Implement a Xen back-end for hvc console. From: Gerd Hoffmann Signed-off-by: Jeremy Fitzhardinge --- arch/i386/xen/Kconfig | 1 arch/i386/xen/events.c | 3 - drivers/Makefile | 3 + drivers/xen/Makefile | 1 drivers/xen/hvc-console.c | 134 +++++++++++++++++++++++++++++++++++++++++++++ include/xen/events.h | 1 6 files changed, 142 insertions(+), 1 deletion(-) =================================================================== --- a/arch/i386/xen/Kconfig +++ b/arch/i386/xen/Kconfig @@ -5,6 +5,7 @@ config XEN config XEN bool "Enable support for Xen hypervisor" depends on PARAVIRT + select HVC_DRIVER default y help This is the Linux Xen port. =================================================================== --- a/arch/i386/xen/events.c +++ b/arch/i386/xen/events.c @@ -219,7 +219,7 @@ static int find_unbound_irq(void) return irq; } -static int bind_evtchn_to_irq(unsigned int evtchn) +int bind_evtchn_to_irq(unsigned int evtchn) { int irq; @@ -244,6 +244,7 @@ static int bind_evtchn_to_irq(unsigned i return irq; } +EXPORT_SYMBOL_GPL(bind_evtchn_to_irq); static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu) { =================================================================== --- a/drivers/Makefile +++ b/drivers/Makefile @@ -14,6 +14,9 @@ obj-$(CONFIG_ACPI) += acpi/ # was used and do nothing if so obj-$(CONFIG_PNP) += pnp/ obj-$(CONFIG_ARM_AMBA) += amba/ + +# Xen is the default console when running as a guest +obj-$(CONFIG_XEN) += xen/ # char/ comes before serial/ etc so that the VT console is the boot-time # default. =================================================================== --- /dev/null +++ b/drivers/xen/Makefile @@ -0,0 +1,1 @@ +obj-y += hvc-console.o =================================================================== --- /dev/null +++ b/drivers/xen/hvc-console.c @@ -0,0 +1,134 @@ +/* + * xen console driver interface to hvc_console.c + * + * (c) 2007 Gerd Hoffmann + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +#include "../char/hvc_console.h" + +#define HVC_COOKIE 0x58656e /* "Xen" in hex */ + +static struct hvc_struct *hvc; +static int xencons_irq; + +/* ------------------------------------------------------------------ */ + +static inline struct xencons_interface *xencons_interface(void) +{ + return mfn_to_virt(xen_start_info->console.domU.mfn); +} + +static inline void notify_daemon(void) +{ + /* Use evtchn: this is called early, before irq is set up. */ + notify_remote_via_evtchn(xen_start_info->console.domU.evtchn); +} + +static int write_console(uint32_t vtermno, const char *data, int len) +{ + struct xencons_interface *intf = xencons_interface(); + XENCONS_RING_IDX cons, prod; + int sent = 0; + + cons = intf->out_cons; + prod = intf->out_prod; + mb(); + BUG_ON((prod - cons) > sizeof(intf->out)); + + while ((sent < len) && ((prod - cons) < sizeof(intf->out))) + intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++]; + + wmb(); + intf->out_prod = prod; + + notify_daemon(); + return sent; +} + +static int read_console(uint32_t vtermno, char *buf, int len) +{ + struct xencons_interface *intf = xencons_interface(); + XENCONS_RING_IDX cons, prod; + int recv = 0; + + cons = intf->in_cons; + prod = intf->in_prod; + mb(); + BUG_ON((prod - cons) > sizeof(intf->in)); + + while (cons != prod && recv < len) + buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++,intf->in)]; + + mb(); + intf->in_cons = cons; + + notify_daemon(); + return recv; +} + +static struct hv_ops hvc_ops = { + .get_chars = read_console, + .put_chars = write_console, +}; + +static int __init xen_init(void) +{ + struct hvc_struct *hp; + + if (!is_running_on_xen()) + return 0; + + xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn); + if (xencons_irq < 0) + xencons_irq = 0 /* NO_IRQ */; + hp = hvc_alloc(HVC_COOKIE, xencons_irq, &hvc_ops, 256); + if (IS_ERR(hp)) + return PTR_ERR(hp); + + hvc = hp; + return 0; +} + +static void __exit xen_fini(void) +{ + if (hvc) + hvc_remove(hvc); +} + +static int xen_cons_init(void) +{ + if (!is_running_on_xen()) + return 0; + + hvc_instantiate(HVC_COOKIE, 0, &hvc_ops); + return 0; +} + +module_init(xen_init); +module_exit(xen_fini); +console_initcall(xen_cons_init); =================================================================== --- a/include/xen/events.h +++ b/include/xen/events.h @@ -13,6 +13,7 @@ enum ipi_vector { XEN_NR_IPIS, }; +int bind_evtchn_to_irq(unsigned int evtchn); int bind_evtchn_to_irqhandler(unsigned int evtchn, irq_handler_t handler, unsigned long irqflags, const char *devname, -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/