Both ioeventfd and ipc use an epoll thread roughly the same way. In
order to add a new epoll user, factor the common bits into epoll.c
Slight implementation changes which shouldn't affect behavior:
* At the moment ioeventfd mixes file descriptor (for the stop event) and
pointers in the epoll_event.data union, which could in theory cause
aliasing. Use a pointer for the stop event instead. kvm-ipc uses only
file descriptors. It could be changed but since epoll.c compares the
stop event pointer first, the risk of aliasing with an fd is much
lower there.
* kvm-ipc uses EPOLLET, edge-triggered events, but having the stop event
level-triggered shouldn't make a difference.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
---
Makefile | 1 +
include/kvm/epoll.h | 17 ++++++++
epoll.c | 91 ++++++++++++++++++++++++++++++++++++++
ioeventfd.c | 94 ++++++----------------------------------
kvm-ipc.c | 103 +++++++++++++-------------------------------
5 files changed, 151 insertions(+), 155 deletions(-)
create mode 100644 include/kvm/epoll.h
create mode 100644 epoll.c
diff --git a/Makefile b/Makefile
index 86e19339..6b742369 100644
--- a/Makefile
+++ b/Makefile
@@ -80,6 +80,7 @@ OBJS += virtio/vhost.o
OBJS += disk/blk.o
OBJS += disk/qcow.o
OBJS += disk/raw.o
+OBJS += epoll.o
OBJS += ioeventfd.o
OBJS += net/uip/core.o
OBJS += net/uip/arp.o
diff --git a/include/kvm/epoll.h b/include/kvm/epoll.h
new file mode 100644
index 00000000..dbb5a8d9
--- /dev/null
+++ b/include/kvm/epoll.h
@@ -0,0 +1,17 @@
+#include <sys/epoll.h>
+#include "kvm/kvm.h"
+
+typedef void (*epoll__event_handler_t)(struct kvm *kvm, struct epoll_event *ev);
+
+struct kvm__epoll {
+ int fd;
+ int stop_fd;
+ struct kvm *kvm;
+ const char *name;
+ pthread_t thread;
+ epoll__event_handler_t handle_event;
+};
+
+int epoll__init(struct kvm *kvm, struct kvm__epoll *epoll,
+ const char *name, epoll__event_handler_t handle_event);
+int epoll__exit(struct kvm__epoll *epoll);
diff --git a/epoll.c b/epoll.c
new file mode 100644
index 00000000..8cb0cee5
--- /dev/null
+++ b/epoll.c
@@ -0,0 +1,91 @@
+#include <sys/eventfd.h>
+
+#include "kvm/epoll.h"
+
+#define EPOLLFD_MAX_EVENTS 20
+
+static void *epoll__thread(void *param)
+{
+ u64 stop;
+ int nfds, i;
+ struct kvm__epoll *epoll = param;
+ struct kvm *kvm = epoll->kvm;
+ struct epoll_event events[EPOLLFD_MAX_EVENTS];
+
+ kvm__set_thread_name(epoll->name);
+
+ for (;;) {
+ nfds = epoll_wait(epoll->fd, events, EPOLLFD_MAX_EVENTS, -1);
+ for (i = 0; i < nfds; i++) {
+ if (events[i].data.ptr == &epoll->stop_fd)
+ goto done;
+
+ epoll->handle_event(kvm, &events[i]);
+ }
+ }
+done:
+ if (read(epoll->stop_fd, &stop, sizeof(stop)) < 0)
+ pr_warning("%s: read(stop) failed with %d", __func__, errno);
+ if (write(epoll->stop_fd, &stop, sizeof(stop)) < 0)
+ pr_warning("%s: write(stop) failed with %d", __func__, errno);
