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path: root/drivers/tty/hvc/hvc_xen.c
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Diffstat (limited to 'drivers/tty/hvc/hvc_xen.c')
-rw-r--r--drivers/tty/hvc/hvc_xen.c81
1 files changed, 57 insertions, 24 deletions
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index 5bddb2f5e931..388a71afd6ef 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -43,6 +43,7 @@ struct xencons_info {
int irq;
int vtermno;
grant_ref_t gntref;
+ spinlock_t ring_lock;
};
static LIST_HEAD(xenconsoles);
@@ -83,18 +84,21 @@ static inline void notify_daemon(struct xencons_info *cons)
notify_remote_via_evtchn(cons->evtchn);
}
-static int __write_console(struct xencons_info *xencons,
- const char *data, int len)
+static ssize_t __write_console(struct xencons_info *xencons,
+ const u8 *data, size_t len)
{
XENCONS_RING_IDX cons, prod;
struct xencons_interface *intf = xencons->intf;
- int sent = 0;
+ unsigned long flags;
+ size_t sent = 0;
+ spin_lock_irqsave(&xencons->ring_lock, flags);
cons = intf->out_cons;
prod = intf->out_prod;
mb(); /* update queue values before going on */
if ((prod - cons) > sizeof(intf->out)) {
+ spin_unlock_irqrestore(&xencons->ring_lock, flags);
pr_err_once("xencons: Illegal ring page indices");
return -EINVAL;
}
@@ -104,16 +108,18 @@ static int __write_console(struct xencons_info *xencons,
wmb(); /* write ring before updating pointer */
intf->out_prod = prod;
+ spin_unlock_irqrestore(&xencons->ring_lock, flags);
if (sent)
notify_daemon(xencons);
return sent;
}
-static int domU_write_console(uint32_t vtermno, const char *data, int len)
+static ssize_t domU_write_console(uint32_t vtermno, const u8 *data, size_t len)
{
- int ret = len;
struct xencons_info *cons = vtermno_to_xencons(vtermno);
+ size_t ret = len;
+
if (cons == NULL)
return -EINVAL;
@@ -124,7 +130,7 @@ static int domU_write_console(uint32_t vtermno, const char *data, int len)
* kernel is crippled.
*/
while (len) {
- int sent = __write_console(cons, data, len);
+ ssize_t sent = __write_console(cons, data, len);
if (sent < 0)
return sent;
@@ -139,23 +145,26 @@ static int domU_write_console(uint32_t vtermno, const char *data, int len)
return ret;
}
-static int domU_read_console(uint32_t vtermno, char *buf, int len)
+static ssize_t domU_read_console(uint32_t vtermno, u8 *buf, size_t len)
{
struct xencons_interface *intf;
XENCONS_RING_IDX cons, prod;
- int recv = 0;
struct xencons_info *xencons = vtermno_to_xencons(vtermno);
unsigned int eoiflag = 0;
+ unsigned long flags;
+ size_t recv = 0;
if (xencons == NULL)
return -EINVAL;
intf = xencons->intf;
+ spin_lock_irqsave(&xencons->ring_lock, flags);
cons = intf->in_cons;
prod = intf->in_prod;
mb(); /* get pointers before reading ring */
if ((prod - cons) > sizeof(intf->in)) {
+ spin_unlock_irqrestore(&xencons->ring_lock, flags);
pr_err_once("xencons: Illegal ring page indices");
return -EINVAL;
}
@@ -179,10 +188,13 @@ static int domU_read_console(uint32_t vtermno, char *buf, int len)
xencons->out_cons = intf->out_cons;
xencons->out_cons_same = 0;
}
+ if (!recv && xencons->out_cons_same++ > 1) {
+ eoiflag = XEN_EOI_FLAG_SPURIOUS;
+ }
+ spin_unlock_irqrestore(&xencons->ring_lock, flags);
+
if (recv) {
notify_daemon(xencons);
- } else if (xencons->out_cons_same++ > 1) {
- eoiflag = XEN_EOI_FLAG_SPURIOUS;
}
xen_irq_lateeoi(xencons->irq, eoiflag);
@@ -198,7 +210,7 @@ static const struct hv_ops domU_hvc_ops = {
.notifier_hangup = notifier_hangup_irq,
};
-static int dom0_read_console(uint32_t vtermno, char *buf, int len)
+static ssize_t dom0_read_console(uint32_t vtermno, u8 *buf, size_t len)
{
return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
}
@@ -207,9 +219,9 @@ static int dom0_read_console(uint32_t vtermno, char *buf, int len)
* Either for a dom0 to write to the system console, or a domU with a
* debug version of Xen
*/
