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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [v3 2/5] Qemu-Xen-vTPM: Xen frontend driver infrastructure
On Tue, 30 Dec 2014, Quan Xu wrote:
> This patch adds infrastructure for xen front drivers living in qemu,
> so drivers don't need to implement common stuff on their own. It's
> mostly xenbus management stuff: some functions to access XenStore,
> setting up XenStore watches, callbacks on device discovery and state
> changes, and handle event channel between the virtual machines.
>
> Call xen_fe_register() function to register XenDevOps, and make sure,
> XenDevOps's flags is DEVOPS_FLAG_FE, which is flag bit to point out
> the XenDevOps is Xen frontend.
>
> --Changes in v3:
> -New xen_frontend.c file
> -Move xenbus_switch_state() to xen_frontend.c
> -Move xen_stubdom_be() to xenstore_fe_read_be_str()
> -Move *_stubdom_*() to *_fe_*()
>
> Signed-off-by: Quan Xu <quan.xu@xxxxxxxxx>
> ---
> hw/xen/Makefile.objs | 2 +-
> hw/xen/xen_backend.c | 11 +-
> hw/xen/xen_frontend.c | 323
> +++++++++++++++++++++++++++++++++++++++++++
> include/hw/xen/xen_backend.h | 14 ++
> 4 files changed, 348 insertions(+), 2 deletions(-)
> create mode 100644 hw/xen/xen_frontend.c
>
> diff --git a/hw/xen/Makefile.objs b/hw/xen/Makefile.objs
> index a0ca0aa..b0bb065 100644
> --- a/hw/xen/Makefile.objs
> +++ b/hw/xen/Makefile.objs
> @@ -1,5 +1,5 @@
> # xen backend driver support
> -common-obj-$(CONFIG_XEN_BACKEND) += xen_backend.o xen_devconfig.o
> +common-obj-$(CONFIG_XEN_BACKEND) += xen_backend.o xen_devconfig.o
> xen_frontend.o
>
> obj-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen-host-pci-device.o
> obj-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen_pt.o xen_pt_config_init.o
> xen_pt_msi.o
> diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c
> index b2cb22b..ad6e324 100644
> --- a/hw/xen/xen_backend.c
> +++ b/hw/xen/xen_backend.c
> @@ -275,7 +275,7 @@ static struct XenDevice *xen_be_get_xendev(const char
> *type, int dom, int dev,
> /*
> * release xen backend device.
> */
> -static struct XenDevice *xen_be_del_xendev(int dom, int dev)
> +struct XenDevice *xen_be_del_xendev(int dom, int dev)
> {
> struct XenDevice *xendev, *xnext;
>
> @@ -681,6 +681,10 @@ static void xenstore_update(void *unused)
> if (sscanf(vec[XS_WATCH_TOKEN], "fe:%" PRIxPTR, &ptr) == 1) {
> xenstore_update_fe(vec[XS_WATCH_PATH], (void*)ptr);
> }
> + if (sscanf(vec[XS_WATCH_TOKEN], "stub:%" PRIxPTR ":%d:%" PRIxPTR,
> + &type, &dom, &ops) == 3) {
> + xenstore_fe_update(vec[XS_WATCH_PATH], (void *)type, dom, (void
> *)ops);
> + }
Why "stub:"? Where is it coming from?
I think that the xenstore_update function should be moved to a new file:
we don't want xen_backend.c to be handling any frontend updates.
Maybe you could create a new file, hw/xen/xen_pvdev.c?
> cleanup:
> free(vec);
> @@ -808,3 +812,8 @@ void xen_be_printf(struct XenDevice *xendev, int
> msg_level, const char *fmt, ...
> }
> qemu_log_flush();
> }
> +
> +void xen_qtail_insert_xendev(struct XenDevice *xendev)
> +{
> + QTAILQ_INSERT_TAIL(&xendevs, xendev, next);
> +}
You should either move the xendevs queue to the new file xen_pvdev.c or
you should introduce a separate xendevs queue for frontends in
xen_frontend.c.
