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-rw-r--r--hw/remote/meson.build1
-rw-r--r--hw/remote/mpqemu-link.c205
-rw-r--r--hw/remote/trace-events4
-rw-r--r--hw/remote/trace.h1
4 files changed, 211 insertions, 0 deletions
diff --git a/hw/remote/meson.build b/hw/remote/meson.build
index 197b038..a2b2fc0 100644
--- a/hw/remote/meson.build
+++ b/hw/remote/meson.build
@@ -1,5 +1,6 @@
remote_ss = ss.source_set()
remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('machine.c'))
+remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('mpqemu-link.c'))
softmmu_ss.add_all(when: 'CONFIG_MULTIPROCESS', if_true: remote_ss)
diff --git a/hw/remote/mpqemu-link.c b/hw/remote/mpqemu-link.c
new file mode 100644
index 0000000..0d1899f
--- /dev/null
+++ b/hw/remote/mpqemu-link.c
@@ -0,0 +1,205 @@
+/*
+ * Communication channel between QEMU and remote device process
+ *
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+
+#include "qemu/module.h"
+#include "hw/remote/mpqemu-link.h"
+#include "qapi/error.h"
+#include "qemu/iov.h"
+#include "qemu/error-report.h"
+#include "qemu/main-loop.h"
+#include "io/channel.h"
+#include "sysemu/iothread.h"
+#include "trace.h"
+
+/*
+ * Send message over the ioc QIOChannel.
+ * This function is safe to call from:
+ * - main loop in co-routine context. Will block the main loop if not in
+ * co-routine context;
+ * - vCPU thread with no co-routine context and if the channel is not part
+ * of the main loop handling;
+ * - IOThread within co-routine context, outside of co-routine context
+ * will block IOThread;
+ * Returns true if no errors were encountered, false otherwise.
+ */
+bool mpqemu_msg_send(MPQemuMsg *msg, QIOChannel *ioc, Error **errp)
+{
+ ERRP_GUARD();
+ bool iolock = qemu_mutex_iothread_locked();
+ bool iothread = qemu_in_iothread();
+ struct iovec send[2] = {};
+ int *fds = NULL;
+ size_t nfds = 0;
+ bool ret = false;
+
+ send[0].iov_base = msg;
+ send[0].iov_len = MPQEMU_MSG_HDR_SIZE;
+
+ send[1].iov_base = (void *)&msg->data;
+ send[1].iov_len = msg->size;
+
+ if (msg->num_fds) {
+ nfds = msg->num_fds;
+ fds = msg->fds;
+ }
+
+ /*
+ * Dont use in IOThread out of co-routine context as
+ * it will block IOThread.
+ */
+ assert(qemu_in_coroutine() || !iothread);
+
+ /*
+ * Skip unlocking/locking iothread lock when the IOThread is running
+ * in co-routine context. Co-routine context is asserted above
+ * for IOThread case.
+ * Also skip lock handling while in a co-routine in the main context.
+ */
+ if (iolock && !iothread && !qemu_in_coroutine()) {
+ qemu_mutex_unlock_iothread();
+ }
+
+ if (!qio_channel_writev_full_all(ioc, send, G_N_ELEMENTS(send),
+ fds, nfds, errp)) {
+ ret = true;
+ } else {
+ trace_mpqemu_send_io_error(msg->cmd, msg->size, nfds);
+ }
+
+ if (iolock && !iothread && !qemu_in_coroutine()) {
+ /* See above comment why skip locking here. */
+ qemu_mutex_lock_iothread();
+ }
+
+ return ret;
+}
+
+/*
+ * Read message from the ioc QIOChannel.
+ * This function is safe to call from:
+ * - From main loop in co-routine context. Will block the main loop if not in
+ * co-routine context;
+ * - From vCPU thread with no co-routine context and if the channel is not part
+ * of the main loop handling;
+ * - From IOThread within co-routine context, outside of co-routine context
+ * will block IOThread;
+ */
+static ssize_t mpqemu_read(QIOChannel *ioc, void *buf, size_t len, int **fds,
+ size_t *nfds, Error **errp)
+{
+ ERRP_GUARD();
+ struct iovec iov = { .iov_base = buf, .iov_len = len };
+ bool iolock = qemu_mutex_iothread_locked();
+ bool iothread = qemu_in_iothread();
+ int ret = -1;
+
+ /*
+ * Dont use in IOThread out of co-routine context as
+ * it will block IOThread.
