+}
+
+void notify_proxy(int efd, uint64_t val)
+{
+ val = (val == ULLONG_MAX) ? val : (val + 1);
+
+ if (write(efd, &val, sizeof(val)) == -1) {
+ qemu_log_mask(LOG_REMOTE_DEBUG, "Error notify_proxy: %s\n",
+ strerror(errno));
+ }
+}
+
static gboolean mpqemu_link_handler_prepare(GSource *gsrc, gint *timeout)
{
g_assert(timeout);
--
2.25.GIT
- [PATCH v6 00/36] Initial support for multi-process qemu, elena . ufimtseva, 2020/04/06
- [PATCH v6 04/36] multi-process: Refactor chardev functions out of vl.c, elena . ufimtseva, 2020/04/06
- [PATCH v6 05/36] multi-process: Refactor monitor functions out of vl.c, elena . ufimtseva, 2020/04/06
- [PATCH v6 01/36] memory: alloc RAM from file at offset, elena . ufimtseva, 2020/04/06
- [PATCH v6 08/36] multi-process: Add stub functions to facilate build of multi-process, elena . ufimtseva, 2020/04/06
- [PATCH v6 07/36] multi-process: add a command line option for debug file, elena . ufimtseva, 2020/04/06
- [PATCH v6 10/36] multi-process: build system for remote device process, elena . ufimtseva, 2020/04/06
- [PATCH v6 12/36] multi-process: add functions to synchronize proxy and remote endpoints,
elena . ufimtseva <=
- [PATCH v6 15/36] multi-process: setup memory manager for remote device, elena . ufimtseva, 2020/04/06
- [PATCH v6 17/36] multi-process: introduce proxy object, elena . ufimtseva, 2020/04/06
- [PATCH v6 16/36] multi-process: remote process initialization, elena . ufimtseva, 2020/04/06
- [PATCH v6 14/36] multi-process: setup a machine object for remote device process, elena . ufimtseva, 2020/04/06
- [PATCH v6 21/36] multi-process: PCI BAR read/write handling for proxy & remote endpoints, elena . ufimtseva, 2020/04/06
- [PATCH v6 18/36] multi-process: Initialize Proxy Object's communication channel, elena . ufimtseva, 2020/04/06