> diff --git a/hw/xen/xen_frontend.c b/hw/xen/xen_frontend.c
> new file mode 100644
> index 0000000..07ffc5c
> --- /dev/null
> +++ b/hw/xen/xen_frontend.c
> @@ -0,0 +1,323 @@
> +/*
> + * Xen frontend driver infrastructure
> + *
> + * Copyright (c) 2014 Intel Corporation
> + * Authors:
> + * Quan Xu <quan.xu@xxxxxxxxx>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2 of the License, or (at your option) any later version.
> + *
> + * This library 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
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see
> <http://www.gnu.org/licenses/>
> + */
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <stdarg.h>
> +#include <string.h>
> +#include <unistd.h>
> +#include <fcntl.h>
> +#include <inttypes.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <sys/mman.h>
> +#include <sys/signal.h>
> +
> +#include "hw/hw.h"
> +#include "sysemu/char.h"
> +#include "qemu/log.h"
> +#include "hw/xen/xen_backend.h"
> +#include <xen/grant_table.h>
> +
> +/* private */
> +static int debug;
> +
> +/* ------------------------------------------------------------- */
> +/*Get backend with fe type|domid, try to write the backend-id when
> + *create virtual machine.
> + *
> + *[XenStore]
> + *
> + *Dom.ID = ""
> + * device
> + * vtpm = ""
> + * 0 = ""
> + * backend-id = "ID"
> + *[..]
> + */
> +
> +char *xenstore_fe_read_be_str(const char *type, int dom, int dev)
> +{
> + char *val, *domu;
> + char path[XEN_BUFSIZE];
> + unsigned int len, ival;
> +
> + /*fe path*/
> + domu = xs_get_domain_path(xenstore, dom);
> + snprintf(path, sizeof(path), "%s/device/%s/%d/backend-id",
> + domu, type, dev);
> + g_free(domu);
> +
> + val = xs_read(xenstore, 0, path, &len);
> + if (!val || 1 != sscanf(val, "%d", &ival)) {
> + g_free(val);
> + return NULL;
> + }
> + g_free(val);
> +
> + /*be path*/
> + domu = xs_get_domain_path(xenstore, ival);
> +
> + return domu;
> +}
> +
> +/*make sure, initialize the 'xendev->fe' in xendev->ops->init() or
> + * xendev->ops->initialize()
> + */
> +int xenbus_switch_state(struct XenDevice *xendev, enum xenbus_state xbus)
> +{
> + xs_transaction_t xbt = XBT_NULL;
> +
> + if (xendev->fe_state == xbus) {
> + return 0;
> + }
> +
> + xendev->fe_state = xbus;
> + if (xendev->fe == NULL) {
> + xen_be_printf(NULL, 0, "xendev->fe is NULL\n");
> + return -1;
> + }
> +
> +retry_transaction:
> + xbt = xs_transaction_start(xenstore);
> + if (xbt == XBT_NULL) {
> + goto abort_transaction;
> + }
> +
> + if (xenstore_write_int(xendev->fe, "state", xbus)) {
> + goto abort_transaction;
> + }
> +
> + if (!xs_transaction_end(xenstore, xbt, 0)) {
> + if (errno == EAGAIN) {
> + goto retry_transaction;
> + }
> + }
> +
> + return 0;
> +
> +abort_transaction:
> + xs_transaction_end(xenstore, xbt, 1);
> + return -1;
> +}
> +
> +void xenstore_fe_update(char *watch, char *type, int dom, struct XenDevOps
> *ops)
> +{
> + struct XenDevice *xendev;
> + char path[XEN_BUFSIZE];
> + char *ptr, *bepath;
> + unsigned int len, dev;
> +
> + if (!(ops->flags & DEVOPS_FLAG_FE)) {
> + return;
> + }
> +
> + len = snprintf(path, sizeof(path), "backend/%s/%d", type, dom);
> + ptr = strstr(watch, path);
> + if (ptr == NULL) {
> + return;
> + }
> +
> + if (sscanf(ptr+len, "/%u/%255s", &dev, path) != 2) {
> + strcpy(path, "");
> + if (sscanf(ptr+len, "/%u", &dev) != 1) {
> + dev = -1;
> + }
> + }
> +
> + if (dev == -1) {
> + return;
> + }
> +
> + xendev = xen_fe_get_xendev(type, dom, dev, ops);
> + if (xendev != NULL) {
> + bepath = xs_read(xenstore, 0, xendev->be, &len);
> + /*bepath is NULL, indicates that the backend is not running,
> + *delete it.
