diff options
| -rw-r--r-- | drivers/xen/xenbus/xenbus_comms.c | 6 | ||||
| -rw-r--r-- | drivers/xen/xenbus/xenbus_comms.h | 1 | ||||
| -rw-r--r-- | drivers/xen/xenbus/xenbus_dev_backend.c | 51 | ||||
| -rw-r--r-- | include/xen/grant_table.h | 2 | ||||
| -rw-r--r-- | include/xen/xenbus_dev.h | 3 |
5 files changed, 63 insertions, 0 deletions
diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c index 2eff7a6aaa20..52fe7ad07666 100644 --- a/drivers/xen/xenbus/xenbus_comms.c +++ b/drivers/xen/xenbus/xenbus_comms.c @@ -234,3 +234,9 @@ int xb_init_comms(void) return 0; } + +void xb_deinit_comms(void) +{ + unbind_from_irqhandler(xenbus_irq, &xb_waitq); + xenbus_irq = 0; +} diff --git a/drivers/xen/xenbus/xenbus_comms.h b/drivers/xen/xenbus/xenbus_comms.h index 6e42800fa499..c8abd3b8a6c4 100644 --- a/drivers/xen/xenbus/xenbus_comms.h +++ b/drivers/xen/xenbus/xenbus_comms.h @@ -35,6 +35,7 @@ int xs_init(void); int xb_init_comms(void); +void xb_deinit_comms(void); /* Low level routines. */ int xb_write(const void *data, unsigned len); diff --git a/drivers/xen/xenbus/xenbus_dev_backend.c b/drivers/xen/xenbus/xenbus_dev_backend.c index 3d3be78c1093..be738c43104b 100644 --- a/drivers/xen/xenbus/xenbus_dev_backend.c +++ b/drivers/xen/xenbus/xenbus_dev_backend.c @@ -8,7 +8,11 @@ #include <xen/xen.h> #include <xen/page.h> +#include <xen/xenbus.h> #include <xen/xenbus_dev.h> +#include <xen/grant_table.h> +#include <xen/events.h> +#include <asm/xen/hypervisor.h> #include "xenbus_comms.h" @@ -22,6 +26,50 @@ static int xenbus_backend_open(struct inode *inode, struct file *filp) return nonseekable_open(inode, filp); } +static long xenbus_alloc(domid_t domid) +{ + struct evtchn_alloc_unbound arg; + int err = -EEXIST; + + xs_suspend(); + + /* If xenstored_ready is nonzero, that means we have already talked to + * xenstore and set up watches. These watches will be restored by + * xs_resume, but that requires communication over the port established + * below that is not visible to anyone until the ioctl returns. + * + * This can be resolved by splitting the ioctl into two parts + * (postponing the resume until xenstored is active) but this is + * unnecessarily complex for the intended use where xenstored is only + * started once - so return -EEXIST if it's already running. + */ + if (xenstored_ready) + goto out_err; + + gnttab_grant_foreign_access_ref(GNTTAB_RESERVED_XENSTORE, domid, + virt_to_mfn(xen_store_interface), 0 /* writable */); + + arg.dom = DOMID_SELF; + arg.remote_dom = domid; + + err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, &arg); + if (err) + goto out_err; + + if (xen_store_evtchn > 0) + xb_deinit_comms(); + + xen_store_evtchn = arg.port; + + xs_resume(); + + return arg.port; + + out_err: + xs_suspend_cancel(); + return err; +} + static long xenbus_backend_ioctl(struct file *file, unsigned int cmd, unsigned long data) { if (!capable(CAP_SYS_ADMIN)) @@ -33,6 +81,9 @@ static long xenbus_backend_ioctl(struct file *file, unsigned int cmd, unsigned l return xen_store_evtchn; return -ENODEV; + case IOCTL_XENBUS_BACKEND_SETUP: + return xenbus_alloc(data); + default: return -ENOTTY; } diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h index 15f8a00ff003..11e27c3af3cb 100644 --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -46,6 +46,8 @@ #include <xen/features.h> +#define GNTTAB_RESERVED_XENSTORE 1 + /* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */ #define NR_GRANT_FRAMES 4 diff --git a/include/xen/xenbus_dev.h b/include/xen/xenbus_dev.h index ac5f0fe47ed9..bbee8c6a349d 100644 --- a/include/xen/xenbus_dev.h +++ b/include/xen/xenbus_dev.h @@ -38,4 +38,7 @@ #define IOCTL_XENBUS_BACKEND_EVTCHN \ _IOC(_IOC_NONE, 'B', 0, 0) +#define IOCTL_XENBUS_BACKEND_SETUP \ + _IOC(_IOC_NONE, 'B', 1, 0) + #endif /* __LINUX_XEN_XENBUS_DEV_H__ */ |