On Tue, Apr 01, 2025 at 01:38:09PM +0200, Eugenio Pérez wrote:
In case the kernel needs to signal an error.
Signed-off-by: Eugenio Pérez <eperezma(a)redhat.com>
---
epoll_type.h | 2 ++
passt.c | 4 ++++
passt.h | 1 +
tap.c | 16 ++++++++++++++++
4 files changed, 23 insertions(+)
diff --git a/epoll_type.h b/epoll_type.h
index 6284c79..6b320db 100644
--- a/epoll_type.h
+++ b/epoll_type.h
@@ -46,6 +46,8 @@ enum epoll_type {
EPOLL_TYPE_REPAIR,
/* vhost-kernel call socket */
EPOLL_TYPE_VHOST_CALL,
+ /* vhost-kernel error socket */
+ EPOLL_TYPE_VHOST_ERROR,
EPOLL_NUM_TYPES,
};
diff --git a/passt.c b/passt.c
index 19c5d5f..2779e0b 100644
--- a/passt.c
+++ b/passt.c
@@ -80,6 +80,7 @@ char *epoll_type_str[] = {
[EPOLL_TYPE_REPAIR_LISTEN] = "TCP_REPAIR helper listening socket",
[EPOLL_TYPE_REPAIR] = "TCP_REPAIR helper socket",
[EPOLL_TYPE_VHOST_CALL] = "vhost-kernel call socket",
+ [EPOLL_TYPE_VHOST_ERROR] = "vhost-kernel error socket",
};
static_assert(ARRAY_SIZE(epoll_type_str) == EPOLL_NUM_TYPES,
"epoll_type_str[] doesn't match enum epoll_type");
@@ -361,6 +362,9 @@ loop:
case EPOLL_TYPE_VHOST_CALL:
vhost_call_cb(&c, ref, &now);
break;
+ case EPOLL_TYPE_VHOST_ERROR:
+ die("Error on vhost-kernel socket");
+ break;
default:
/* Can't happen */
ASSERT(0);
diff --git a/passt.h b/passt.h
index eb5aa03..9e42f3b 100644
--- a/passt.h
+++ b/passt.h
@@ -307,6 +307,7 @@ struct ctx {
int kick_fd;
int call_fd;
+ int err_fd;
} vq[2];
int no_dns;
diff --git a/tap.c b/tap.c
index fbe83aa..b02d3da 100644
--- a/tap.c
+++ b/tap.c
@@ -1552,6 +1552,22 @@ static int tap_ns_tun(void *arg)
if (rc < 0)
die_perror("Failed to add call eventfd to epoll");
c->vq[i].call_fd = file.fd;
+
+ file.fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
+ if (file.fd < 0)
+ die_perror("Failed to create error eventfd");
+
+ rc = ioctl(vhost_fd, VHOST_SET_VRING_ERR, &file);
+ if (rc < 0)
+ die_perror(
+ "VHOST_SET_VRING_ERR ioctl on /dev/vhost-net
failed");
+
+ ref.type = EPOLL_TYPE_VHOST_ERROR, ref.fd = file.fd;
+ ev.data.u64 = ref.u64;
+ rc = epoll_ctl(c->epollfd, EPOLL_CTL_ADD, ref.fd, &ev);
+ if (rc < 0)
+ die_perror("Failed to add error eventfd to epoll");
+ c->vq[i].err_fd = file.fd;
If it's possible to re-initialize vhost, eventually it would be nice
to do so eventually, but for now die()ing is perfectly reasonable.