> + */
> + if (bepath == NULL) {
> + xen_be_del_xendev(dom, dev);
> + } else {
> + free(bepath);
> + if (xendev->ops->backend_changed) {
> + xendev->ops->backend_changed(xendev, path);
> + }
> + }
> + }
> +}
> +
> +/*
> + * get xen fe device, allocate a new one if it doesn't exist.
> + */
> +struct XenDevice *xen_fe_get_xendev(const char *type, int dom, int dev,
> + struct XenDevOps *ops)
> +{
> + struct XenDevice *xendev;
> + char *stub;
> +
> + xendev = xen_be_find_xendev(type, dom, dev);
> + if (xendev) {
> + return xendev;
> + }
> +
> + /* init new xendev */
> + xendev = g_malloc0(ops->size);
> + xendev->type = type;
> + xendev->dom = dom;
> + xendev->dev = dev;
> + xendev->ops = ops;
> +
> + /*return if the ops->flags is not DEVOPS_FLAG_FE*/
> + if (!(ops->flags & DEVOPS_FLAG_FE)) {
> + return NULL;
> + }
> +
> + stub = xenstore_fe_read_be_str(xendev->type, xendev->dom, xendev->dev);
> + snprintf(xendev->be, sizeof(xendev->be), "%s/backend/%s/%d/%d",
> + stub, xendev->type, xendev->dom, xendev->dev);
> + g_free(stub);
> + snprintf(xendev->name, sizeof(xendev->name), "%s-%d",
> + xendev->type, xendev->dev);
> +
> + xendev->debug = debug;
> + xendev->local_port = -1;
> +
> + xendev->evtchndev = xen_xc_evtchn_open(NULL, 0);
> + if (xendev->evtchndev == XC_HANDLER_INITIAL_VALUE) {
> + xen_be_printf(NULL, 0, "can't open evtchn device\n");
> + g_free(xendev);
> + return NULL;
> + }
> + fcntl(xc_evtchn_fd(xendev->evtchndev), F_SETFD, FD_CLOEXEC);
> +
> + if (ops->flags & DEVOPS_FLAG_NEED_GNTDEV) {
> + xendev->gnttabdev = xen_xc_gnttab_open(NULL, 0);
> + if (xendev->gnttabdev == XC_HANDLER_INITIAL_VALUE) {
> + xen_be_printf(NULL, 0, "can't open gnttab device\n");
> + xc_evtchn_close(xendev->evtchndev);
> + g_free(xendev);
> + return NULL;
> + }
> + } else {
> + xendev->gnttabdev = XC_HANDLER_INITIAL_VALUE;
> + }
> +
> + xen_qtail_insert_xendev(xendev);
> +
> + if (xendev->ops->alloc) {
> + xendev->ops->alloc(xendev);
> + }
> +
> + return xendev;
> +}
> +
> +/* simplify QEMU side, a thread is running in Xen backend, which will
> + * connect frontend when the frontend is initialised. Call these initialised
> + * functions.
> + */
> +
> +static int xen_fe_check(struct XenDevice *xendev, uint32_t domid,
> + int handle)
> +{
> + int rc = 0;
> +
> + if (xendev->ops->init) {
> + rc = xendev->ops->init(xendev);
> + }
> +
> + if (rc != 0) {
> + xen_be_printf(xendev, 0, "xendev %s init error\n",
> + xendev->name);
> + goto err;
> + }
> +
> + if (xendev->ops->initialise) {
> + rc = xendev->ops->initialise(xendev);
> + }
> +
> + if (rc != 0) {
> + xen_be_printf(xendev, 0, "xendev %s initialise error\n",
> + xendev->name);
> + goto err;
> + }
Shouldn't you be checking the backend status before setting the frontend
to connected? Something like xen_be_try_connected?
