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tools/libs/evtchn: replace assert()s in stubdom with proper locking

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In tools/libs/evtchn/minios.c there are assert()s for the current
thread being the main thread when binding an event channel.

As Mini-OS is supporting multiple threads, there is no real reason
why the binding shouldn't be allowed to happen in any other thread.

Drop the assert()s and replace them with proper locking of the
port_list.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
This commit is contained in:
Juergen Gross authored and Andrew Cooper committed 2023-12-07 20:10:57 +00:00
1 parent e6e8c5831a
commit bc4fe94a69
1 file changed
+54 -25
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tools/libs/evtchn/minios.c
+54 -25
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@@ -25,6 +25,7 @@
#include <mini-os/os.h> #include <mini-os/os.h>
#include <mini-os/lib.h> #include <mini-os/lib.h>
#include <mini-os/events.h> #include <mini-os/events.h>
#include <mini-os/semaphore.h>
#include <mini-os/wait.h> #include <mini-os/wait.h>
#include <assert.h> #include <assert.h>
@@ -40,6 +41,11 @@
XEN_LIST_HEAD(port_list, struct port_info); XEN_LIST_HEAD(port_list, struct port_info);
struct ports {
struct port_list list;
struct semaphore sem;
};
struct port_info { struct port_info {
XEN_LIST_ENTRY(struct port_info) list; XEN_LIST_ENTRY(struct port_info) list;
evtchn_port_t port; evtchn_port_t port;
@@ -47,12 +53,11 @@ struct port_info {
bool bound; bool bound;
}; };
/* XXX Note: This is not threadsafe */
static struct port_info *port_alloc(xenevtchn_handle *xce) static struct port_info *port_alloc(xenevtchn_handle *xce)
{ {
struct port_info *port_info; struct port_info *port_info;
struct file *file = get_file_from_fd(xce->fd); struct file *file = get_file_from_fd(xce->fd);
struct port_list *port_list = file->dev; struct ports *ports = file->dev;
port_info = malloc(sizeof(struct port_info)); port_info = malloc(sizeof(struct port_info));
if ( port_info == NULL ) if ( port_info == NULL )
@@ -62,7 +67,9 @@ static struct port_info *port_alloc(xenevtchn_handle *xce)
port_info->port = -1; port_info->port = -1;
port_info->bound = false; port_info->bound = false;
XEN_LIST_INSERT_HEAD(port_list, port_info, list); down(&ports->sem);
XEN_LIST_INSERT_HEAD(&ports->list, port_info, list);
up(&ports->sem);
return port_info; return port_info;
} }
@@ -79,11 +86,12 @@ static void port_dealloc(struct port_info *port_info)
static int evtchn_close_fd(struct file *file) static int evtchn_close_fd(struct file *file)
{ {
struct port_info *port_info, *tmp; struct port_info *port_info, *tmp;
struct port_list *port_list = file->dev; struct ports *ports = file->dev;
XEN_LIST_FOREACH_SAFE(port_info, port_list, list, tmp) XEN_LIST_FOREACH_SAFE(port_info, &ports->list, list, tmp)
port_dealloc(port_info); port_dealloc(port_info);
free(port_list);
free(ports);
return 0; return 0;
} }
@@ -110,10 +118,10 @@ int osdep_evtchn_open(xenevtchn_handle *xce, unsigned int flags)
{ {
int fd; int fd;
struct file *file; struct file *file;
struct port_list *list; struct ports *ports;
list = malloc(sizeof(*list)); ports = malloc(sizeof(*ports));
if ( !list ) if ( !ports )
return -1; return -1;
fd = alloc_fd(ftype_evtchn); fd = alloc_fd(ftype_evtchn);
@@ -121,12 +129,13 @@ int osdep_evtchn_open(xenevtchn_handle *xce, unsigned int flags)
if ( !file ) if ( !file )
{ {
free(list); free(ports);
return -1; return -1;
} }
file->dev = list; file->dev = ports;
XEN_LIST_INIT(list); XEN_LIST_INIT(&ports->list);
init_SEMAPHORE(&ports->sem, 1);
xce->fd = fd; xce->fd = fd;
printf("evtchn_open() -> %d\n", fd); printf("evtchn_open() -> %d\n", fd);
@@ -168,16 +177,22 @@ static void evtchn_handler(evtchn_port_t port, struct pt_regs *regs, void *data)
xenevtchn_handle *xce = data; xenevtchn_handle *xce = data;
struct file *file = get_file_from_fd(xce->fd); struct file *file = get_file_from_fd(xce->fd);
struct port_info *port_info; struct port_info *port_info;
struct port_list *port_list; struct ports *ports;
assert(file); assert(file);
port_list = file->dev; ports = file->dev;
mask_evtchn(port); mask_evtchn(port);
XEN_LIST_FOREACH(port_info, port_list, list)
down(&ports->sem);
XEN_LIST_FOREACH(port_info, &ports->list, list)
