git: e10b9d6602df - main - bhyve: Move lock of uart frontend to uart backend
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Date: Wed, 01 May 2024 15:33:34 UTC
The branch main has been updated by markj:
URL: https://cgit.FreeBSD.org/src/commit/?id=e10b9d6602dfd876a47f85d8866cabb5a26b8482
commit e10b9d6602dfd876a47f85d8866cabb5a26b8482
Author: SHENG-YI HONG <aokblast@FreeBSD.org>
AuthorDate: 2024-05-01 15:09:31 +0000
Commit: Mark Johnston <markj@FreeBSD.org>
CommitDate: 2024-05-01 15:09:31 +0000
bhyve: Move lock of uart frontend to uart backend
Currently, lock of uart in bhyve is placed in frontend. There are some
problems about it:
1. If every frontend should has a lock, why not move it inside backend
as they all have same uart_softc.
2. If backend needs to modify the information of uart after initialize,
it will be impossible as backend cannot use lock. For example, if we
want implement a telnet support for uart in backend, It should wait
for connection when initialize. After some remote process connect it,
it needs to modify rfd and wfd in backend.
So I decide to move it to backend.
Reviewed by: corvink, jhb, markj
Differential Revision: https://reviews.freebsd.org/D44947
---
usr.sbin/bhyve/uart_backend.c | 22 +++++++++++++++++++++-
usr.sbin/bhyve/uart_backend.h | 3 ++-
usr.sbin/bhyve/uart_emul.c | 15 ++++++---------
usr.sbin/bhyve/uart_pl011.c | 16 ++++++----------
4 files changed, 35 insertions(+), 21 deletions(-)
diff --git a/usr.sbin/bhyve/uart_backend.c b/usr.sbin/bhyve/uart_backend.c
index 8d91f4f671e1..51844cbf1170 100644
--- a/usr.sbin/bhyve/uart_backend.c
+++ b/usr.sbin/bhyve/uart_backend.c
@@ -35,6 +35,7 @@
#include <assert.h>
#include <capsicum_helpers.h>
#include <err.h>
+#include <pthread.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
@@ -66,6 +67,7 @@ struct uart_softc {
struct ttyfd tty;
struct fifo rxfifo;
struct mevent *mev;
+ pthread_mutex_t mtx;
};
static bool uart_stdio; /* stdio in use for i/o */
@@ -325,7 +327,13 @@ uart_tty_backend(struct uart_softc *sc, const char *path)
struct uart_softc *
uart_init(void)
{
- return (calloc(1, sizeof(struct uart_softc)));
+ struct uart_softc *sc = calloc(1, sizeof(struct uart_softc));
+ if (sc == NULL)
+ return (NULL);
+
+ pthread_mutex_init(&sc->mtx, NULL);
+
+ return (sc);
}
int
@@ -346,3 +354,15 @@ uart_tty_open(struct uart_softc *sc, const char *path,
return (retval);
}
+
+void
+uart_softc_lock(struct uart_softc *sc)
+{
+ pthread_mutex_lock(&sc->mtx);
+}
+
+void
+uart_softc_unlock(struct uart_softc *sc)
+{
+ pthread_mutex_unlock(&sc->mtx);
+}
diff --git a/usr.sbin/bhyve/uart_backend.h b/usr.sbin/bhyve/uart_backend.h
index fa7949ad6d1c..ecf785ffd893 100644
--- a/usr.sbin/bhyve/uart_backend.h
+++ b/usr.sbin/bhyve/uart_backend.h
@@ -51,5 +51,6 @@ int uart_rxfifo_snapshot(struct uart_softc *sc,
struct uart_softc *uart_init(void);
int uart_tty_open(struct uart_softc *sc, const char *path,
void (*drain)(int, enum ev_type, void *), void *arg);
-
+void uart_softc_lock(struct uart_softc *sc);
+void uart_softc_unlock(struct uart_softc *sc);
#endif /* _UART_BACKEND_H_ */
diff --git a/usr.sbin/bhyve/uart_emul.c b/usr.sbin/bhyve/uart_emul.c
index 58d6697e4fea..bc71d4760634 100644
--- a/usr.sbin/bhyve/uart_emul.c
+++ b/usr.sbin/bhyve/uart_emul.c
@@ -83,7 +83,6 @@ static struct {
struct uart_ns16550_softc {
struct uart_softc *backend;
- pthread_mutex_t mtx; /* protects all softc elements */
uint8_t data; /* Data register (R/W) */
uint8_t ier; /* Interrupt enable register (R/W) */
uint8_t lcr; /* Line control register (R/W) */
