Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 771 insertions, 0 deletions

diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
new file mode 100644
index 0000000000..34c01874f4
--- /dev/null
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -0,0 +1,771 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * xen console driver interface to hvc_console.c
+ *
+ * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
+ */
+
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/irq.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/serial_core.h>
+
+#include <asm/io.h>
+#include <asm/xen/hypervisor.h>
+
+#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/interface/sched.h>
+#include <xen/hvc-console.h>
+#include <xen/xenbus.h>
+
+#include "hvc_console.h"
+
+#define HVC_COOKIE   0x58656e /* "Xen" in hex */
+
+struct xencons_info {
+	struct list_head list;
+	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;
+	grant_ref_t gntref;
+	spinlock_t ring_lock;
+};
+
+static LIST_HEAD(xenconsoles);
+static DEFINE_SPINLOCK(xencons_lock);
+
+/* ------------------------------------------------------------------ */
+
+static struct xencons_info *vtermno_to_xencons(int vtermno)
+{
+	struct xencons_info *entry, *ret = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&xencons_lock, flags);
+	if (list_empty(&xenconsoles)) {
+		spin_unlock_irqrestore(&xencons_lock, flags);
+		return NULL;
+	}
+
+	list_for_each_entry(entry, &xenconsoles, list) {
+		if (entry->vtermno == vtermno) {
+			ret  = entry;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&xencons_lock, flags);
+
+	return ret;
+}
+
+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. */
+	notify_remote_via_evtchn(cons->evtchn);
+}
+
+static int __write_console(struct xencons_info *xencons,
+		const char *data, int len)
+{
+	XENCONS_RING_IDX cons, prod;
+	struct xencons_interface *intf = xencons->intf;
+	int sent = 0;
+	unsigned long flags;
+
+	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;
+	}
+
+	while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
+		intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
+
+	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)
+{
+	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
+	 * necessary.  We don't ever want to rely on the hvc daemon
+	 * because the most interesting console output is when the
+	 * kernel is crippled.
+	 */
+	while (len) {
+		int sent = __write_console(cons, data, len);
+
+		if (sent < 0)
+			return sent;
+
+		data += sent;
+		len -= sent;
+
+		if (unlikely(len))
+			HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
+	}
+
+	return ret;
+}
+
+static int domU_read_console(uint32_t vtermno, char *buf, int 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;
+
+	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;
+	}
+
+	while (cons != prod && recv < len)
+		buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
+
+	mb();			/* read ring before consuming */
+	intf->in_cons = cons;
+
+	/*
+	 * 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 && xencons->out_cons_same++ > 1) {
+		eoiflag = XEN_EOI_FLAG_SPURIOUS;
+	}
+	spin_unlock_irqrestore(&xencons->ring_lock, flags);
+
+	if (recv) {
+		notify_daemon(xencons);
+	}
+
+	xen_irq_lateeoi(xencons->irq, eoiflag);
+
+	return recv;
+}
+
+static const struct hv_ops domU_hvc_ops = {
+	.get_chars = domU_read_console,
+	.put_chars = domU_write_console,
+	.notifier_add = notifier_add_irq,
+	.notifier_del = notifier_del_irq,
+	.notifier_hangup = notifier_hangup_irq,
+};
+
+static int dom0_read_console(uint32_t vtermno, char *buf, int len)
+{
+	return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
+}
+
+/*
+ * 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)
+{
+	int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
+	if (rc < 0)
+		return rc;
+
+	return len;
+}
+
+static const struct hv_ops dom0_hvc_ops = {
+	.get_chars = dom0_read_console,
+	.put_chars = dom0_write_console,
+	.notifier_add = notifier_add_irq,
+	.notifier_del = notifier_del_irq,
+	.notifier_hangup = notifier_hangup_irq,
+};
+
+static int xen_hvm_console_init(void)
+{
+	int r;
+	uint64_t v = 0;
+	unsigned long gfn, flags;
+	struct xencons_info *info;
+
+	if (!xen_hvm_domain())
+		return -ENODEV;
+
+	info = vtermno_to_xencons(HVC_COOKIE);
+	if (!info) {
+		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;
+	}
+	/*
+	 * If the toolstack (or the hypervisor) hasn't set these values, the
+	 * default value is 0. Even though gfn = 0 and evtchn = 0 are
+	 * theoretically correct values, in practice they never are and they
+	 * mean that a legacy toolstack hasn't initialized the pv console correctly.
