diff options
| -rw-r--r-- | MAINTAINERS | 2 | ||||
| -rw-r--r-- | hw/remote/meson.build | 1 | ||||
| -rw-r--r-- | hw/remote/mpqemu-link.c | 205 | ||||
| -rw-r--r-- | hw/remote/trace-events | 4 | ||||
| -rw-r--r-- | hw/remote/trace.h | 1 | ||||
| -rw-r--r-- | include/hw/remote/mpqemu-link.h | 63 | ||||
| -rw-r--r-- | include/sysemu/iothread.h | 6 | ||||
| -rw-r--r-- | iothread.c | 6 | ||||
| -rw-r--r-- | meson.build | 1 |
9 files changed, 289 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index aad8491..389693f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3211,6 +3211,8 @@ F: hw/pci-host/remote.c F: include/hw/pci-host/remote.h F: hw/remote/machine.c F: include/hw/remote/machine.h +F: hw/remote/mpqemu-link.c +F: include/hw/remote/mpqemu-link.h Build and test automation ------------------------- 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" diff --git a/include/hw/remote/mpqemu-link.h b/include/hw/remote/mpqemu-link.h new file mode 100644 index 0000000..cac699c --- /dev/null +++ b/include/hw/remote/mpqemu-link.h @@ -0,0 +1,63 @@ +/* + * 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. + * + */ + +#ifndef MPQEMU_LINK_H +#define MPQEMU_LINK_H + +#include "qom/object.h" +#include "qemu/thread.h" +#include "io/channel.h" + +#define REMOTE_MAX_FDS 8 + +#define MPQEMU_MSG_HDR_SIZE offsetof(MPQemuMsg, data.u64) + +/** + * MPQemuCmd: + * + * MPQemuCmd enum type to specify the command to be executed on the remote + * device. + * + * This uses a private protocol between QEMU and the remote process. vfio-user + * protocol would supersede this in the future. + * + */ +typedef enum { + MPQEMU_CMD_MAX, +} MPQemuCmd; + +/** + * MPQemuMsg: + * @cmd: The remote command + * @size: Size of the data to be shared + * @data: Structured data + * @fds: File descriptors to be shared with remote device + * + * MPQemuMsg Format of the message sent to the remote device from QEMU. + * + */ +typedef struct { + int cmd; + size_t size; + + union { + uint64_t u64; + } data; + + int fds[REMOTE_MAX_FDS]; + int num_fds; +} MPQemuMsg; + +bool mpqemu_msg_send(MPQemuMsg *msg, QIOChannel *ioc, Error **errp); +bool mpqemu_msg_recv(MPQemuMsg *msg, QIOChannel *ioc, Error **errp); + +bool mpqemu_msg_valid(MPQemuMsg *msg); + +#endif diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h index 0c5284d..f177142 100644 --- a/include/sysemu/iothread.h +++ b/include/sysemu/iothread.h @@ -57,4 +57,10 @@ IOThread *iothread_create(const char *id, Error **errp); void iothread_stop(IOThread *iothread); void iothread_destroy(IOThread *iothread); +/* + * Returns true if executing withing IOThread context, + * false otherwise. + */ +bool qemu_in_iothread(void); + #endif /* IOTHREAD_H */ @@ -369,3 +369,9 @@ IOThread *iothread_by_id(const char *id) { return IOTHREAD(object_resolve_path_type(id, TYPE_IOTHREAD, NULL)); } + +bool qemu_in_iothread(void) +{ + return qemu_get_current_aio_context() == qemu_get_aio_context() ? + false : true; +} diff --git a/meson.build b/meson.build index c8c07df..a923f24 100644 --- a/meson.build +++ b/meson.build @@ -1818,6 +1818,7 @@ if have_system 'net', 'softmmu', 'ui', + 'hw/remote', ] endif if have_system or have_user |