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* [PATCH 08/14 v4] xen/arm: vpl011: Modify xenconsole to define and use a new console structure
@ 2017-06-06 10:03 Bhupinder Thakur
  0 siblings, 0 replies; 3+ messages in thread
From: Bhupinder Thakur @ 2017-06-06 10:03 UTC (permalink / raw)
  To: xen-devel; +Cc: Wei Liu, Julien Grall, Stefano Stabellini, Ian Jackson

Xenconsole uses a domain structure which contains console specific fields. This
patch defines a new console structure, which would be used by the xenconsole
functions to perform console specific operations like reading/writing data from/to
the console ring buffer or reading/writing data from/to console tty.

This patch is in preparation to support multiple consoles to support vuart console.

Signed-off-by: Bhupinder Thakur <bhupinder.thakur@linaro.org>
---

Changes since v3:
- The changes in xenconsole have been split into four patches. This is the first patch
  which modifies the xenconsole to use a new console structure.

Changes since v2:
- Defined a new function console_create_ring() which sets up the ring buffer and 
  event channel a new console. domain_create_ring() uses this function to setup
  a console.
- This patch does not contain vuart specific changes, which would be introduced in
  the next patch.
- Changes for keeping the PV log file name unchanged.

Changes since v1:
- Split the domain struture to a separate console structure
- Modified the functions to operate on the console struture
- Replaced repetitive per console code with generic code

 tools/console/daemon/io.c | 226 ++++++++++++++++++++++++++--------------------
 1 file changed, 127 insertions(+), 99 deletions(-)

diff --git a/tools/console/daemon/io.c b/tools/console/daemon/io.c
index 947f13a..0402ddf 100644
--- a/tools/console/daemon/io.c
+++ b/tools/console/daemon/io.c
@@ -89,25 +89,30 @@ struct buffer {
 	size_t max_capacity;
 };
 
-struct domain {
-	int domid;
+struct console {
 	int master_fd;
 	int master_pollfd_idx;
 	int slave_fd;
 	int log_fd;
-	bool is_dead;
-	unsigned last_seen;
 	struct buffer buffer;
-	struct domain *next;
 	char *conspath;
 	int ring_ref;
 	xenevtchn_port_or_error_t local_port;
 	xenevtchn_port_or_error_t remote_port;
+	struct xencons_interface *interface;
+	struct domain *d;
+};
+
+struct domain {
+	int domid;
+	bool is_dead;
+	unsigned last_seen;
+	struct domain *next;
 	xenevtchn_handle *xce_handle;
 	int xce_pollfd_idx;
-	struct xencons_interface *interface;
 	int event_count;
 	long long next_period;
+	struct console console;
 };
 
 static struct domain *dom_head;
@@ -160,9 +165,10 @@ static int write_with_timestamp(int fd, const char *data, size_t sz,
 
 static void buffer_append(struct domain *dom)
 {
-	struct buffer *buffer = &dom->buffer;
+	struct console *con = &dom->console;
+	struct buffer *buffer = &con->buffer;
 	XENCONS_RING_IDX cons, prod, size;
-	struct xencons_interface *intf = dom->interface;
+	struct xencons_interface *intf = con->interface;
 
 	cons = intf->out_cons;
 	prod = intf->out_prod;
@@ -187,22 +193,22 @@ static void buffer_append(struct domain *dom)
 
 	xen_mb();
 	intf->out_cons = cons;
-	xenevtchn_notify(dom->xce_handle, dom->local_port);
+	xenevtchn_notify(dom->xce_handle, con->local_port);
 
 	/* Get the data to the logfile as early as possible because if
 	 * no one is listening on the console pty then it will fill up
 	 * and handle_tty_write will stop being called.
 	 */
-	if (dom->log_fd != -1) {
+	if (con->log_fd != -1) {
 		int logret;
 		if (log_time_guest) {
 			logret = write_with_timestamp(
-				dom->log_fd,
+				con->log_fd,
 				buffer->data + buffer->size - size,
 				size, &log_time_guest_needts);
 		} else {
 			logret = write_all(
-				dom->log_fd,
+				con->log_fd,
 				buffer->data + buffer->size - size,
 				size);
 		}
@@ -338,14 +344,16 @@ static int create_domain_log(struct domain *dom)
 
 static void domain_close_tty(struct domain *dom)
 {
-	if (dom->master_fd != -1) {
-		close(dom->master_fd);
-		dom->master_fd = -1;
+	struct console *con = &dom->console;
+
+	if (con->master_fd != -1) {
+		close(con->master_fd);
+		con->master_fd = -1;
 	}
 
