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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/2] xenstored: Use xenbus_backend device on Linux
On Thu, 2011-12-15 at 10:41 +0000, Bastian Blank wrote:
> xenstored: Use xenbus_backend device on Linux
>
> This patch is done on top of 4.1 for now. The kernel part is already
> merged.
It compiles and builds on unstable too. I didn't try it but since this
stuff rarely changes I don't see why it wouldn't work just as well there
too.
> diff -r 1c89f7d29fbb tools/xenstore/xenstored_linux.c
> --- a/tools/xenstore/xenstored_linux.c Thu Dec 08 16:50:28 2011 +0000
> +++ b/tools/xenstore/xenstored_linux.c Sat Dec 10 19:38:54 2011 +0100
We need to make a similar change to
tools/ocaml/xenstored/domains.ml:create0 which is tricky since you can't
make an ioctl call from pure ocaml so a C binding is needed.
However we already have a low-level library (libxenctrl) which abstracts
these sorts of low level differences across platforms and which has
existing language bindings so reimplementing this stuff multiple times
in multiple languages seems a bit sub-optimal when we could just write
it once and extend the language bindings to cover the new functionality.
The following doesn't implement non-Linux or the ocaml side yet but it
gives the gist of what I'm thinking.
Ian.
diff -r 0c92f4561443 tools/libxc/xc_linux_osdep.c
--- a/tools/libxc/xc_linux_osdep.c Thu Dec 15 10:41:58 2011 +0000
+++ b/tools/libxc/xc_linux_osdep.c Thu Dec 15 17:04:57 2011 +0000
@@ -35,6 +35,7 @@
#include <xen/sys/evtchn.h>
#include <xen/sys/gntdev.h>
#include <xen/sys/gntalloc.h>
+#include <xen/sys/xenbus_dev.h>
#include "xenctrl.h"
#include "xenctrlosdep.h"
@@ -43,6 +44,10 @@
#define PERROR(_m, _a...) xc_osdep_log(xch,XTL_ERROR,XC_INTERNAL_ERROR,_m \
" (%d = %s)", ## _a , errno, xc_strerror(xch, errno))
+#define XENSTORED_DEV "/dev/xen/xenbus_backend"
+#define XENSTORED_PROC_KVA "/proc/xen/xsd_kva"
+#define XENSTORED_PROC_PORT "/proc/xen/xsd_port"
+
static xc_osdep_handle linux_privcmd_open(xc_interface *xch)
{
int flags, saved_errno;
@@ -367,6 +372,77 @@ static void *linux_privcmd_map_foreign_r
return ret;
}
+static evtchn_port_t xenbus_proc_evtchn(void)
+{
+ int fd;
+ int rc;
+ evtchn_port_t port;
+ char str[20];
+
+ fd = open(XENSTORED_PROC_PORT, O_RDONLY);
+ if (fd == -1)
+ return -1;
+
+ rc = read(fd, str, sizeof(str));
+ if (rc == -1)
+ {
+ int err = errno;
+ close(fd);
+ errno = err;
+ return -1;
+ }
+
+ str[rc] = '\0';
+ port = strtoul(str, NULL, 0);
+
+ close(fd);
+ return port;
+}
+
+static int linux_xenbus_backend_interface(xc_interface *xch, xc_osdep_handle
h, void **map, evtchn_port_t *port)
+{
+ int ret, fd;
+ void *addr;
+
+ fd = open(XENSTORED_DEV, O_RDWR);
+ if (fd == -1)
+ {
+ if ( errno != ENOENT )
+ return -1;
+
+ /* Try /proc interface */
+ ret = xenbus_proc_evtchn();
+ if ( ret < 0 )
+ return -1;
+
+ *port = ret;
+
+ fd = open(XENSTORED_PROC_KVA, O_RDWR);
+ if ( fd == -1 )
+ return -1;
+ } else {
+ ret = ioctl(fd, IOCTL_XENBUS_BACKEND_EVTCHN);
+ if ( ret < 0 )
+ {
+ close(fd);
+ return -1;
+ }
+ *port = ret;
+ }
+
+ addr = mmap(NULL, getpagesize(), PROT_READ|PROT_WRITE,
+ MAP_SHARED, fd, 0);
+ if ( addr == MAP_FAILED )
+ {
+ close(fd);
+ return -1;
+ }
+
+ *map = addr;
+ close(fd);
+ return 0;
+}
+
static struct xc_osdep_ops linux_privcmd_ops = {
.open = &linux_privcmd_open,
.close = &linux_privcmd_close,
@@ -381,6 +457,7 @@ static struct xc_osdep_ops linux_privcmd
.map_foreign_bulk = &linux_privcmd_map_foreign_bulk,
.map_foreign_range = &linux_privcmd_map_foreign_range,
.map_foreign_ranges = &linux_privcmd_map_foreign_ranges,
+ .xenbus_backend_interface = &linux_xenbus_backend_interface,
},
};
diff -r 0c92f4561443 tools/libxc/xc_misc.c
--- a/tools/libxc/xc_misc.c Thu Dec 15 10:41:58 2011 +0000
+++ b/tools/libxc/xc_misc.c Thu Dec 15 17:04:57 2011 +0000
@@ -633,6 +633,14 @@ int xc_hvm_inject_trap(
return rc;
