qemu-e2k/hw/char/xen_console.c

295 lines
8.2 KiB
C
Raw Normal View History

/*
* Copyright (C) International Business Machines Corp., 2005
* Author(s): Anthony Liguori <aliguori@us.ibm.com>
*
* Copyright (C) Red Hat 2007
*
* Xen Console
*
* 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; under version 2 of the License.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include <sys/select.h>
#include <termios.h>
#include "qapi/error.h"
#include "hw/hw.h"
#include "chardev/char-fe.h"
#include "hw/xen/xen_backend.h"
#include <xen/io/console.h>
struct buffer {
uint8_t *data;
size_t consumed;
size_t size;
size_t capacity;
size_t max_capacity;
};
struct XenConsole {
struct XenDevice xendev; /* must be first */
struct buffer buffer;
char console[XEN_BUFSIZE];
int ring_ref;
void *sring;
CharBackend chr;
int backlog;
};
static void buffer_append(struct XenConsole *con)
{
struct buffer *buffer = &con->buffer;
XENCONS_RING_IDX cons, prod, size;
struct xencons_interface *intf = con->sring;
cons = intf->out_cons;
prod = intf->out_prod;
xen_mb();
size = prod - cons;
if ((size == 0) || (size > sizeof(intf->out)))
return;
if ((buffer->capacity - buffer->size) < size) {
buffer->capacity += (size + 1024);
buffer->data = g_realloc(buffer->data, buffer->capacity);
}
while (cons != prod)
buffer->data[buffer->size++] = intf->out[
MASK_XENCONS_IDX(cons++, intf->out)];
xen_mb();
intf->out_cons = cons;
xen_pv_send_notify(&con->xendev);
if (buffer->max_capacity &&
buffer->size > buffer->max_capacity) {
/* Discard the middle of the data. */
size_t over = buffer->size - buffer->max_capacity;
uint8_t *maxpos = buffer->data + buffer->max_capacity;
memmove(maxpos - over, maxpos, over);
buffer->data = g_realloc(buffer->data, buffer->max_capacity);
buffer->size = buffer->capacity = buffer->max_capacity;
if (buffer->consumed > buffer->max_capacity - over)
buffer->consumed = buffer->max_capacity - over;
}
}
static void buffer_advance(struct buffer *buffer, size_t len)
{
buffer->consumed += len;
if (buffer->consumed == buffer->size) {
buffer->consumed = 0;
buffer->size = 0;
}
}
static int ring_free_bytes(struct XenConsole *con)
{
struct xencons_interface *intf = con->sring;
XENCONS_RING_IDX cons, prod, space;
cons = intf->in_cons;
prod = intf->in_prod;
xen_mb();
space = prod - cons;
if (space > sizeof(intf->in))
return 0; /* ring is screwed: ignore it */
return (sizeof(intf->in) - space);
}
static int xencons_can_receive(void *opaque)
{
struct XenConsole *con = opaque;
return ring_free_bytes(con);
}
static void xencons_receive(void *opaque, const uint8_t *buf, int len)
{
struct XenConsole *con = opaque;
struct xencons_interface *intf = con->sring;
XENCONS_RING_IDX prod;
int i, max;
max = ring_free_bytes(con);
/* The can_receive() func limits this, but check again anyway */
if (max < len)
len = max;
prod = intf->in_prod;
for (i = 0; i < len; i++) {
intf->in[MASK_XENCONS_IDX(prod++, intf->in)] =
buf[i];
}
xen_wmb();
intf->in_prod = prod;
xen_pv_send_notify(&con->xendev);
}
static void xencons_send(struct XenConsole *con)
{
ssize_t len, size;
size = con->buffer.size - con->buffer.consumed;
if (qemu_chr_fe_backend_connected(&con->chr)) {
len = qemu_chr_fe_write(&con->chr,
con->buffer.data + con->buffer.consumed,
size);
} else {
len = size;
}
if (len < 1) {
if (!con->backlog) {
con->backlog = 1;
xen_pv_printf(&con->xendev, 1,
"backlog piling up, nobody listening?\n");
}
} else {
buffer_advance(&con->buffer, len);
if (con->backlog && len == size) {
con->backlog = 0;
xen_pv_printf(&con->xendev, 1, "backlog is gone\n");
}
}
}
/* -------------------------------------------------------------------- */
static int con_init(struct XenDevice *xendev)
{
struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
char *type, *dom, label[32];
int ret = 0;
const char *output;
/* setup */
dom = xs_get_domain_path(xenstore, con->xendev.dom);
if (!xendev->dev) {
snprintf(con->console, sizeof(con->console), "%s/console", dom);
} else {
snprintf(con->console, sizeof(con->console), "%s/device/console/%d", dom, xendev->dev);
}
free(dom);
type = xenstore_read_str(con->console, "type");
if (!type || strcmp(type, "ioemu") != 0) {
xen_pv_printf(xendev, 1, "not for me (type=%s)\n", type);
ret = -1;
goto out;
}
output = xenstore_read_str(con->console, "output");
/* no Xen override, use qemu output device */
if (output == NULL) {
if (con->xendev.dev) {
qemu_chr_fe_init(&con->chr, serial_hds[con->xendev.dev],
&error_abort);
}
} else {