-	if (dom->slave_fd != -1) {
-		close(dom->slave_fd);
-		dom->slave_fd = -1;
+	if (con->slave_fd != -1) {
+		close(con->slave_fd);
+		con->slave_fd = -1;
 	}
 }
 
@@ -418,11 +426,12 @@ static int domain_create_tty(struct domain *dom)
 	char *data;
 	unsigned int len;
 	struct termios term;
+	struct console *con = &dom->console;
 
-	assert(dom->slave_fd == -1);
-	assert(dom->master_fd == -1);
+	assert(con->slave_fd == -1);
+	assert(con->master_fd == -1);
 
-	if (openpty(&dom->master_fd, &dom->slave_fd, NULL, NULL, NULL) < 0) {
+	if (openpty(&con->master_fd, &con->slave_fd, NULL, NULL, NULL) < 0) {
 		err = errno;
 		dolog(LOG_ERR, "Failed to create tty for domain-%d "
 		      "(errno = %i, %s)",
@@ -430,7 +439,7 @@ static int domain_create_tty(struct domain *dom)
 		return 0;
 	}
 
-	if (tcgetattr(dom->slave_fd, &term) < 0) {
+	if (tcgetattr(con->slave_fd, &term) < 0) {
 		err = errno;
 		dolog(LOG_ERR, "Failed to get tty attributes for domain-%d "
 			"(errno = %i, %s)",
@@ -438,7 +447,7 @@ static int domain_create_tty(struct domain *dom)
 		goto out;
 	}
 	cfmakeraw(&term);
-	if (tcsetattr(dom->slave_fd, TCSANOW, &term) < 0) {
+	if (tcsetattr(con->slave_fd, TCSANOW, &term) < 0) {
 		err = errno;
 		dolog(LOG_ERR, "Failed to set tty attributes for domain-%d "
 			"(errno = %i, %s)",
@@ -446,7 +455,7 @@ static int domain_create_tty(struct domain *dom)
 		goto out;
 	}
 
-	if ((slave = ptsname(dom->master_fd)) == NULL) {
+	if ((slave = ptsname(con->master_fd)) == NULL) {
 		err = errno;
 		dolog(LOG_ERR, "Failed to get slave name for domain-%d "
 		      "(errno = %i, %s)",
@@ -454,18 +463,18 @@ static int domain_create_tty(struct domain *dom)
 		goto out;
 	}
 
-	success = asprintf(&path, "%s/limit", dom->conspath) !=
+	success = asprintf(&path, "%s/limit", con->conspath) !=
 		-1;
 	if (!success)
 		goto out;
 	data = xs_read(xs, XBT_NULL, path, &len);
 	if (data) {
-		dom->buffer.max_capacity = strtoul(data, 0, 0);
+		con->buffer.max_capacity = strtoul(data, 0, 0);
 		free(data);
 	}
 	free(path);
 
-	success = (asprintf(&path, "%s/tty", dom->conspath) != -1);
+	success = (asprintf(&path, "%s/tty", con->conspath) != -1);
 	if (!success)
 		goto out;
 	success = xs_write(xs, XBT_NULL, path, slave, strlen(slave));
@@ -473,7 +482,7 @@ static int domain_create_tty(struct domain *dom)
 	if (!success)
 		goto out;
 
-	if (fcntl(dom->master_fd, F_SETFL, O_NONBLOCK) == -1)
+	if (fcntl(con->master_fd, F_SETFL, O_NONBLOCK) == -1)
 		goto out;
 
 	return 1;
@@ -519,29 +528,32 @@ static int xs_gather(struct xs_handle *xs, const char *dir, ...)
 