+ return NULL;
+}
+
+int epoll__init(struct kvm *kvm, struct kvm__epoll *epoll,
+ const char *name, epoll__event_handler_t handle_event)
+{
+ int r;
+ struct epoll_event stop_event = {
+ .events = EPOLLIN,
+ .data.ptr = &epoll->stop_fd,
+ };
+
+ epoll->kvm = kvm;
+ epoll->name = name;
+ epoll->handle_event = handle_event;
+
+ epoll->fd = epoll_create(EPOLLFD_MAX_EVENTS);
+ if (epoll->fd < 0)
+ return -errno;
+
+ epoll->stop_fd = eventfd(0, 0);
+ if (epoll->stop_fd < 0) {
+ r = -errno;
+ goto err_close_fd;
+ }
+
+ r = epoll_ctl(epoll->fd, EPOLL_CTL_ADD, epoll->stop_fd, &stop_event);
+ if (r < 0)
+ goto err_close_all;
+
+ r = pthread_create(&epoll->thread, NULL, epoll__thread, epoll);
+ if (r < 0)
+ goto err_close_all;
+
+ return 0;
+
+err_close_all:
+ close(epoll->stop_fd);
+err_close_fd:
+ close(epoll->fd);
+
+ return r;
+}
+
+int epoll__exit(struct kvm__epoll *epoll)
+{
+ int r;
+ u64 stop = 1;
+
+ r = write(epoll->stop_fd, &stop, sizeof(stop));
+ if (r < 0)
+ return r;
+
+ r = read(epoll->stop_fd, &stop, sizeof(stop));
+ if (r < 0)
+ return r;
+
+ close(epoll->stop_fd);
+ close(epoll->fd);
+ return 0;
+}
diff --git a/ioeventfd.c b/ioeventfd.c
index 3ae82672..a0fc2578 100644
--- a/ioeventfd.c
+++ b/ioeventfd.c
@@ -9,113 +9,45 @@
#include <linux/kvm.h>
#include <linux/types.h>
+#include "kvm/epoll.h"
#include "kvm/ioeventfd.h"
#include "kvm/kvm.h"
#include "kvm/util.h"
#define IOEVENTFD_MAX_EVENTS 20
-static struct epoll_event events[IOEVENTFD_MAX_EVENTS];
-static int epoll_fd, epoll_stop_fd;
static LIST_HEAD(used_ioevents);
static bool ioeventfd_avail;
+static struct kvm__epoll epoll;
-static void *ioeventfd__thread(void *param)
+static void ioeventfd__handle_event(struct kvm *kvm, struct epoll_event *ev)
{
- u64 tmp = 1;
+ u64 tmp;
+ struct ioevent *ioevent = ev->data.ptr;
- kvm__set_thread_name("ioeventfd-worker");
+ if (read(ioevent->fd, &tmp, sizeof(tmp)) < 0)
+ die("Failed reading event");
- for (;;) {
- int nfds, i;
-
- nfds = epoll_wait(epoll_fd, events, IOEVENTFD_MAX_EVENTS, -1);
- for (i = 0; i < nfds; i++) {
- struct ioevent *ioevent;
-
- if (events[i].data.fd == epoll_stop_fd)
- goto done;
-
- ioevent = events[i].data.ptr;
-
- if (read(ioevent->fd, &tmp, sizeof(tmp)) < 0)
- die("Failed reading event");
-
- ioevent->fn(ioevent->fn_kvm, ioevent->fn_ptr);
- }
- }
-
-done:
- tmp = write(epoll_stop_fd, &tmp, sizeof(tmp));
-
- return NULL;
-}
-
-static int ioeventfd__start(void)
-{
- pthread_t thread;
-
- if (!ioeventfd_avail)
- return -ENOSYS;
-
- return pthread_create(&thread, NULL, ioeventfd__thread, NULL);
+ ioevent->fn(ioevent->fn_kvm, ioevent->fn_ptr);
}
int ioeventfd__init(struct kvm *kvm)
{
- struct epoll_event epoll_event = {.events = EPOLLIN};
- int r;
-
ioeventfd_avail = kvm__supports_extension(kvm, KVM_CAP_IOEVENTFD);
if (!ioeventfd_avail)