{ {
if ( port_info->port == port ) if ( port_info->port == port )
{
up(&ports->sem);
goto found; goto found;
}
} }
up(&ports->sem);
printk("Unknown port %d for handle %d\n", port, xce->fd); printk("Unknown port %d for handle %d\n", port, xce->fd);
return; return;
@@ -188,6 +203,16 @@ static void evtchn_handler(evtchn_port_t port, struct pt_regs *regs, void *data)
wake_up(&event_queue); wake_up(&event_queue);
} }
static void port_remove(xenevtchn_handle *xce, struct port_info *port_info)
{
struct file *file = get_file_from_fd(xce->fd);
struct ports *ports = file->dev;
down(&ports->sem);
port_dealloc(port_info);
up(&ports->sem);
}
xenevtchn_port_or_error_t xenevtchn_bind_unbound_port(xenevtchn_handle *xce, xenevtchn_port_or_error_t xenevtchn_bind_unbound_port(xenevtchn_handle *xce,
uint32_t domid) uint32_t domid)
{ {
@@ -195,7 +220,6 @@ xenevtchn_port_or_error_t xenevtchn_bind_unbound_port(xenevtchn_handle *xce,
int ret; int ret;
evtchn_port_t port; evtchn_port_t port;
assert(get_current() == main_thread);
port_info = port_alloc(xce); port_info = port_alloc(xce);
if ( port_info == NULL ) if ( port_info == NULL )
return -1; return -1;
@@ -206,7 +230,7 @@ xenevtchn_port_or_error_t xenevtchn_bind_unbound_port(xenevtchn_handle *xce,
if ( ret < 0 ) if ( ret < 0 )
{ {
port_dealloc(port_info); port_remove(xce, port_info);
errno = -ret; errno = -ret;
return -1; return -1;
} }
@@ -226,7 +250,6 @@ xenevtchn_port_or_error_t xenevtchn_bind_interdomain(xenevtchn_handle *xce,
evtchn_port_t local_port; evtchn_port_t local_port;
int ret; int ret;
assert(get_current() == main_thread);
port_info = port_alloc(xce); port_info = port_alloc(xce);
if ( port_info == NULL ) if ( port_info == NULL )
return -1; return -1;
@@ -238,7 +261,7 @@ xenevtchn_port_or_error_t xenevtchn_bind_interdomain(xenevtchn_handle *xce,
if ( ret < 0 ) if ( ret < 0 )
{ {
port_dealloc(port_info); port_remove(xce, port_info);
errno = -ret; errno = -ret;
return -1; return -1;
} }
@@ -255,16 +278,19 @@ int xenevtchn_unbind(xenevtchn_handle *xce, evtchn_port_t port)
int fd = xce->fd; int fd = xce->fd;
struct file *file = get_file_from_fd(fd); struct file *file = get_file_from_fd(fd);
struct port_info *port_info; struct port_info *port_info;
struct port_list *port_list = file->dev; struct ports *ports = file->dev;
XEN_LIST_FOREACH(port_info, port_list, list) down(&ports->sem);
XEN_LIST_FOREACH(port_info, &ports->list, list)
{ {
if ( port_info->port == port ) if ( port_info->port == port )
{ {
port_dealloc(port_info); port_dealloc(port_info);
up(&ports->sem);
return 0; return 0;
} }
} }
up(&ports->sem);
printf("Warning: couldn't find port %"PRId32" for xc handle %x\n", printf("Warning: couldn't find port %"PRId32" for xc handle %x\n",
port, fd); port, fd);
@@ -279,7 +305,6 @@ xenevtchn_port_or_error_t xenevtchn_bind_virq(xenevtchn_handle *xce,
struct port_info *port_info; struct port_info *port_info;
evtchn_port_t port; evtchn_port_t port;
assert(get_current() == main_thread);
port_info = port_alloc(xce); port_info = port_alloc(xce);
if ( port_info == NULL ) if ( port_info == NULL )
return -1; return -1;
@@ -290,7 +315,7 @@ xenevtchn_port_or_error_t xenevtchn_bind_virq(xenevtchn_handle *xce,
if ( port < 0 ) if ( port < 0 )
{ {
port_dealloc(port_info); port_remove(xce, port_info);
errno = -port; errno = -port;
return -1; return -1;
} }
@@ -306,15 +331,17 @@ xenevtchn_port_or_error_t xenevtchn_pending(xenevtchn_handle *xce)
{ {
struct file *file = get_file_from_fd(xce->fd); struct file *file = get_file_from_fd(xce->fd);
struct port_info *port_info; struct port_info *port_info;
struct port_list *port_list = file->dev; struct ports *ports = file->dev;
unsigned long flags; unsigned long flags;
evtchn_port_t ret = -1; evtchn_port_t ret = -1;
down(&ports->sem);
local_irq_save(flags); local_irq_save(flags);
file->read = false; file->read = false;
XEN_LIST_FOREACH(port_info, port_list, list) XEN_LIST_FOREACH(port_info, &ports->list, list)
{ {
if ( port_info->port != -1 && port_info->pending ) if ( port_info->port != -1 && port_info->pending )
{ {
@@ -333,6 +360,8 @@ xenevtchn_port_or_error_t xenevtchn_pending(xenevtchn_handle *xce)
local_irq_restore(flags); local_irq_restore(flags);
up(&ports->sem);
return ret; return ret;
} }
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