> + if (xendev->ops->connected) {
> + xendev->ops->connected(xendev);
> + }
> +
> + return rc;
> +
> +err:
> + xen_be_del_xendev(domid, handle);
> + return -1;
> +}
> +
> +static int xenstore_fe_scan(const char *type, uint32_t domid,
> + struct XenDevOps *ops)
> +{
> + struct XenDevice *xendev;
> + char path[XEN_BUFSIZE], token[XEN_BUFSIZE];
> + char *domu;
> + unsigned int cdev, j;
> + char **dev = NULL;
> +
> + /*Xen frontend : /local/domain/ID */
> + domu = xs_get_domain_path(xenstore, domid);
> + snprintf(path, sizeof(path), "%s/device/%s",
> + domu, type);
> + free(domu);
> + dev = xs_directory(xenstore, 0, path, &cdev);
> + if (dev == NULL) {
> + return 0;
> + }
> +
> + for (j = 0; j < cdev; j++) {
> + xendev = xen_fe_get_xendev(type, domid, atoi(dev[j]), ops);
> + if (xendev == NULL) {
> + xen_be_printf(xendev, 0, "xendev is NULL.\n");
> + continue;
> + }
> +
> + /* simplify QEMU side, a thread is running in Xen backend, which will
> + * connect frontend when the frontend is initialised.
> + */
> + if (xen_fe_check(xendev, domid, atoi(dev[j])) < 0) {
> + xen_be_printf(xendev, 0, "xendev fe_check error.\n");
> + continue;
> + }
> +
> + /*setup watch*/
> + snprintf(token, sizeof(token), "stub:%p:%d:%p",
> + type, domid, xendev->ops);
> + if (!xs_watch(xenstore, xendev->be, token)) {
> + xen_be_printf(xendev, 0, "xs_watch failed.\n");
> + continue;
> + }
> + }
> +
> + free(dev);
> + return 0;
> +}
> +
> +int xen_fe_register(const char *type, struct XenDevOps *ops)
> +{
> + return xenstore_fe_scan(type, xen_domid, ops);
> +}
> diff --git a/include/hw/xen/xen_backend.h b/include/hw/xen/xen_backend.h
> index 3b4125e..06e202f 100644
> --- a/include/hw/xen/xen_backend.h
> +++ b/include/hw/xen/xen_backend.h
> @@ -15,6 +15,8 @@ struct XenDevice;
> #define DEVOPS_FLAG_NEED_GNTDEV 1
> /* don't expect frontend doing correct state transitions (aka console quirk)
> */
> #define DEVOPS_FLAG_IGNORE_STATE 2
> +/*dev is frontend device*/
> +#define DEVOPS_FLAG_FE 4
>
> struct XenDevOps {
> size_t size;
> @@ -80,6 +82,8 @@ int xenstore_read_fe_uint64(struct XenDevice *xendev, const
> char *node, uint64_t
> const char *xenbus_strstate(enum xenbus_state state);
> struct XenDevice *xen_be_find_xendev(const char *type, int dom, int dev);
> void xen_be_check_state(struct XenDevice *xendev);
> +struct XenDevice *xen_be_del_xendev(int dom, int dev);
> +void xen_qtail_insert_xendev(struct XenDevice *xendev);
>
> /* xen backend driver bits */
> int xen_be_init(void);
> @@ -91,6 +95,16 @@ int xen_be_send_notify(struct XenDevice *xendev);
> void xen_be_printf(struct XenDevice *xendev, int msg_level, const char *fmt,
> ...)
> GCC_FMT_ATTR(3, 4);
>
> +/*Xen frontend driver*/
> +int xen_fe_register(const char *type, struct XenDevOps *ops);
> +int xen_be_alloc_unbound(struct XenDevice *xendev, int dom, int remote_dom);
> +char *xenstore_fe_read_be_str(const char *type, int dom, int dev);
> +int xenbus_switch_state(struct XenDevice *xendev, enum xenbus_state xbus);
> +struct XenDevice *xen_fe_get_xendev(const char *type, int dom, int dev,
> + struct XenDevOps *ops);
> +void xenstore_fe_update(char *watch, char *type, int dom,
> + struct XenDevOps *ops);
> +
> /* actual backend drivers */
> extern struct XenDevOps xen_console_ops; /* xen_console.c */
> extern struct XenDevOps xen_kbdmouse_ops; /* xen_framebuffer.c */
> --
> 1.8.3.2
>
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