 static void domain_unmap_interface(struct domain *dom)
 {
-	if (dom->interface == NULL)
+	struct console *con = &dom->console;
+
+	if (con->interface == NULL)
 		return;
-	if (xgt_handle && dom->ring_ref == -1)
-		xengnttab_unmap(xgt_handle, dom->interface, 1);
+	if (xgt_handle && con->ring_ref == -1)
+		xengnttab_unmap(xgt_handle, con->interface, 1);
 	else
-		munmap(dom->interface, XC_PAGE_SIZE);
-	dom->interface = NULL;
-	dom->ring_ref = -1;
+		munmap(con->interface, XC_PAGE_SIZE);
+	con->interface = NULL;
+	con->ring_ref = -1;
 }
  
 static int domain_create_ring(struct domain *dom)
 {
 	int err, remote_port, ring_ref, rc;
 	char *type, path[PATH_MAX];
+	struct console *con = &dom->console;
 
-	err = xs_gather(xs, dom->conspath,
+	err = xs_gather(xs, con->conspath,
 			"ring-ref", "%u", &ring_ref,
 			"port", "%i", &remote_port,
 			NULL);
 	if (err)
 		goto out;
 
-	snprintf(path, sizeof(path), "%s/type", dom->conspath);
+	snprintf(path, sizeof(path), "%s/type", con->conspath);
 	type = xs_read(xs, XBT_NULL, path, NULL);
 	if (type && strcmp(type, "xenconsoled") != 0) {
 		free(type);
@@ -550,41 +562,41 @@ static int domain_create_ring(struct domain *dom)
 	free(type);
 
 	/* If using ring_ref and it has changed, remap */
-	if (ring_ref != dom->ring_ref && dom->ring_ref != -1)
+	if (ring_ref != con->ring_ref && con->ring_ref != -1)
 		domain_unmap_interface(dom);
 
-	if (!dom->interface && xgt_handle) {
+	if (!con->interface && xgt_handle) {
 		/* Prefer using grant table */
-		dom->interface = xengnttab_map_grant_ref(xgt_handle,
+		con->interface = xengnttab_map_grant_ref(xgt_handle,
 			dom->domid, GNTTAB_RESERVED_CONSOLE,
 			PROT_READ|PROT_WRITE);
-		dom->ring_ref = -1;
+		con->ring_ref = -1;
 	}
-	if (!dom->interface) {
+	if (!con->interface) {
 		/* Fall back to xc_map_foreign_range */
-		dom->interface = xc_map_foreign_range(
+		con->interface = xc_map_foreign_range(
 			xc, dom->domid, XC_PAGE_SIZE,
 			PROT_READ|PROT_WRITE,
 			(unsigned long)ring_ref);
-		if (dom->interface == NULL) {
+		if (con->interface == NULL) {
 			err = EINVAL;
 			goto out;
 		}
-		dom->ring_ref = ring_ref;
+		con->ring_ref = ring_ref;
 	}
 
 	/* Go no further if port has not changed and we are still bound. */
-	if (remote_port == dom->remote_port) {
+	if (remote_port == con->remote_port) {
 		xc_evtchn_status_t status = {
 			.dom = DOMID_SELF,
-			.port = dom->local_port };
+			.port = con->local_port };
 		if ((xc_evtchn_status(xc, &status) == 0) &&
 		    (status.status == EVTCHNSTAT_interdomain))
 			goto out;
 	}
 
-	dom->local_port = -1;
-	dom->remote_port = -1;
+	con->local_port = -1;
+	con->remote_port = -1;
 	if (dom->xce_handle != NULL)
 		xenevtchn_close(dom->xce_handle);
 
@@ -605,22 +617,22 @@ static int domain_create_ring(struct domain *dom)
 		dom->xce_handle = NULL;
 		goto out;
 	}
-	dom->local_port = rc;
-	dom->remote_port = remote_port;
+	con->local_port = rc;
+	con->remote_port = remote_port;
 