return 1; /* Not fatal, but let caller determine no-go. */
- epoll_fd = epoll_create(IOEVENTFD_MAX_EVENTS);
- if (epoll_fd < 0)
- return -errno;
-
- epoll_stop_fd = eventfd(0, 0);
- epoll_event.data.fd = epoll_stop_fd;
-
- r = epoll_ctl(epoll_fd, EPOLL_CTL_ADD, epoll_stop_fd, &epoll_event);
- if (r < 0)
- goto cleanup;
-
- r = ioeventfd__start();
- if (r < 0)
- goto cleanup;
-
- r = 0;
-
- return r;
-
-cleanup:
- close(epoll_stop_fd);
- close(epoll_fd);
-
- return r;
+ return epoll__init(kvm, &epoll, "ioeventfd-worker",
+ ioeventfd__handle_event);
}
base_init(ioeventfd__init);
int ioeventfd__exit(struct kvm *kvm)
{
- u64 tmp = 1;
- int r;
-
if (!ioeventfd_avail)
return 0;
- r = write(epoll_stop_fd, &tmp, sizeof(tmp));
- if (r < 0)
- return r;
-
- r = read(epoll_stop_fd, &tmp, sizeof(tmp));
- if (r < 0)
- return r;
-
- close(epoll_fd);
- close(epoll_stop_fd);
-
+ epoll__exit(&epoll);
return 0;
}
base_exit(ioeventfd__exit);
@@ -165,7 +97,7 @@ int ioeventfd__add_event(struct ioevent *ioevent, int flags)
.data.ptr = new_ioevent,
};
- r = epoll_ctl(epoll_fd, EPOLL_CTL_ADD, event, &epoll_event);
+ r = epoll_ctl(epoll.fd, EPOLL_CTL_ADD, event, &epoll_event);
if (r) {
r = -errno;
goto cleanup;
@@ -213,7 +145,7 @@ int ioeventfd__del_event(u64 addr, u64 datamatch)
ioctl(ioevent->fn_kvm->vm_fd, KVM_IOEVENTFD, &kvm_ioevent);
- epoll_ctl(epoll_fd, EPOLL_CTL_DEL, ioevent->fd, NULL);
+ epoll_ctl(epoll.fd, EPOLL_CTL_DEL, ioevent->fd, NULL);
list_del(&ioevent->list);
diff --git a/kvm-ipc.c b/kvm-ipc.c
index 23f7b12e..265d80c5 100644
--- a/kvm-ipc.c
+++ b/kvm-ipc.c
@@ -2,9 +2,9 @@
#include <sys/un.h>
#include <sys/types.h>
#include <sys/socket.h>
-#include <sys/eventfd.h>
#include <dirent.h>
+#include "kvm/epoll.h"
#include "kvm/kvm-ipc.h"
#include "kvm/rwsem.h"
#include "kvm/read-write.h"
@@ -28,8 +28,8 @@ struct kvm_ipc_head {
extern __thread struct kvm_cpu *current_kvm_cpu;
static void (*msgs[KVM_IPC_MAX_MSGS])(struct kvm *kvm, int fd, u32 type, u32 len, u8 *msg);
static DECLARE_RWSEM(msgs_rwlock);
-static int epoll_fd, server_fd, stop_fd;
-static pthread_t thread;
+static int server_fd;
+static struct kvm__epoll epoll;
static int kvm__create_socket(struct kvm *kvm)
{
@@ -268,7 +268,7 @@ static int kvm_ipc__new_conn(int fd)
ev.events = EPOLLIN | EPOLLRDHUP;
ev.data.fd = client;
- if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client, &ev) < 0) {
+ if (epoll_ctl(epoll.fd, EPOLL_CTL_ADD, client, &ev) < 0) {
close(client);
return -1;
}
@@ -278,7 +278,7 @@ static int kvm_ipc__new_conn(int fd)
static void kvm_ipc__close_conn(int fd)
{
- epoll_ctl(epoll_fd, EPOLL_CTL_DEL, fd, NULL);
+ epoll_ctl(epoll.fd, EPOLL_CTL_DEL, fd, NULL);
close(fd);
}
@@ -309,42 +309,26 @@ done:
return -1;
}
-static void *kvm_ipc__thread(void *param)
+static void kvm_ipc__handle_event(struct kvm *kvm, struct epoll_event *ev)