+	 */
+	r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
+	if (r < 0 || v == 0)
+		goto err;
+	info->evtchn = v;
+	v = 0;
+	r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
+	if (r < 0 || v == 0)
+		goto err;
+	gfn = v;
+	info->intf = memremap(gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE, MEMREMAP_WB);
+	if (info->intf == NULL)
+		goto err;
+	info->vtermno = HVC_COOKIE;
+
+	spin_lock_irqsave(&xencons_lock, flags);
+	list_add_tail(&info->list, &xenconsoles);
+	spin_unlock_irqrestore(&xencons_lock, flags);
+
+	return 0;
+err:
+	kfree(info);
+	return -ENODEV;
+}
+
+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);
+	info->vtermno = vtermno;
+
+	list_add_tail(&info->list, &xenconsoles);
+
+	return 0;
+}
+
+static int xen_pv_console_init(void)
+{
+	struct xencons_info *info;
+	unsigned long flags;
+
+	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);
+		if (!info)
+			return -ENOMEM;
+	} else if (info->intf != NULL) {
+		/* already configured */
+		return 0;
+	}
+	spin_lock_irqsave(&xencons_lock, flags);
+	xencons_info_pv_init(info, HVC_COOKIE);
+	spin_unlock_irqrestore(&xencons_lock, flags);
+
+	return 0;
+}
+
+static int xen_initial_domain_console_init(void)
+{
+	struct xencons_info *info;
+	unsigned long flags;
+
+	if (!xen_initial_domain())
+		return -ENODEV;
+
+	info = vtermno_to_xencons(HVC_COOKIE);
+	if (!info) {
+		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);
+	info->vtermno = HVC_COOKIE;
+
+	spin_lock_irqsave(&xencons_lock, flags);
+	list_add_tail(&info->list, &xenconsoles);
+	spin_unlock_irqrestore(&xencons_lock, flags);
+
+	return 0;
+}
+
+static void xen_console_update_evtchn(struct xencons_info *info)
+{
+	if (xen_hvm_domain()) {
+		uint64_t v = 0;
+		int err;
+
+		err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
+		if (!err && v)
+			info->evtchn = v;
+	} else
+		info->evtchn = xen_start_info->console.domU.evtchn;
+}
+
+void xen_console_resume(void)
+{
+	struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
+	if (info != NULL && info->irq) {
+		if (!xen_initial_domain())
+			xen_console_update_evtchn(info);
+		rebind_evtchn_irq(info->evtchn, info->irq);
+	}
+}
+
+#ifdef CONFIG_HVC_XEN_FRONTEND
+static void xencons_disconnect_backend(struct xencons_info *info)
+{
+	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;
+}
+
+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)
+{
+	unsigned long flags;
+
+	xencons_disconnect_backend(info);
+	spin_lock_irqsave(&xencons_lock, flags);
+	list_del(&info->list);
+	spin_unlock_irqrestore(&xencons_lock, flags);
+	if (info->xbdev != NULL)
+		xencons_free(info);
+	else {
+		if (xen_hvm_domain())
+			iounmap(info->intf);
+		kfree(info);
+	}
+	return 0;
+}
+
+static void xencons_remove(struct xenbus_device *dev)
+{
+	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;
+
+	ret = xenbus_alloc_evtchn(dev, &evtchn);
+	if (ret)
+		return ret;
+	info->evtchn = evtchn;
+	irq = bind_evtchn_to_irq_lateeoi(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);
+	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,
+					virt_to_gfn(info->intf), 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_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 xencons_probe(struct xenbus_device *dev,
+				  const struct xenbus_device_id *id)
+{
+	int ret, devid;
+	struct xencons_info *info;
+	unsigned long flags;
+
+	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
+	if (devid == 0)
+		return -ENODEV;
+
+	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);
+	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_irqsave(&xencons_lock, flags);
+	list_add_tail(&info->list, &xenconsoles);
+	spin_unlock_irqrestore(&xencons_lock, flags);
+
+	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, XEN_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:
+		break;
+
+	case XenbusStateInitWait:
+		break;
+
+	case XenbusStateConnected:
+		xenbus_switch_state(dev, XenbusStateConnected);
+		break;
+
+	case XenbusStateClosed:
+		if (dev->state == XenbusStateClosed)