@@ -204,14 +203,14 @@ uart_drain(int fd __unused, enum ev_type ev, void *arg)
* to take out the softc lock to protect against concurrent
* access from a vCPU i/o exit
*/
- pthread_mutex_lock(&sc->mtx);
+ uart_softc_lock(sc->backend);
loopback = (sc->mcr & MCR_LOOPBACK) != 0;
uart_rxfifo_drain(sc->backend, loopback);
if (!loopback)
uart_toggle_intr(sc);
- pthread_mutex_unlock(&sc->mtx);
+ uart_softc_unlock(sc->backend);
}
void
@@ -220,7 +219,7 @@ uart_ns16550_write(struct uart_ns16550_softc *sc, int offset, uint8_t value)
int fifosz;
uint8_t msr;
- pthread_mutex_lock(&sc->mtx);
+ uart_softc_lock(sc->backend);
/*
* Take care of the special case DLAB accesses first
@@ -329,7 +328,7 @@ uart_ns16550_write(struct uart_ns16550_softc *sc, int offset, uint8_t value)
done:
uart_toggle_intr(sc);
- pthread_mutex_unlock(&sc->mtx);
+ uart_softc_unlock(sc->backend);
}
uint8_t
@@ -337,7 +336,7 @@ uart_ns16550_read(struct uart_ns16550_softc *sc, int offset)
{
uint8_t iir, intr_reason, reg;
- pthread_mutex_lock(&sc->mtx);
+ uart_softc_lock(sc->backend);
/*
* Take care of the special case DLAB accesses first
@@ -414,7 +413,7 @@ uart_ns16550_read(struct uart_ns16550_softc *sc, int offset)
done:
uart_toggle_intr(sc);
- pthread_mutex_unlock(&sc->mtx);
+ uart_softc_unlock(sc->backend);
return (reg);
}
@@ -446,8 +445,6 @@ uart_ns16550_init(uart_intr_func_t intr_assert, uart_intr_func_t intr_deassert,
sc->intr_deassert = intr_deassert;
sc->backend = uart_init();
- pthread_mutex_init(&sc->mtx, NULL);
-
uart_reset(sc);
return (sc);
diff --git a/usr.sbin/bhyve/uart_pl011.c b/usr.sbin/bhyve/uart_pl011.c
index e2d5c8bf5657..fb576451c544 100644
--- a/usr.sbin/bhyve/uart_pl011.c
+++ b/usr.sbin/bhyve/uart_pl011.c
@@ -31,7 +31,6 @@
#include <sys/param.h>
#include <assert.h>
-#include <pthread.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
@@ -106,7 +105,6 @@
struct uart_pl011_softc {
struct uart_softc *backend;
- pthread_mutex_t mtx; /* protects all softc elements */
uint16_t irq_state;
@@ -184,7 +182,7 @@ uart_drain(int fd __unused, enum ev_type ev, void *arg)
* to take out the softc lock to protect against concurrent
* access from a vCPU i/o exit
*/
- pthread_mutex_lock(&sc->mtx);
+ uart_softc_lock(sc->backend);
old_size = uart_rxfifo_numchars(sc->backend);
@@ -202,7 +200,7 @@ uart_drain(int fd __unused, enum ev_type ev, void *arg)
if (!loopback)
uart_toggle_intr(sc);
- pthread_mutex_unlock(&sc->mtx);
+ uart_softc_unlock(sc->backend);
}
void
@@ -210,7 +208,7 @@ uart_pl011_write(struct uart_pl011_softc *sc, int offset, uint32_t value)
{
bool loopback;
- pthread_mutex_lock(&sc->mtx);
+ uart_softc_lock(sc->backend);
switch (offset) {
case UARTDR:
loopback = (sc->cr & UARTCR_LBE) != 0;
@@ -266,7 +264,7 @@ uart_pl011_write(struct uart_pl011_softc *sc, int offset, uint32_t value)
break;
}
uart_toggle_intr(sc);
- pthread_mutex_unlock(&sc->mtx);
+ uart_softc_unlock(sc->backend);
}
uint32_t
@@ -276,7 +274,7 @@ uart_pl011_read(struct uart_pl011_softc *sc, int offset)
int fifo_sz;
reg = 0;
- pthread_mutex_lock(&sc->mtx);
+ uart_softc_lock(sc->backend);
switch (offset) {
case UARTDR:
reg = uart_rxfifo_getchar(sc->backend);
@@ -362,7 +360,7 @@ uart_pl011_read(struct uart_pl011_softc *sc, int offset)
break;
}
uart_toggle_intr(sc);
- pthread_mutex_unlock(&sc->mtx);
+ uart_softc_unlock(sc->backend);
return (reg);
}
@@ -380,8 +378,6 @@ uart_pl011_init(uart_intr_func_t intr_assert, uart_intr_func_t intr_deassert,
sc->intr_deassert = intr_deassert;
sc->backend = uart_init();
- pthread_mutex_init(&sc->mtx, NULL);
-
uart_reset(sc);
return (sc);