{
- struct epoll_event event;
- struct kvm *kvm = param;
+ int fd = ev->data.fd;
- kvm__set_thread_name("kvm-ipc");
+ if (fd == server_fd) {
+ int client, r;
- for (;;) {
- int nfds;
+ client = kvm_ipc__new_conn(fd);
+ /*
+ * Handle multiple IPC cmd at a time
+ */
+ do {
+ r = kvm_ipc__receive(kvm, client);
+ } while (r == 0);
- nfds = epoll_wait(epoll_fd, &event, 1, -1);
- if (nfds > 0) {
- int fd = event.data.fd;
-
- if (fd == stop_fd && event.events & EPOLLIN) {
- break;
- } else if (fd == server_fd) {
- int client, r;
-
- client = kvm_ipc__new_conn(fd);
- /*
- * Handle multiple IPC cmd at a time
- */
- do {
- r = kvm_ipc__receive(kvm, client);
- } while (r == 0);
-
- } else if (event.events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
- kvm_ipc__close_conn(fd);
- } else {
- kvm_ipc__receive(kvm, fd);
- }
- }
+ } else if (ev->events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
+ kvm_ipc__close_conn(fd);
+ } else {
+ kvm_ipc__receive(kvm, fd);
}
-
- return NULL;
}
static void kvm__pid(struct kvm *kvm, int fd, u32 type, u32 len, u8 *msg)
@@ -482,42 +466,21 @@ int kvm_ipc__init(struct kvm *kvm)
server_fd = sock;
- epoll_fd = epoll_create(KVM_IPC_MAX_MSGS);
- if (epoll_fd < 0) {
- perror("epoll_create");
- ret = epoll_fd;
+ ret = epoll__init(kvm, &epoll, "kvm-ipc",
+ kvm_ipc__handle_event);
+ if (ret) {
+ pr_err("Failed starting IPC thread");
goto err;
}
ev.events = EPOLLIN | EPOLLET;
ev.data.fd = sock;
- if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) < 0) {
+ if (epoll_ctl(epoll.fd, EPOLL_CTL_ADD, sock, &ev) < 0) {
pr_err("Failed adding socket to epoll");
ret = -EFAULT;
goto err_epoll;
}
- stop_fd = eventfd(0, 0);
- if (stop_fd < 0) {
- perror("eventfd");
- ret = stop_fd;
- goto err_epoll;
- }
-
- ev.events = EPOLLIN | EPOLLET;
- ev.data.fd = stop_fd;
- if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, stop_fd, &ev) < 0) {
- pr_err("Failed adding stop event to epoll");
- ret = -EFAULT;
- goto err_stop;
- }
-
- if (pthread_create(&thread, NULL, kvm_ipc__thread, kvm) != 0) {
- pr_err("Failed starting IPC thread");
- ret = -EFAULT;
- goto err_stop;
- }
-
kvm_ipc__register_handler(KVM_IPC_PID, kvm__pid);
kvm_ipc__register_handler(KVM_IPC_DEBUG, handle_debug);
kvm_ipc__register_handler(KVM_IPC_PAUSE, handle_pause);
@@ -528,10 +491,9 @@ int kvm_ipc__init(struct kvm *kvm)
return 0;
-err_stop:
- close(stop_fd);
err_epoll:
- close(epoll_fd);
+ epoll__exit(&epoll);
+ close(server_fd);
err:
return ret;
}
@@ -539,18 +501,11 @@ base_init(kvm_ipc__init);
int kvm_ipc__exit(struct kvm *kvm)
{
- u64 val = 1;
- int ret;
-
- ret = write(stop_fd, &val, sizeof(val));
- if (ret < 0)
- return ret;
-
+ epoll__exit(&epoll);
close(server_fd);
- close(epoll_fd);
kvm__remove_socket(kvm->cfg.guest_name);
- return ret;
+ return 0;
}
base_exit(kvm_ipc__exit);
--
2.40.1
