hvc_xen: implement multiconsole support

This patch implements support for multiple consoles:
consoles other than the first one are setup using the traditional xenbus
and grant-table based mechanism.
We use a list to keep track of the allocated consoles, we don't
expect too many of them anyway.

Changes in v3:

- call hvc_remove before removing the console from xenconsoles;
- do not lock xencons_lock twice in the destruction path;
- use the DEFINE_XENBUS_DRIVER macro.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Stefano Stabellini 2012-01-30 16:02:31 +00:00 committed by Konrad Rzeszutek Wilk
parent eb5ef07151
commit 02e19f9c7c

View File

@ -23,6 +23,7 @@
#include <linux/err.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/list.h>
#include <asm/io.h>
#include <asm/xen/hypervisor.h>
@ -30,47 +31,67 @@
#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <xen/hvm.h>
#include <xen/grant_table.h>
#include <xen/page.h>
#include <xen/events.h>
#include <xen/interface/io/console.h>
#include <xen/hvc-console.h>
#include <xen/xenbus.h>
#include "hvc_console.h"
#define HVC_COOKIE 0x58656e /* "Xen" in hex */
static struct hvc_struct *hvc;
static int xencons_irq;
struct xencons_info {
struct list_head list;
struct xenbus_device *xbdev;
struct xencons_interface *intf;
unsigned int evtchn;
struct hvc_struct *hvc;
int irq;
int vtermno;
grant_ref_t gntref;
};
static LIST_HEAD(xenconsoles);
static DEFINE_SPINLOCK(xencons_lock);
static struct xenbus_driver xencons_driver;
/* ------------------------------------------------------------------ */
static unsigned long console_pfn = ~0ul;
static unsigned int console_evtchn = ~0ul;
static struct xencons_interface *xencons_if = NULL;
static inline struct xencons_interface *xencons_interface(void)
static struct xencons_info *vtermno_to_xencons(int vtermno)
{
if (xencons_if != NULL)
return xencons_if;
if (console_pfn == ~0ul)
return mfn_to_virt(xen_start_info->console.domU.mfn);
else
return __va(console_pfn << PAGE_SHIFT);
struct xencons_info *entry, *n, *ret = NULL;
if (list_empty(&xenconsoles))
return NULL;
list_for_each_entry_safe(entry, n, &xenconsoles, list) {
if (entry->vtermno == vtermno) {
ret = entry;
break;
}
}
return ret;
}
static inline void notify_daemon(void)
static inline int xenbus_devid_to_vtermno(int devid)
{
return devid + HVC_COOKIE;
}
static inline void notify_daemon(struct xencons_info *cons)
{
/* Use evtchn: this is called early, before irq is set up. */
if (console_evtchn == ~0ul)
notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);
else
notify_remote_via_evtchn(console_evtchn);
notify_remote_via_evtchn(cons->evtchn);
}
static int __write_console(const char *data, int len)
static int __write_console(struct xencons_info *xencons,
const char *data, int len)
{
struct xencons_interface *intf = xencons_interface();
XENCONS_RING_IDX cons, prod;
struct xencons_interface *intf = xencons->intf;
int sent = 0;
cons = intf->out_cons;
@ -85,13 +106,16 @@ static int __write_console(const char *data, int len)
intf->out_prod = prod;
if (sent)
notify_daemon();
notify_daemon(xencons);
return sent;
}
static int domU_write_console(uint32_t vtermno, const char *data, int len)
{
int ret = len;
struct xencons_info *cons = vtermno_to_xencons(vtermno);
if (cons == NULL)
return -EINVAL;
/*
* Make sure the whole buffer is emitted, polling if
@ -100,7 +124,7 @@ static int domU_write_console(uint32_t vtermno, const char *data, int len)
* kernel is crippled.
*/
while (len) {
int sent = __write_console(data, len);
int sent = __write_console(cons, data, len);
data += sent;
len -= sent;
@ -114,9 +138,13 @@ static int domU_write_console(uint32_t vtermno, const char *data, int len)
static int domU_read_console(uint32_t vtermno, char *buf, int len)
{
struct xencons_interface *intf = xencons_interface();
struct xencons_interface *intf;
XENCONS_RING_IDX cons, prod;
int recv = 0;
struct xencons_info *xencons = vtermno_to_xencons(vtermno);
if (xencons == NULL)
return -EINVAL;
intf = xencons->intf;
cons = intf->in_cons;
prod = intf->in_prod;
@ -129,7 +157,7 @@ static int domU_read_console(uint32_t vtermno, char *buf, int len)
mb(); /* read ring before consuming */
intf->in_cons = cons;
notify_daemon();
notify_daemon(xencons);
return recv;
}