snprintf(label, sizeof(label), "xencons%d", con->xendev.dev);
qemu_chr_fe_init(&con->chr,
qemu_chr_new(label, output), &error_abort);
}
xenstore_store_pv_console_info(con->xendev.dev,
qemu_chr_fe_get_driver(&con->chr));
out:
g_free(type);
return ret;
}
static int con_initialise(struct XenDevice *xendev)
{
struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
int limit;
if (xenstore_read_int(con->console, "ring-ref", &con->ring_ref) == -1)
return -1;
if (xenstore_read_int(con->console, "port", &con->xendev.remote_port) == -1)
return -1;
if (xenstore_read_int(con->console, "limit", &limit) == 0)
con->buffer.max_capacity = limit;
if (!xendev->dev) {
xen: Switch uses of xc_map_foreign_range into xc_map_foreign_pages In Xen 4.7 we are refactoring parts libxenctrl into a number of separate libraries which will provide backward and forward API and ABI compatiblity. One such library will be libxenforeignmemory which provides access to privileged foreign mappings and which will provide an interface equivalent to xc_map_foreign_{pages,bulk}. In preparation for this switch all uses of xc_map_foreign_range to xc_map_foreign_pages. This is trivial because size was always XC_PAGE_SIZE so the necessary adjustments are trivial: * Pass &mfn (an array of length 1) instead of mfn. The function takes a pointer to const, so there is no possibily of mfn changing due to this change. * Pass nr_pages=1 instead of size=XC_PAGE_SIZE There is one wrinkle in xen_console.c:con_initialise() where con->ring_ref is an int but can in some code paths (when !xendev->dev) be treated as an mfn. I think this is an existing latent truncation hazard on platforms where xen_pfn_t is 64-bit and int is 32-bit (e.g. amd64, both arm* variants). I'm unsure under what circumstances xendev->dev can be NULL or if anything elsewhere ensures the value fits into an int. For now I just use a temporary xen_pfn_t to in effect upcast the pointer from int* to xen_pfn_t*. In xenfb.c:common_bind we now explicitly launder the mfn into a xen_pfn_t, so it has the correct type to be passed to xc_map_foreign_pages and doesn't provoke warnings on 32-bit x86. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2016-01-15 14:23:40 +01:00
xen_pfn_t mfn = con->ring_ref;
xen: Switch uses of xc_map_foreign_{pages,bulk} to use libxenforeignmemory API. In Xen 4.7 we are refactoring parts libxenctrl into a number of separate libraries which will provide backward and forward API and ABI compatiblity. One such library will be libxenforeignmemory which provides access to privileged foreign mappings and which will provide an interface equivalent to xc_map_foreign_{pages,bulk}. The new xenforeignmemory_map() function behaves like xc_map_foreign_pages() when the err argument is NULL and like xc_map_foreign_bulk() when err is non-NULL, which maps into the shim here onto checking err == NULL and calling the appropriate old function. Note that xenforeignmemory_map() takes the number of pages before the arrays themselves, in order to support potentially future use of variable-length-arrays in the prototype (in the future, when Xen's baseline toolchain requirements are new enough to ensure VLAs are supported). In preparation for adding support for libxenforeignmemory add support to the <=4.0 and <=4.6 compat code in xen_common.h to allow us to switch to using the new API. These shims will disappear for versions of Xen which include libxenforeignmemory. Since libxenforeignmemory will have its own handle type but for <= 4.6 the functionality is provided by using a libxenctrl handle we introduce a new global xen_fmem alongside the existing xen_xc. In fact we make xen_fmem a pointer to the existing xen_xc, which then works correctly with both <=4.0 (xc handle is an int) and <=4.6 (xc handle is a pointer). In the latter case xen_fmem is actually a double indirect pointer, but it all falls out in the wash. Unlike libxenctrl libxenforeignmemory has an explicit unmap function, rather than just specifying that munmap should be used, so the unmap paths are updated to use xenforeignmemory_unmap, which is a shim for munmap on these versions of xen. The mappings in xen-hvm.c do not appear to be unmapped (which makes sense for a qemu-dm process) In fb_disconnect this results in a change from simply mmap over the existing mapping (with an implicit munmap) to expliclty unmapping with xenforeignmemory_unmap and then mapping the required anonymous memory in the same hole. I don't think this is a problem since any other thread which was racily touching this region would already be running the risk of hitting the mapping halfway through the call. If this is thought to be a problem then we could consider adding an extra API to the libxenforeignmemory interface to replace a foreign mapping with anonymous shared memory, but I'd prefer not to. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2016-01-15 14:23:41 +01:00
