diff options
Diffstat (limited to 'drivers/tty/hvc/hvc_xen.c')
| -rw-r--r-- | drivers/tty/hvc/hvc_xen.c | 69 |
1 files changed, 51 insertions, 18 deletions
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c index 5ef08905fe05..7c23112dc923 100644 --- a/drivers/tty/hvc/hvc_xen.c +++ b/drivers/tty/hvc/hvc_xen.c @@ -37,6 +37,8 @@ struct xencons_info { struct xenbus_device *xbdev; struct xencons_interface *intf; unsigned int evtchn; + XENCONS_RING_IDX out_cons; + unsigned int out_cons_same; struct hvc_struct *hvc; int irq; int vtermno; @@ -86,7 +88,11 @@ static int __write_console(struct xencons_info *xencons, cons = intf->out_cons; prod = intf->out_prod; mb(); /* update queue values before going on */ - BUG_ON((prod - cons) > sizeof(intf->out)); + + if ((prod - cons) > sizeof(intf->out)) { + pr_err_once("xencons: Illegal ring page indices"); + return -EINVAL; + } while ((sent < len) && ((prod - cons) < sizeof(intf->out))) intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++]; @@ -114,7 +120,10 @@ static int domU_write_console(uint32_t vtermno, const char *data, int len) */ while (len) { int sent = __write_console(cons, data, len); - + + if (sent < 0) + return sent; + data += sent; len -= sent; @@ -131,6 +140,8 @@ static int domU_read_console(uint32_t vtermno, char *buf, int len) XENCONS_RING_IDX cons, prod; int recv = 0; struct xencons_info *xencons = vtermno_to_xencons(vtermno); + unsigned int eoiflag = 0; + if (xencons == NULL) return -EINVAL; intf = xencons->intf; @@ -138,7 +149,11 @@ static int domU_read_console(uint32_t vtermno, char *buf, int len) cons = intf->in_cons; prod = intf->in_prod; mb(); /* get pointers before reading ring */ - BUG_ON((prod - cons) > sizeof(intf->in)); + + if ((prod - cons) > sizeof(intf->in)) { + pr_err_once("xencons: Illegal ring page indices"); + return -EINVAL; + } while (cons != prod && recv < len) buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)]; @@ -146,7 +161,27 @@ static int domU_read_console(uint32_t vtermno, char *buf, int len) mb(); /* read ring before consuming */ intf->in_cons = cons; - notify_daemon(xencons); + /* + * When to mark interrupt having been spurious: + * - there was no new data to be read, and + * - the backend did not consume some output bytes, and + * - the previous round with no read data didn't see consumed bytes + * (we might have a race with an interrupt being in flight while + * updating xencons->out_cons, so account for that by allowing one + * round without any visible reason) + */ + if (intf->out_cons != xencons->out_cons) { + xencons->out_cons = intf->out_cons; + xencons->out_cons_same = 0; + } + if (recv) { + notify_daemon(xencons); + } else if (xencons->out_cons_same++ > 1) { + eoiflag = XEN_EOI_FLAG_SPURIOUS; + } + + xen_irq_lateeoi(xencons->irq, eoiflag); + return recv; } @@ -218,7 +253,7 @@ static int xen_hvm_console_init(void) if (r < 0 || v == 0) goto err; gfn = v; - info->intf = xen_remap(gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE); + info->intf = memremap(gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE, MEMREMAP_WB); if (info->intf == NULL) goto err; info->vtermno = HVC_COOKIE; @@ -375,7 +410,7 @@ static int xencons_connect_backend(struct xenbus_device *dev, if (ret) return ret; info->evtchn = evtchn; - irq = bind_evtchn_to_irq(evtchn); + irq = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn); if (irq < 0) return irq; info->irq = irq; @@ -492,7 +527,7 @@ static void xencons_backend_changed(struct xenbus_device *dev, case XenbusStateClosed: if (dev->state == XenbusStateClosed) break; - /* fall through - Missed the backend's CLOSING state. */ + fallthrough; /* Missed the backend's CLOSING state */ case XenbusStateClosing: xenbus_frontend_closed(dev); break; @@ -511,6 +546,7 @@ static struct xenbus_driver xencons_driver = { .remove = xencons_remove, .resume = xencons_resume, .otherend_changed = xencons_backend_changed, + .not_essential = true, }; #endif /* CONFIG_HVC_XEN_FRONTEND */ @@ -539,7 +575,7 @@ static int __init xen_hvc_init(void) return r; info = vtermno_to_xencons(HVC_COOKIE); - info->irq = bind_evtchn_to_irq(info->evtchn); + info->irq = bind_evtchn_to_irq_lateeoi(info->evtchn); } if (info->irq < 0) info->irq = 0; /* NO_IRQ */ @@ -603,14 +639,12 @@ static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) { } #endif #ifdef CONFIG_EARLY_PRINTK -static int __init xenboot_setup_console(struct console *console, char *string) +static int __init xenboot_console_setup(struct console *console, char *string) { static struct xencons_info xenboot; - if (xen_initial_domain()) + if (xen_initial_domain() || !xen_pv_domain()) return 0; - if (!xen_pv_domain()) - return -ENODEV; return xencons_info_pv_init(&xenboot, 0); } @@ -621,17 +655,16 @@ static void xenboot_write_console(struct console *console, const char *string, unsigned int linelen, off = 0; const char *pos; + if (dom0_write_console(0, string, len) >= 0) + return; + if (!xen_pv_domain()) { xen_hvm_early_write(0, string, len); return; } - dom0_write_console(0, string, len); - - if (xen_initial_domain()) + if (domU_write_console(0, "(early) ", 8) < 0) return; - - domU_write_console(0, "(early) ", 8); while (off < len && NULL != (pos = strchr(string+off, '\n'))) { linelen = pos-string+off; if (off + linelen > len) @@ -647,7 +680,7 @@ static void xenboot_write_console(struct console *console, const char *string, struct console xenboot_console = { .name = "xenboot", .write = xenboot_write_console, - .setup = xenboot_setup_console, + .setup = xenboot_console_setup, .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME, .index = -1, }; |