@ -172,78 +200,359 @@ static int xen_hvm_console_init(void)
int r;
uint64_t v = 0;
unsigned long mfn;
struct xencons_info *info;
if (!xen_hvm_domain())
return -ENODEV;
if (xencons_if != NULL)
return -EBUSY;
info = vtermno_to_xencons(HVC_COOKIE);
if (!info) {
info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL | __GFP_ZERO);
if (!info)
return -ENOMEM;
}
/* already configured */
if (info->intf != NULL)
return 0;
r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
if (r < 0)
if (r < 0) {
kfree(info);
return -ENODEV;
console_evtchn = v;
}
info->evtchn = v;
hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
if (r < 0)
if (r < 0) {
kfree(info);
return -ENODEV;
}
mfn = v;
xencons_if = ioremap(mfn << PAGE_SHIFT, PAGE_SIZE);
if (xencons_if == NULL)
info->intf = ioremap(mfn << PAGE_SHIFT, PAGE_SIZE);
if (info->intf == NULL) {
kfree(info);
return -ENODEV;
}
info->vtermno = HVC_COOKIE;
spin_lock(&xencons_lock);
list_add_tail(&info->list, &xenconsoles);
spin_unlock(&xencons_lock);
return 0;
}
static int xen_pv_console_init(void)
{
struct xencons_info *info;
if (!xen_pv_domain())
return -ENODEV;
if (!xen_start_info->console.domU.evtchn)
return -ENODEV;
info = vtermno_to_xencons(HVC_COOKIE);
if (!info) {
info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL | __GFP_ZERO);
if (!info)
return -ENOMEM;
}
/* already configured */
if (info->intf != NULL)
return 0;
info->evtchn = xen_start_info->console.domU.evtchn;
info->intf = mfn_to_virt(xen_start_info->console.domU.mfn);
info->vtermno = HVC_COOKIE;
spin_lock(&xencons_lock);
list_add_tail(&info->list, &xenconsoles);
spin_unlock(&xencons_lock);
return 0;
}
static int xen_initial_domain_console_init(void)
{
struct xencons_info *info;
if (!xen_initial_domain())
return -ENODEV;
info = vtermno_to_xencons(HVC_COOKIE);
if (!info) {
info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL | __GFP_ZERO);
if (!info)
return -ENOMEM;
}
info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0);
info->vtermno = HVC_COOKIE;
spin_lock(&xencons_lock);
list_add_tail(&info->list, &xenconsoles);
spin_unlock(&xencons_lock);
return 0;
}
static int __init xen_hvc_init(void)
{
struct hvc_struct *hp;
struct hv_ops *ops;
int r;
struct xencons_info *info;
const struct hv_ops *ops;
if (!xen_domain())
return -ENODEV;
if (xen_initial_domain()) {
ops = &dom0_hvc_ops;
xencons_irq = bind_virq_to_irq(VIRQ_CONSOLE, 0);
r = xen_initial_domain_console_init();
if (r < 0)
return r;
info = vtermno_to_xencons(HVC_COOKIE);
} else {
ops = &domU_hvc_ops;
if (xen_pv_domain()) {
if (!xen_start_info->console.domU.evtchn)
return -ENODEV;
console_pfn = mfn_to_pfn(xen_start_info->console.domU.mfn);
console_evtchn = xen_start_info->console.domU.evtchn;
} else {
if (xen_hvm_domain())
r = xen_hvm_console_init();
if (r < 0)
return r;
}
xencons_irq = bind_evtchn_to_irq(console_evtchn);
if (xencons_irq < 0)
xencons_irq = 0; /* NO_IRQ */
else
irq_set_noprobe(xencons_irq);
r = xen_pv_console_init();
if (r < 0)
return r;
info = vtermno_to_xencons(HVC_COOKIE);
info->irq = bind_evtchn_to_irq(info->evtchn);
}
if (info->irq < 0)
info->irq = 0; /* NO_IRQ */
else
irq_set_noprobe(info->irq);
info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
if (IS_ERR(info->hvc)) {
r = PTR_ERR(info->hvc);
spin_lock(&xencons_lock);
list_del(&info->list);
spin_unlock(&xencons_lock);
if (info->irq)
unbind_from_irqhandler(info->irq, NULL);
kfree(info);
return r;
}
hp = hvc_alloc(HVC_COOKIE, xencons_irq, ops, 256);
if (IS_ERR(hp))
return PTR_ERR(hp);
hvc = hp;
return 0;
return xenbus_register_frontend(&xencons_driver);
}
void xen_console_resume(void)
{
if (xencons_irq)
rebind_evtchn_irq(console_evtchn, xencons_irq);
struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
if (info != NULL && info->irq)
rebind_evtchn_irq(info->evtchn, info->irq);
}
static void xencons_disconnect_backend(struct xencons_info *info)
{
if (info->irq > 0)
unbind_from_irqhandler(info->irq, NULL);
info->irq = 0;
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)
{
free_page((unsigned long)info->intf);
info->intf = NULL;
info->vtermno = 0;
kfree(info);
}
static int xen_console_remove(struct xencons_info *info)
{
xencons_disconnect_backend(info);
spin_lock(&xencons_lock);
list_del(&info->list);
spin_unlock(&xencons_lock);
if (info->xbdev != NULL)
xencons_free(info);