con->sring = xenforeignmemory_map(xen_fmem, con->xendev.dom,
PROT_READ|PROT_WRITE,
1, &mfn, NULL);
} else {
con->sring = xengnttab_map_grant_ref(xendev->gnttabdev, con->xendev.dom,
con->ring_ref,
PROT_READ|PROT_WRITE);
}
if (!con->sring)
return -1;
xen_be_bind_evtchn(&con->xendev);
qemu_chr_fe_set_handlers(&con->chr, xencons_can_receive,
xencons_receive, NULL, NULL, con, NULL, true);
xen_pv_printf(xendev, 1,
"ring mfn %d, remote port %d, local port %d, limit %zd\n",
con->ring_ref,
con->xendev.remote_port,
con->xendev.local_port,
con->buffer.max_capacity);
return 0;
}
static void con_disconnect(struct XenDevice *xendev)
{
struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
qemu_chr_fe_deinit(&con->chr, false);
xen_pv_unbind_evtchn(&con->xendev);
if (con->sring) {
if (!xendev->dev) {
xen: Switch uses of xc_map_foreign_{pages,bulk} to use libxenforeignmemory API. In Xen 4.7 we are refactoring parts libxenctrl into a number of separate libraries which will provide backward and forward API and ABI compatiblity. One such library will be libxenforeignmemory which provides access to privileged foreign mappings and which will provide an interface equivalent to xc_map_foreign_{pages,bulk}. The new xenforeignmemory_map() function behaves like xc_map_foreign_pages() when the err argument is NULL and like xc_map_foreign_bulk() when err is non-NULL, which maps into the shim here onto checking err == NULL and calling the appropriate old function. Note that xenforeignmemory_map() takes the number of pages before the arrays themselves, in order to support potentially future use of variable-length-arrays in the prototype (in the future, when Xen's baseline toolchain requirements are new enough to ensure VLAs are supported). In preparation for adding support for libxenforeignmemory add support to the <=4.0 and <=4.6 compat code in xen_common.h to allow us to switch to using the new API. These shims will disappear for versions of Xen which include libxenforeignmemory. Since libxenforeignmemory will have its own handle type but for <= 4.6 the functionality is provided by using a libxenctrl handle we introduce a new global xen_fmem alongside the existing xen_xc. In fact we make xen_fmem a pointer to the existing xen_xc, which then works correctly with both <=4.0 (xc handle is an int) and <=4.6 (xc handle is a pointer). In the latter case xen_fmem is actually a double indirect pointer, but it all falls out in the wash. Unlike libxenctrl libxenforeignmemory has an explicit unmap function, rather than just specifying that munmap should be used, so the unmap paths are updated to use xenforeignmemory_unmap, which is a shim for munmap on these versions of xen. The mappings in xen-hvm.c do not appear to be unmapped (which makes sense for a qemu-dm process) In fb_disconnect this results in a change from simply mmap over the existing mapping (with an implicit munmap) to expliclty unmapping with xenforeignmemory_unmap and then mapping the required anonymous memory in the same hole. I don't think this is a problem since any other thread which was racily touching this region would already be running the risk of hitting the mapping halfway through the call. If this is thought to be a problem then we could consider adding an extra API to the libxenforeignmemory interface to replace a foreign mapping with anonymous shared memory, but I'd prefer not to. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2016-01-15 14:23:41 +01:00
xenforeignmemory_unmap(xen_fmem, con->sring, 1);
} else {
xengnttab_unmap(xendev->gnttabdev, con->sring, 1);
}
con->sring = NULL;
}
}
static void con_event(struct XenDevice *xendev)
{
struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
buffer_append(con);
if (con->buffer.size - con->buffer.consumed)
xencons_send(con);
}
/* -------------------------------------------------------------------- */
struct XenDevOps xen_console_ops = {
.size = sizeof(struct XenConsole),
.flags = DEVOPS_FLAG_IGNORE_STATE|DEVOPS_FLAG_NEED_GNTDEV,
.init = con_init,
.initialise = con_initialise,
.event = con_event,
.disconnect = con_disconnect,
};