-	if (dom->master_fd == -1) {
+	if (con->master_fd == -1) {
 		if (!domain_create_tty(dom)) {
 			err = errno;
 			xenevtchn_close(dom->xce_handle);
 			dom->xce_handle = NULL;
-			dom->local_port = -1;
-			dom->remote_port = -1;
+			con->local_port = -1;
+			con->remote_port = -1;
 			goto out;
 		}
 	}
 
-	if (log_guest && (dom->log_fd == -1))
-		dom->log_fd = create_domain_log(dom);
+	if (log_guest && (con->log_fd == -1))
+		con->log_fd = create_domain_log(dom);
 
  out:
 	return err;
@@ -630,16 +642,17 @@ static bool watch_domain(struct domain *dom, bool watch)
 {
 	char domid_str[3 + MAX_STRLEN(dom->domid)];
 	bool success;
+	struct console *con = &dom->console;
 
 	snprintf(domid_str, sizeof(domid_str), "dom%u", dom->domid);
 	if (watch) {
-		success = xs_watch(xs, dom->conspath, domid_str);
+		success = xs_watch(xs, con->conspath, domid_str);
 		if (success)
 			domain_create_ring(dom);
 		else
-			xs_unwatch(xs, dom->conspath, domid_str);
+			xs_unwatch(xs, con->conspath, domid_str);
 	} else {
-		success = xs_unwatch(xs, dom->conspath, domid_str);
+		success = xs_unwatch(xs, con->conspath, domid_str);
 	}
 
 	return success;
@@ -651,6 +664,7 @@ static struct domain *create_domain(int domid)
 	struct domain *dom;
 	char *s;
 	struct timespec ts;
+	struct console *con;
 
 	if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
 		dolog(LOG_ERR, "Cannot get time of day %s:%s:L%d",
@@ -667,25 +681,26 @@ static struct domain *create_domain(int domid)
 
 	dom->domid = domid;
 
-	dom->conspath = xs_get_domain_path(xs, dom->domid);
-	s = realloc(dom->conspath, strlen(dom->conspath) +
+	con = &dom->console;
+	con->conspath = xs_get_domain_path(xs, dom->domid);
+	s = realloc(con->conspath, strlen(con->conspath) +
 		    strlen("/console") + 1);
 	if (s == NULL)
 		goto out;
-	dom->conspath = s;
-	strcat(dom->conspath, "/console");
+	con->conspath = s;
+	strcat(con->conspath, "/console");
 
-	dom->master_fd = -1;
-	dom->master_pollfd_idx = -1;
-	dom->slave_fd = -1;
-	dom->log_fd = -1;
+	con->master_fd = -1;
+	con->master_pollfd_idx = -1;
+	con->slave_fd = -1;
+	con->log_fd = -1;
 	dom->xce_pollfd_idx = -1;
 
 	dom->next_period = ((long long)ts.tv_sec * 1000) + (ts.tv_nsec / 1000000) + RATE_LIMIT_PERIOD;
 
-	dom->ring_ref = -1;
-	dom->local_port = -1;
-	dom->remote_port = -1;
+	con->ring_ref = -1;
+	con->local_port = -1;
+	con->remote_port = -1;
 
 	if (!watch_domain(dom, true))
 		goto out;
@@ -697,7 +712,7 @@ static struct domain *create_domain(int domid)
 
 	return dom;
  out:
-	free(dom->conspath);
+	free(con->conspath);
 	free(dom);
 	return NULL;
 }
@@ -729,18 +744,20 @@ static void remove_domain(struct domain *dom)
 
 static void cleanup_domain(struct domain *d)
 {
+	struct console *con = &d->console;
+
 	domain_close_tty(d);
 
-	if (d->log_fd != -1) {
-		close(d->log_fd);
-		d->log_fd = -1;
+	if (con->log_fd != -1) {
+		close(con->log_fd);
+		con->log_fd = -1;
 	}
 
-	free(d->buffer.data);
-	d->buffer.data = NULL;
+	free(con->buffer.data);
+	con->buffer.data = NULL;
 