}
+int xc_xenbus_backend_interface(xc_interface *xch, void **map, evtchn_port_t
*port)
+{
+ if ( xch->ops->u.privcmd.xenbus_backend_interface )
+ return xch->ops->u.privcmd.xenbus_backend_interface
+ (xch, xch->ops_handle, map, port);
+ return -ENOSYS;
+}
+
/*
* Local variables:
* mode: C
diff -r 0c92f4561443 tools/libxc/xenctrl.h
--- a/tools/libxc/xenctrl.h Thu Dec 15 10:41:58 2011 +0000
+++ b/tools/libxc/xenctrl.h Thu Dec 15 17:04:57 2011 +0000
@@ -324,6 +324,11 @@ int xc_get_cpumap_size(xc_interface *xch
xc_cpumap_t xc_cpumap_alloc(xc_interface *xch);
/*
+ * Xenbus backend
+ */
+int xc_xenbus_backend_interface(xc_interface *xch, void **map, evtchn_port_t
*port);
+
+/*
* DOMAIN DEBUGGING FUNCTIONS
*/
diff -r 0c92f4561443 tools/libxc/xenctrlosdep.h
--- a/tools/libxc/xenctrlosdep.h Thu Dec 15 10:41:58 2011 +0000
+++ b/tools/libxc/xenctrlosdep.h Thu Dec 15 17:04:57 2011 +0000
@@ -89,6 +89,7 @@ struct xc_osdep_ops
void *(*map_foreign_ranges)(xc_interface *xch, xc_osdep_handle h,
uint32_t dom, size_t size, int prot,
size_t chunksize, privcmd_mmap_entry_t
entries[],
int nentries);
+ int (*xenbus_backend_interface)(xc_interface *xch, xc_osdep_handle
h, void **map, evtchn_port_t *port);
} privcmd;
struct {
int (*fd)(xc_evtchn *xce, xc_osdep_handle h);
diff -r 0c92f4561443 tools/xenstore/xenstored_domain.c
--- a/tools/xenstore/xenstored_domain.c Thu Dec 15 10:41:58 2011 +0000
+++ b/tools/xenstore/xenstored_domain.c Thu Dec 15 17:04:57 2011 +0000
@@ -565,23 +565,20 @@ void restore_existing_connections(void)
{
}
-static int dom0_init(void)
+static int dom0_init(xc_interface *xch)
{
evtchn_port_t port;
+ void *intf;
struct domain *dom0;
- port = xenbus_evtchn();
- if (port == -1)
+ if (xc_xenbus_backend_interface(xch, &intf, &port) < 0)
return -1;
dom0 = new_domain(NULL, 0, port);
if (dom0 == NULL)
return -1;
- dom0->interface = xenbus_map();
- if (dom0->interface == NULL)
- return -1;
-
+ dom0->interface = intf;
talloc_steal(dom0->conn, dom0);
xc_evtchn_notify(xce_handle, dom0->port);
@@ -608,7 +605,7 @@ void domain_init(void)
if (xce_handle == NULL)
barf_perror("Failed to open evtchn device");
- if (dom0_init() != 0)
+ if (dom0_init(*xc_handle) != 0)
barf_perror("Failed to initialize dom0 state");
if ((rc = xc_evtchn_bind_virq(xce_handle, VIRQ_DOM_EXC)) == -1)
diff -r 0c92f4561443 tools/xenstore/xenstored_linux.c
--- a/tools/xenstore/xenstored_linux.c Thu Dec 15 10:41:58 2011 +0000
+++ b/tools/xenstore/xenstored_linux.c Thu Dec 15 17:04:57 2011 +0000
@@ -18,84 +18,8 @@
#include <sys/ioctl.h>
#include <sys/mman.h>
-#include <xen/sys/xenbus_dev.h>
-
#include "xenstored_core.h"
-#define XENSTORED_DEV "/dev/xen/xenbus_backend"
-#define XENSTORED_PROC_KVA "/proc/xen/xsd_kva"
-#define XENSTORED_PROC_PORT "/proc/xen/xsd_port"
-
-static evtchn_port_t xenbus_proc_evtchn(void)
-{
- int fd;
- int rc;
- evtchn_port_t port;
- char str[20];
-
- fd = open(XENSTORED_PROC_PORT, O_RDONLY);
- if (fd == -1)
- return -1;
-
- rc = read(fd, str, sizeof(str));
- if (rc == -1)
- {
- int err = errno;
- close(fd);
- errno = err;
- return -1;
- }
-
- str[rc] = '\0';
- port = strtoul(str, NULL, 0);
-
- close(fd);
- return port;
-}
-
-evtchn_port_t xenbus_evtchn(void)
-{
- int fd;
- long ret;
-
- fd = open(XENSTORED_DEV, O_RDONLY);
- if (fd == -1)
- {
- if (errno == ENOENT)
- return xenbus_proc_evtchn();
- return -1;
- }
-
- ret = ioctl(fd, IOCTL_XENBUS_BACKEND_EVTCHN);
- if (ret == -1)
- return -1;
-
- close(fd);
- return ret;
-}
-
-void *xenbus_map(void)
-{
- int fd;
- void *addr;
-
- fd = open(XENSTORED_DEV, O_RDWR);
- if (fd == -1 && errno == ENOENT)
- fd = open(XENSTORED_PROC_KVA, O_RDWR);
- if (fd == -1)
- return NULL;
-
- addr = mmap(NULL, getpagesize(), PROT_READ|PROT_WRITE,
- MAP_SHARED, fd, 0);
-
- if (addr == MAP_FAILED)
- addr = NULL;
-
- close(fd);
-
- return addr;
-}
-
void xenbus_notify_running(void)
{
}
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