+ */
+ assert(qemu_in_coroutine() || !iothread);
+
+ if (iolock && !iothread && !qemu_in_coroutine()) {
+ qemu_mutex_unlock_iothread();
+ }
+
+ ret = qio_channel_readv_full_all_eof(ioc, &iov, 1, fds, nfds, errp);
+
+ if (iolock && !iothread && !qemu_in_coroutine()) {
+ qemu_mutex_lock_iothread();
+ }
+
+ return (ret <= 0) ? ret : iov.iov_len;
+}
+
+bool mpqemu_msg_recv(MPQemuMsg *msg, QIOChannel *ioc, Error **errp)
+{
+ ERRP_GUARD();
+ g_autofree int *fds = NULL;
+ size_t nfds = 0;
+ ssize_t len;
+ bool ret = false;
+
+ len = mpqemu_read(ioc, msg, MPQEMU_MSG_HDR_SIZE, &fds, &nfds, errp);
+ if (len <= 0) {
+ goto fail;
+ } else if (len != MPQEMU_MSG_HDR_SIZE) {
+ error_setg(errp, "Message header corrupted");
+ goto fail;
+ }
+
+ if (msg->size > sizeof(msg->data)) {
+ error_setg(errp, "Invalid size for message");
+ goto fail;
+ }
+
+ if (!msg->size) {
+ goto copy_fds;
+ }
+
+ len = mpqemu_read(ioc, &msg->data, msg->size, NULL, NULL, errp);
+ if (len <= 0) {
+ goto fail;
+ }
+ if (len != msg->size) {
+ error_setg(errp, "Unable to read full message");
+ goto fail;
+ }
+
+copy_fds:
+ msg->num_fds = nfds;
+ if (nfds > G_N_ELEMENTS(msg->fds)) {
+ error_setg(errp,
+ "Overflow error: received %zu fds, more than max of %d fds",
+ nfds, REMOTE_MAX_FDS);
+ goto fail;
+ }
+ if (nfds) {
+ memcpy(msg->fds, fds, nfds * sizeof(int));
+ }
+
+ ret = true;
+
+fail:
+ if (*errp) {
+ trace_mpqemu_recv_io_error(msg->cmd, msg->size, nfds);
+ }
+ while (*errp && nfds) {
+ close(fds[nfds - 1]);
+ nfds--;
+ }
+
+ return ret;
+}
+
+bool mpqemu_msg_valid(MPQemuMsg *msg)
+{
+ if (msg->cmd >= MPQEMU_CMD_MAX && msg->cmd < 0) {
+ return false;
+ }
+
+ /* Verify FDs. */
+ if (msg->num_fds >= REMOTE_MAX_FDS) {
+ return false;
+ }
+
+ if (msg->num_fds > 0) {
+ for (int i = 0; i < msg->num_fds; i++) {
+ if (fcntl(msg->fds[i], F_GETFL) == -1) {
+ return false;
+ }
+ }
+ }
+
+ return true;
+}
diff --git a/hw/remote/trace-events b/hw/remote/trace-events
new file mode 100644
index 0000000..0b23974
--- /dev/null
+++ b/hw/remote/trace-events
@@ -0,0 +1,4 @@
+# multi-process trace events
+
+mpqemu_send_io_error(int cmd, int size, int nfds) "send command %d size %d, %d file descriptors to remote process"
+mpqemu_recv_io_error(int cmd, int size, int nfds) "failed to receive %d size %d, %d file descriptors to remote process"
diff --git a/hw/remote/trace.h b/hw/remote/trace.h
new file mode 100644
index 0000000..5d5e3ac
--- /dev/null
+++ b/hw/remote/trace.h
@@ -0,0 +1 @@
+#include "trace/trace-hw_remote.h"
generated by cgit v1.1 at 2024-08-18 04:06:10 +0000