-	free(d->conspath);
-	d->conspath = NULL;
+	free(con->conspath);
+	con->conspath = NULL;
 
 	remove_domain(d);
 }
@@ -782,7 +799,8 @@ static void enum_domains(void)
 
 static int ring_free_bytes(struct domain *dom)
 {
-	struct xencons_interface *intf = dom->interface;
+	struct console *con = &dom->console;
+	struct xencons_interface *intf = con->interface;
 	XENCONS_RING_IDX cons, prod, space;
 
 	cons = intf->in_cons;
@@ -812,7 +830,8 @@ static void handle_tty_read(struct domain *dom)
 	ssize_t len = 0;
 	char msg[80];
 	int i;
-	struct xencons_interface *intf = dom->interface;
+	struct console *con = &dom->console;
+	struct xencons_interface *intf = con->interface;
 	XENCONS_RING_IDX prod;
 
 	if (dom->is_dead)
@@ -825,7 +844,7 @@ static void handle_tty_read(struct domain *dom)
 	if (len > sizeof(msg))
 		len = sizeof(msg);
 
-	len = read(dom->master_fd, msg, len);
+	len = read(con->master_fd, msg, len);
 	/*
 	 * Note: on Solaris, len == 0 means the slave closed, and this
 	 * is no problem, but Linux can't handle this usefully, so we
@@ -841,7 +860,7 @@ static void handle_tty_read(struct domain *dom)
 		}
 		xen_wmb();
 		intf->in_prod = prod;
-		xenevtchn_notify(dom->xce_handle, dom->local_port);
+		xenevtchn_notify(dom->xce_handle, con->local_port);
 	} else {
 		domain_close_tty(dom);
 		shutdown_domain(dom);
@@ -851,18 +870,19 @@ static void handle_tty_read(struct domain *dom)
 static void handle_tty_write(struct domain *dom)
 {
 	ssize_t len;
+	struct console *con = &dom->console;
 
 	if (dom->is_dead)
 		return;
 
-	len = write(dom->master_fd, dom->buffer.data + dom->buffer.consumed,
-		    dom->buffer.size - dom->buffer.consumed);
+	len = write(con->master_fd, con->buffer.data + con->buffer.consumed,
+		    con->buffer.size - con->buffer.consumed);
  	if (len < 1) {
 		dolog(LOG_DEBUG, "Write failed on domain %d: %zd, %d\n",
 		      dom->domid, len, errno);
 		domain_handle_broken_tty(dom, domain_is_valid(dom->domid));
 	} else {
-		buffer_advance(&dom->buffer, len);
+		buffer_advance(&con->buffer, len);
 	}
 }
 
@@ -948,9 +968,11 @@ static void handle_log_reload(void)
 	if (log_guest) {
 		struct domain *d;
 		for (d = dom_head; d; d = d->next) {
-			if (d->log_fd != -1)
-				close(d->log_fd);
-			d->log_fd = create_domain_log(d);
+			struct console *con = &d->console;
+
+			if (con->log_fd != -1)
+				close(con->log_fd);
+			con->log_fd = create_domain_log(d);
 		}
 	}
 
@@ -1059,6 +1081,8 @@ void handle_io(void)
 		/* Re-calculate any event counter allowances & unblock
 		   domains with new allowance */
 		for (d = dom_head; d; d = d->next) {
+			struct console *con = &d->console;
+
 			/* CS 16257:955ee4fa1345 introduces a 5ms fuzz
 			 * for select(), it is not clear poll() has
 			 * similar behavior (returning a couple of ms
@@ -1068,13 +1092,15 @@ void handle_io(void)
 			if ((now+5) > d->next_period) {
 				d->next_period = now + RATE_LIMIT_PERIOD;
 				if (d->event_count >= RATE_LIMIT_ALLOWANCE) {
-					(void)xenevtchn_unmask(d->xce_handle, d->local_port);
+					(void)xenevtchn_unmask(d->xce_handle, con->local_port);
 				}
 				d->event_count = 0;
 			}
 		}
 
 		for (d = dom_head; d; d = d->next) {
+			struct console *con = &d->console;
+
 			if (d->event_count >= RATE_LIMIT_ALLOWANCE) {
 				/* Determine if we're going to be the next time slice to expire */
 				if (!next_timeout ||
@@ -1082,25 +1108,25 @@ void handle_io(void)
 					next_timeout = d->next_period;
 			} else if (d->xce_handle != NULL) {
 				if (discard_overflowed_data ||
-				    !d->buffer.max_capacity ||
-				    d->buffer.size < d->buffer.max_capacity) {
+				    !con->buffer.max_capacity ||
+				    con->buffer.size < con->buffer.max_capacity) {
 					int evtchn_fd = xenevtchn_fd(d->xce_handle);
 					d->xce_pollfd_idx = set_fds(evtchn_fd,
 								    POLLIN|POLLPRI);
 				}
 			}
 