+			break;
+		fallthrough;	/* Missed the backend's CLOSING state */
+	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[] = {
+	{ "console" },
+	{ "" }
+};
+
+static struct xenbus_driver xencons_driver = {
+	.name = "xenconsole",
+	.ids = xencons_ids,
+	.probe = xencons_probe,
+	.remove = xencons_remove,
+	.resume = xencons_resume,
+	.otherend_changed = xencons_backend_changed,
+	.not_essential = true,
+};
+#endif /* CONFIG_HVC_XEN_FRONTEND */
+
+static int __init xen_hvc_init(void)
+{
+	int r;
+	struct xencons_info *info;
+	const struct hv_ops *ops;
+
+	if (!xen_domain())
+		return -ENODEV;
+
+	if (xen_initial_domain()) {
+		ops = &dom0_hvc_ops;
+		r = xen_initial_domain_console_init();
+		if (r < 0)
+			goto register_fe;
+		info = vtermno_to_xencons(HVC_COOKIE);
+	} else {
+		ops = &domU_hvc_ops;
+		if (xen_hvm_domain())
+			r = xen_hvm_console_init();
+		else
+			r = xen_pv_console_init();
+		if (r < 0)
+			goto register_fe;
+
+		info = vtermno_to_xencons(HVC_COOKIE);
+		info->irq = bind_evtchn_to_irq_lateeoi(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)) {
+		unsigned long flags;
+
+		r = PTR_ERR(info->hvc);
+		spin_lock_irqsave(&xencons_lock, flags);
+		list_del(&info->list);
+		spin_unlock_irqrestore(&xencons_lock, flags);
+		if (info->irq)
+			evtchn_put(info->evtchn);
+		kfree(info);
+		return r;
+	}
+
+	r = 0;
+ register_fe:
+#ifdef CONFIG_HVC_XEN_FRONTEND
+	r = xenbus_register_frontend(&xencons_driver);
+#endif
+	return r;
+}
+device_initcall(xen_hvc_init);
+
+static int xen_cons_init(void)
+{
+	const struct hv_ops *ops;
+
+	if (!xen_domain())
+		return 0;
+
+	if (xen_initial_domain())
+		ops = &dom0_hvc_ops;
+	else {
+		int r;
+		ops = &domU_hvc_ops;
+
+		if (xen_hvm_domain())
+			r = xen_hvm_console_init();
+		else
+			r = xen_pv_console_init();
+		if (r < 0)
+			return r;
+	}
+
+	hvc_instantiate(HVC_COOKIE, 0, ops);
+	return 0;
+}
+console_initcall(xen_cons_init);
+
+#ifdef CONFIG_X86
+static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len)
+{
+	if (xen_cpuid_base())
+		outsb(0xe9, str, len);
+}
+#else
+static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) { }
+#endif
+
+#ifdef CONFIG_EARLY_PRINTK
+static int __init xenboot_console_setup(struct console *console, char *string)
+{
+	static struct xencons_info xenboot;
+
+	if (xen_initial_domain() || !xen_pv_domain())
+		return 0;
+
+	return xencons_info_pv_init(&xenboot, 0);
+}
+
+static void xenboot_write_console(struct console *console, const char *string,
+				  unsigned len)
+{
+	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;
+	}
+
+	if (domU_write_console(0, "(early) ", 8) < 0)
+		return;
+	while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
+		linelen = pos-string+off;
+		if (off + linelen > len)
+			break;
+		domU_write_console(0, string+off, linelen);
+		domU_write_console(0, "\r\n", 2);
+		off += linelen + 1;
+	}
+	if (off < len)
+		domU_write_console(0, string+off, len-off);
+}
+
+struct console xenboot_console = {
+	.name		= "xenboot",
+	.write		= xenboot_write_console,
+	.setup		= xenboot_console_setup,
+	.flags		= CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
+	.index		= -1,
+};
+#endif	/* CONFIG_EARLY_PRINTK */
+
+void xen_raw_console_write(const char *str)
+{
+	ssize_t len = strlen(str);
+	int rc = 0;
+
+	if (xen_domain()) {
+		rc = dom0_write_console(0, str, len);
+		if (rc != -ENOSYS || !xen_hvm_domain())
+			return;
+	}
+	xen_hvm_early_write(0, str, len);
+}
+
+void xen_raw_printk(const char *fmt, ...)
+{
+	static char buf[512];
+	va_list ap;
+
+	va_start(ap, fmt);
+	vsnprintf(buf, sizeof(buf), fmt, ap);
+	va_end(ap);
+
+	xen_raw_console_write(buf);
+}
+
+static void xenboot_earlycon_write(struct console *console,
+				  const char *string,
+				  unsigned len)
+{
+	dom0_write_console(0, string, len);
+}
+
+static int __init xenboot_earlycon_setup(struct earlycon_device *device,
+					    const char *opt)
+{
+	device->con->write = xenboot_earlycon_write;
+	return 0;
+}
+EARLYCON_DECLARE(xenboot, xenboot_earlycon_setup);