else {
if (xen_hvm_domain())
iounmap(info->intf);
kfree(info);
}
return 0;
}
static int xencons_remove(struct xenbus_device *dev)
{
return xen_console_remove(dev_get_drvdata(&dev->dev));
}
static int xencons_connect_backend(struct xenbus_device *dev,
struct xencons_info *info)
{
int ret, evtchn, devid, ref, irq;
struct xenbus_transaction xbt;
grant_ref_t gref_head;
unsigned long mfn;
ret = xenbus_alloc_evtchn(dev, &evtchn);
if (ret)
return ret;
info->evtchn = evtchn;
irq = bind_evtchn_to_irq(evtchn);
if (irq < 0)
return irq;
info->irq = irq;
devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
irq, &domU_hvc_ops, 256);
if (IS_ERR(info->hvc))
return PTR_ERR(info->hvc);
if (xen_pv_domain())
mfn = virt_to_mfn(info->intf);
else
mfn = __pa(info->intf) >> PAGE_SHIFT;
ret = gnttab_alloc_grant_references(1, &gref_head);
if (ret < 0)
return ret;
info->gntref = gref_head;
ref = gnttab_claim_grant_reference(&gref_head);
if (ref < 0)
return ref;
gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
mfn, 0);
again:
ret = xenbus_transaction_start(&xbt);
if (ret) {
xenbus_dev_fatal(dev, ret, "starting transaction");
return ret;
}
ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
if (ret)
goto error_xenbus;
ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
evtchn);
if (ret)
goto error_xenbus;
ret = xenbus_printf(xbt, dev->nodename, "type", "ioemu");
if (ret)
goto error_xenbus;
ret = xenbus_transaction_end(xbt, 0);
if (ret) {
if (ret == -EAGAIN)
goto again;
xenbus_dev_fatal(dev, ret, "completing transaction");
return ret;
}
xenbus_switch_state(dev, XenbusStateInitialised);
return 0;
error_xenbus:
xenbus_transaction_end(xbt, 1);
xenbus_dev_fatal(dev, ret, "writing xenstore");
return ret;
}
static int __devinit xencons_probe(struct xenbus_device *dev,
const struct xenbus_device_id *id)
{
int ret, devid;
struct xencons_info *info;
devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
if (devid == 0)
return -ENODEV;
info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL | __GFP_ZERO);
if (!info)
goto error_nomem;
dev_set_drvdata(&dev->dev, info);
info->xbdev = dev;
info->vtermno = xenbus_devid_to_vtermno(devid);
info->intf = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
if (!info->intf)
goto error_nomem;
ret = xencons_connect_backend(dev, info);
if (ret < 0)
goto error;
spin_lock(&xencons_lock);
list_add_tail(&info->list, &xenconsoles);
spin_unlock(&xencons_lock);
return 0;
error_nomem:
ret = -ENOMEM;
xenbus_dev_fatal(dev, ret, "allocating device memory");
error:
xencons_disconnect_backend(info);
xencons_free(info);
return ret;
}
static int xencons_resume(struct xenbus_device *dev)
{
struct xencons_info *info = dev_get_drvdata(&dev->dev);
xencons_disconnect_backend(info);
memset(info->intf, 0, PAGE_SIZE);
return xencons_connect_backend(dev, info);
}
static void xencons_backend_changed(struct xenbus_device *dev,
enum xenbus_state backend_state)
{
switch (backend_state) {
case XenbusStateReconfiguring:
case XenbusStateReconfigured:
case XenbusStateInitialising:
case XenbusStateInitialised:
case XenbusStateUnknown:
case XenbusStateClosed:
break;
case XenbusStateInitWait:
break;
case XenbusStateConnected:
xenbus_switch_state(dev, XenbusStateConnected);
break;
case XenbusStateClosing:
xenbus_frontend_closed(dev);
break;
}
}
static const struct xenbus_device_id xencons_ids[] = {
{ "console" },
{ "" }
};
static void __exit xen_hvc_fini(void)
{
if (hvc)
hvc_remove(hvc);
struct xencons_info *entry, *next;
if (list_empty(&xenconsoles))
return;
list_for_each_entry_safe(entry, next, &xenconsoles, list) {
xen_console_remove(entry);
}
}
static int xen_cons_init(void)
@ -256,18 +565,28 @@ static int xen_cons_init(void)
if (xen_initial_domain())
ops = &dom0_hvc_ops;
else {
int r;
ops = &domU_hvc_ops;
if (xen_pv_domain())
console_evtchn = xen_start_info->console.domU.evtchn;
if (xen_hvm_domain())
r = xen_hvm_console_init();
else
xen_hvm_console_init();
r = xen_pv_console_init();
if (r < 0)
return r;
}
hvc_instantiate(HVC_COOKIE, 0, ops);
return 0;
}
static DEFINE_XENBUS_DRIVER(xencons, "xenconsole",
.probe = xencons_probe,
.remove = xencons_remove,
.resume = xencons_resume,
.otherend_changed = xencons_backend_changed,
);
module_init(xen_hvc_init);
module_exit(xen_hvc_fini);
console_initcall(xen_cons_init);