-			if (d->master_fd != -1) {
+			if (con->master_fd != -1) {
 				short events = 0;
 				if (!d->is_dead && ring_free_bytes(d))
 					events |= POLLIN;
 
-				if (!buffer_empty(&d->buffer))
+				if (!buffer_empty(&con->buffer))
 					events |= POLLOUT;
 
 				if (events)
-					d->master_pollfd_idx =
-						set_fds(d->master_fd,
+					con->master_pollfd_idx =
+						set_fds(con->master_fd,
 							events|POLLPRI);
 			}
 		}
@@ -1159,6 +1185,8 @@ void handle_io(void)
 		}
 
 		for (d = dom_head; d; d = n) {
+			struct console *con = &d->console;
+
 			n = d->next;
 			if (d->event_count < RATE_LIMIT_ALLOWANCE) {
 				if (d->xce_handle != NULL &&
@@ -1170,22 +1198,22 @@ void handle_io(void)
 				    handle_ring_read(d);
 			}
 
-			if (d->master_fd != -1 && d->master_pollfd_idx != -1) {
-				if (fds[d->master_pollfd_idx].revents &
+			if (con->master_fd != -1 && con->master_pollfd_idx != -1) {
+				if (fds[con->master_pollfd_idx].revents &
 				    ~(POLLIN|POLLOUT|POLLPRI))
 					domain_handle_broken_tty(d,
 						   domain_is_valid(d->domid));
 				else {
-					if (fds[d->master_pollfd_idx].revents &
+					if (fds[con->master_pollfd_idx].revents &
 					    POLLIN)
 						handle_tty_read(d);
-					if (fds[d->master_pollfd_idx].revents &
+					if (fds[con->master_pollfd_idx].revents &
 					    POLLOUT)
 						handle_tty_write(d);
 				}
 			}
 
-			d->xce_pollfd_idx = d->master_pollfd_idx = -1;
+			d->xce_pollfd_idx = con->master_pollfd_idx = -1;
 
 			if (d->last_seen != enum_pass)
 				shutdown_domain(d);
-- 
2.7.4


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^ permalink raw reply related	[flat|nested] 3+ messages in thread
* [PATCH 00/14 v4] PL011 emulation support in Xen
@ 2017-06-06 17:25 Bhupinder Thakur
  2017-06-06 17:25 ` [PATCH 08/14 v4] xen/arm: vpl011: Modify xenconsole to define and use a new console structure Bhupinder Thakur
  0 siblings, 1 reply; 3+ messages in thread
From: Bhupinder Thakur @ 2017-06-06 17:25 UTC (permalink / raw)
  To: xen-devel; +Cc: Wei Liu, Julien Grall, Stefano Stabellini, Ian Jackson

PL011 emulation for guests in Xen
===================================
Linaro has published VM System specification for ARM Processors, which
provides a set of guidelines for both guest OS and hypervisor implementations, 
such that building OS images according to these guidelines guarantees
that those images can also run on hypervisors compliant with this specification.

One of the spec requirements is that the hypervisor must provide an
emulated PL011 UART as a serial console which meets the minimum requirements in 
SBSA UART as defined in appendix B of the following 
ARM Server Base Architecture Document:

https://static.docs.arm.com/den0029/a/Server_Base_System_Architecture_v3_1_ARM_DEN_0029A.pdf.

This feature allows the Xen guests to use SBSA compliant pl011 UART as 
as a console. 

Note that SBSA pl011 UART is a subset of full featured ARM pl011 UART and
supports only a subset of registers as mentioned below. It does not support
rx/tx DMA.