-static int dom0_write_console(uint32_t vtermno, const char *str, int len)
+static ssize_t dom0_write_console(uint32_t vtermno, const u8 *str, size_t len)
{
- int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
+ int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (u8 *)str);
if (rc < 0)
return rc;
@@ -239,6 +251,7 @@ static int xen_hvm_console_init(void)
info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
if (!info)
return -ENOMEM;
+ spin_lock_init(&info->ring_lock);
} else if (info->intf != NULL) {
/* already configured */
return 0;
@@ -275,6 +288,7 @@ err:
static int xencons_info_pv_init(struct xencons_info *info, int vtermno)
{
+ spin_lock_init(&info->ring_lock);
info->evtchn = xen_start_info->console.domU.evtchn;
/* GFN == MFN for PV guest */
info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
@@ -325,6 +339,7 @@ static int xen_initial_domain_console_init(void)
info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
if (!info)
return -ENOMEM;
+ spin_lock_init(&info->ring_lock);
}
info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0, false);
@@ -363,18 +378,21 @@ void xen_console_resume(void)
#ifdef CONFIG_HVC_XEN_FRONTEND
static void xencons_disconnect_backend(struct xencons_info *info)
{
- if (info->irq > 0)
- unbind_from_irqhandler(info->irq, NULL);
- info->irq = 0;
+ if (info->hvc != NULL)
+ hvc_remove(info->hvc);
+ info->hvc = NULL;
+ if (info->irq > 0) {
+ evtchn_put(info->evtchn);
+ info->irq = 0;
+ info->evtchn = 0;
+ }
+ /* evtchn_put() will also close it so this is only an error path */
if (info->evtchn > 0)
xenbus_free_evtchn(info->xbdev, info->evtchn);
info->evtchn = 0;
if (info->gntref > 0)
gnttab_free_grant_references(info->gntref);
info->gntref = 0;
- if (info->hvc != NULL)
- hvc_remove(info->hvc);
- info->hvc = NULL;
}
static void xencons_free(struct xencons_info *info)
@@ -419,7 +437,7 @@ static int xencons_connect_backend(struct xenbus_device *dev,
if (ret)
return ret;
info->evtchn = evtchn;
- irq = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn);
+ irq = bind_evtchn_to_irq_lateeoi(evtchn);
if (irq < 0)
return irq;
info->irq = irq;
@@ -482,6 +500,7 @@ static int xencons_probe(struct xenbus_device *dev,
info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
if (!info)
return -ENOMEM;
+ spin_lock_init(&info->ring_lock);
dev_set_drvdata(&dev->dev, info);
info->xbdev = dev;
info->vtermno = xenbus_devid_to_vtermno(devid);
@@ -538,10 +557,23 @@ static void xencons_backend_changed(struct xenbus_device *dev,
if (dev->state == XenbusStateClosed)
break;
fallthrough; /* Missed the backend's CLOSING state */
- case XenbusStateClosing:
+ case XenbusStateClosing: {
+ struct xencons_info *info = dev_get_drvdata(&dev->dev);
+
+ /*
+ * Don't tear down the evtchn and grant ref before the other
+ * end has disconnected, but do stop userspace from trying
+ * to use the device before we allow the backend to close.
+ */
+ if (info->hvc) {
+ hvc_remove(info->hvc);
+ info->hvc = NULL;
+ }
+
xenbus_frontend_closed(dev);
break;
}
+ }
}
static const struct xenbus_device_id xencons_ids[] = {
@@ -573,7 +605,7 @@ static int __init xen_hvc_init(void)
ops = &dom0_hvc_ops;
r = xen_initial_domain_console_init();
if (r < 0)
- return r;
+ goto register_fe;
info = vtermno_to_xencons(HVC_COOKIE);
} else {
ops = &domU_hvc_ops;
@@ -582,7 +614,7 @@ static int __init xen_hvc_init(void)
else
r = xen_pv_console_init();
if (r < 0)
- return r;
+ goto register_fe;
info = vtermno_to_xencons(HVC_COOKIE);
info->irq = bind_evtchn_to_irq_lateeoi(info->evtchn);
@@ -601,12 +633,13 @@ static int __init xen_hvc_init(void)
list_del(&info->list);
spin_unlock_irqrestore(&xencons_lock, flags);
if (info->irq)
- unbind_from_irqhandler(info->irq, NULL);
+ evtchn_put(info->evtchn);
kfree(info);
return r;
}
r = 0;
+ register_fe:
#ifdef CONFIG_HVC_XEN_FRONTEND
r = xenbus_register_frontend(&xencons_driver);
#endif
generated by cgit (git 2.34.1) at 2025-12-25 07:34:25 +0000