Currently, Xen supports paravirtualized (aka PV console) and an emulated serial 
consoles. This feature will expose an emulated SBSA pl011 UART console to the
guest, which a user can access using xenconsole.

The device tree passed to the guest VM will contain the pl011 MMIO address 
range and an irq for receiving rx/tx pl011 interrupts. The device tree format 
is specified in Documentation/devicetree/bindings/serial/arm_sbsa_uart.txt.

The Xen hypervisor will expose two types of interfaces to the backend and domU. 

The interface exposed to domU will be an emulated pl011 UART by emulating the 
access to the following pl011 registers by the guest.

- Data register (DR)            - RW
- Raw interrupt status register (RIS)   - RO
- Masked interrupt status register (MIS)- RO
- Interrupt Mask (IMSC)         - RW
- Interrupt Clear (ICR)         - WO

It will also inject the pl011 interrupts to the guest in the following 
conditions:

- incoming data in the rx buffer for the guest
- there is space in the tx buffer for the guest to write more data

The interface exposed to the backend will be the same PV console interface, 
which minimizes the changes required in xenconsole to support a new pl011 console.

This interface has rx and tx ring buffers and an event channel for 
sending/receiving events from the backend. 

So essentially Xen handles the data on behalf of domU and the backend. Any data 
written by domU is captured by Xen and written to the TX (OUT) ring buffer 
and a pl011 event is raised to the backend to read the TX ring buffer.
 
Similarly on reciving a pl011 event, Xen injects an interrupt to guest to
indicate there is data available in the RX (IN) ring buffer.

The pl011 UART state is completely captured in the set of registers 
mentioned above and this state is updated everytime there is an event from 
the backend or there is register read/write access from domU. 

For example, if domU has masked the rx interrupt in the IMSC register, then Xen 
will not inject an interrupt to guest and will just update the RIS register. 
Once the interrupt is unmasked by guest, the interrupt will be delivered to the 
guest.

Changes summary:

Xen Hypervisor
===============

1. Add emulation code to emulate read/write access to pl011 registers and pl011 
   interrupts:
    - It emulates DR read/write by reading and writing from/to the IN and 
      OUT ring buffers and raising an event to dom0 when there is data in 
      the OUT ring buffer and injecting an interrupt to the guest when there 
      is data in the IN ring buffer.
    - Other registers are related to interrupt management and essentially 
      control when interrupts are delivered to the guest.

2. Add a new domctl API to initialize vpl011 emulation in Xen.

3. Enable vpl011 emulation for a domain based on a libxl option passed during 
   domain creation.

Toolstack
==========

1. Add a new option "vuart" in the domU configuration file to enable/disable vuart.

2. Create a SBSA UART DT node in the guest device tree. It uses a fixed
   vpl011 SPI IRQ number and MMIO address.

3. Call vpl011 init DOMCTL API to enable vpl011 emulation.

5. Add a new vuart xenstore node, which contains:
    - ring-ref
    - event channel
    - buffer limit
    - type

Xenconsoled
============

1. Split the domain structure to support multiple consoles.

2. Modify different APIs such as buffer_append() etc. to operate on the 
   console structure.
   
3. Add support for handling multiple consoles.

4. Add support for vuart console:

The vpl011 changes available at the following repo:

url: ssh://git@git.linaro.org:/people/bhupinder.thakur/xen.git
branch: vpl011_v4

There are some TBD items which need to be looked at in the future:

1. Currently UEFI firmware logs the output to hvc console only. How can 
   UEFI firmware be made aware of pl011 console and how it can use it
   as a console instead of hvc.
2. Linux seems to have hvc console as the default console i.e. if no
   console is specified then it uses hvc as the console. How can an 
   option be provided in Linux to select either hvc or pl011 as the 
   default console.

3. ACPI support for pl011 device.

CC: ij
CC: wl
CC: ss
CC: jg
CC: kw

Bhupinder Thakur (14):
  xen/arm: vpl011: Move vgic register access functions to vreg.h
  xen/arm: vpl011: Define generic vreg_reg* access functions in vreg.h
  xen/arm: vpl011: Add pl011 uart emulation in Xen
  xen/arm: vpl011: Add support for vuart in libxl
  xen/arm: vpl011: Allocate a new GFN in the toolstack for vuart
  xen/arm: vpl011: Add a new domctl API to initialize vpl011
  xen/arm: vpl011: Add a new vuart node in the xenstore
  xen/arm: vpl011: Modify xenconsole to define and use a new console    
    structure
  xen/arm: vpl011: Modify xenconsole functions to take console structure
    as input
  xen/arm: vpl011: Modify xenconsole to support multiple consoles
  xen/arm: vpl011: Add support for vuart console in xenconsole
  xen/arm: vpl011: Add a new vuart console type to xenconsole client
  xen/arm: vpl011: Add a pl011 uart DT node in the guest device tree
  xen/arm: vpl011: Update documentation for vuart console support

 config/arm32.mk                      |   1 +
 config/arm64.mk                      |   1 +
 docs/man/xl.cfg.pod.5.in             |   9 +
 docs/misc/console.txt                |  44 ++-
 tools/console/Makefile               |   4 +-
 tools/console/client/main.c          |  25 +-
 tools/console/daemon/io.c            | 544 ++++++++++++++++++++++++-----------
 tools/libxc/include/xc_dom.h         |   3 +
 tools/libxc/include/xenctrl.h        |  17 ++
 tools/libxc/xc_dom_arm.c             |  12 +-
 tools/libxc/xc_dom_boot.c            |   2 +
 tools/libxc/xc_domain.c              |  23 ++
 tools/libxl/libxl.h                  |   6 +
 tools/libxl/libxl_arch.h             |   7 +
 tools/libxl/libxl_arm.c              |  71 ++++-
 tools/libxl/libxl_console.c          |  47 +++
 tools/libxl/libxl_create.c           |  12 +-
 tools/libxl/libxl_device.c           |   9 +-
 tools/libxl/libxl_dom.c              |   8 +-
 tools/libxl/libxl_internal.h         |   7 +
 tools/libxl/libxl_types.idl          |   7 +
 tools/libxl/libxl_types_internal.idl |   1 +
 tools/libxl/libxl_x86.c              |   8 +
 tools/xl/Makefile                    |   4 +
 tools/xl/xl_cmdtable.c               |   4 +
 tools/xl/xl_console.c                |  11 +-
 tools/xl/xl_parse.c                  |   8 +
 xen/arch/arm/Kconfig                 |   5 +
 xen/arch/arm/Makefile                |   1 +
 xen/arch/arm/domain.c                |   2 +
 xen/arch/arm/domctl.c                |  44 ++-
 xen/arch/arm/vgic-v2.c               |  28 +-
 xen/arch/arm/vgic-v3.c               |  40 +--
 xen/arch/arm/vpl011.c                | 418 +++++++++++++++++++++++++++
 xen/include/asm-arm/domain.h         |   6 +
 xen/include/asm-arm/pl011-uart.h     |   2 +
 xen/include/asm-arm/vgic.h           | 111 +------
 xen/include/asm-arm/vpl011.h         |  74 +++++
 xen/include/asm-arm/vreg.h           | 109 +++++++
 xen/include/public/arch-arm.h        |   6 +
 xen/include/public/domctl.h          |  12 +
 xen/include/public/io/console.h      |   4 +
 42 files changed, 1421 insertions(+), 336 deletions(-)
 create mode 100644 xen/arch/arm/vpl011.c
 create mode 100644 xen/include/asm-arm/vpl011.h

-- 
2.7.4


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2017-06-06 10:03 [PATCH 08/14 v4] xen/arm: vpl011: Modify xenconsole to define and use a new console structure Bhupinder Thakur
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2017-06-06 17:25 [PATCH 00/14 v4] PL011 emulation support in Xen Bhupinder Thakur
2017-06-06 17:25 ` [PATCH 08/14 v4] xen/arm: vpl011: Modify xenconsole to define and use a new console structure Bhupinder Thakur
2017-06-07  1:13   ` Stefano Stabellini

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