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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH DNA 5/6] tools/xenstored: restore support for mapping ring as foreign memory
Restore the previous way of mapping the xenstore ring using foreign
memory. Use xenforeignmemory instead of libxc in order to avoid adding
another dependency on a unstable interface.
This in turn requires storing the gfn into xs_state_connection for
resume purposes, which breaks the current format.
Note this is a preparatory patch in order to support the usage of
xenstore on domains without grant table. This not only allows xenstore
usage, but also makes things like "@introduceDomain" events work when
using such guests, otherwise the mapping done in introduce_domain
fails and the "@introduceDomain" event won't be signaled.
Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
tools/xenstore/Makefile | 4 +-
tools/xenstore/include/xenstore_state.h | 1 +
tools/xenstore/xenstored_domain.c | 69 +++++++++++++++++++------
3 files changed, 56 insertions(+), 18 deletions(-)
diff --git a/tools/xenstore/Makefile b/tools/xenstore/Makefile
index 292b478fa1..9a9f7be5cb 100644
--- a/tools/xenstore/Makefile
+++ b/tools/xenstore/Makefile
@@ -67,10 +67,10 @@ $(XENSTORED_OBJS): CFLAGS += $(SYSTEMD_CFLAGS)
xenstored: LDFLAGS += $(SYSTEMD_LIBS)
endif
-$(XENSTORED_OBJS): CFLAGS += $(CFLAGS_libxengnttab)
+$(XENSTORED_OBJS): CFLAGS += $(CFLAGS_libxengnttab)
$(CFLAGS_libxenforeignmemory)
xenstored: $(XENSTORED_OBJS)
- $(CC) $^ $(LDFLAGS) $(LDLIBS_libxenevtchn) $(LDLIBS_libxengnttab)
$(LDLIBS_libxenctrl) $(LDLIBS_xenstored) $(SOCKET_LIBS) -o $@ $(APPEND_LDFLAGS)
+ $(CC) $^ $(LDFLAGS) $(LDLIBS_libxenevtchn) $(LDLIBS_libxengnttab)
$(LDLIBS_libxenforeignmemory) $(LDLIBS_libxenctrl) $(LDLIBS_xenstored)
$(SOCKET_LIBS) -o $@ $(APPEND_LDFLAGS)
xenstored.a: $(XENSTORED_OBJS)
$(AR) cr $@ $^
diff --git a/tools/xenstore/include/xenstore_state.h
b/tools/xenstore/include/xenstore_state.h
index ae0d053c8f..8dcc8d9d8b 100644
--- a/tools/xenstore/include/xenstore_state.h
+++ b/tools/xenstore/include/xenstore_state.h
@@ -80,6 +80,7 @@ struct xs_state_connection {
uint16_t domid; /* Domain-Id. */
uint16_t tdomid; /* Id of target domain or DOMID_INVALID. */
uint32_t evtchn; /* Event channel port. */
+ uint64_t gfn; /* Store GFN. */
} ring;
int32_t socket_fd; /* File descriptor for socket connections. */
} spec;
diff --git a/tools/xenstore/xenstored_domain.c
b/tools/xenstore/xenstored_domain.c
index 8930303773..f3563e47aa 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -33,10 +33,12 @@
#include <xenevtchn.h>
#include <xenctrl.h>
+#include <xenforeignmemory.h>
#include <xen/grant_table.h>
static xc_interface *xc_handle;
xengnttab_handle *xgt_handle;
+static xenforeignmemory_handle *xfm_handle;
static evtchn_port_t virq_port;
xenevtchn_handle *xce_handle = NULL;
@@ -66,12 +68,18 @@ struct domain
/* Generation count at domain introduction time. */
uint64_t generation;
+ /* Store GFN (if using a ring connection). */
+ xen_pfn_t gfn;
+
/* Have we noticed that this domain is shutdown? */
bool shutdown;
/* Has domain been officially introduced? */
bool introduced;
+ /* Is the ring memory foreign mapped? */
+ bool foreign_mapped;
+
/* number of entry from this domain in the store */
int nbentry;
@@ -196,16 +204,29 @@ static const struct interface_funcs domain_funcs = {
.can_read = domain_can_read,
};
-static void *map_interface(domid_t domid)
+static void *map_interface(domid_t domid, xen_pfn_t gfn, bool *foreign_mapped)
{
- return xengnttab_map_grant_ref(xgt_handle, domid,
- GNTTAB_RESERVED_XENSTORE,
- PROT_READ|PROT_WRITE);
+ void *map = xengnttab_map_grant_ref(xgt_handle, domid,
+ GNTTAB_RESERVED_XENSTORE,
+ PROT_READ|PROT_WRITE);
+
+ if (!map)
+ {
+ map = xenforeignmemory_map(xfm_handle, domid,
+ PROT_READ|PROT_WRITE, 1,
+ &gfn, NULL);
+ *foreign_mapped = !!map;
+ }
+
+ return map;
}
-static void unmap_interface(void *interface)
+static void unmap_interface(void *interface, bool foreign_mapped)
{
- xengnttab_unmap(xgt_handle, interface, 1);
+ if (foreign_mapped)
+ xenforeignmemory_unmap(xfm_handle, interface, 1);
+ else
+ xengnttab_unmap(xgt_handle, interface, 1);
}
static int destroy_domain(void *_domain)
@@ -228,7 +249,8 @@ static int destroy_domain(void *_domain)
if (domain->domid == 0)
unmap_xenbus(domain->interface);
else
- unmap_interface(domain->interface);
+ unmap_interface(domain->interface,
+ domain->foreign_mapped);
}
fire_watches(NULL, domain, "@releaseDomain", NULL, false, NULL);
@@ -363,12 +385,15 @@ static struct domain *find_or_alloc_domain(const void
*ctx, unsigned int domid)
return domain ? : alloc_domain(ctx, domid);
}
-static int new_domain(struct domain *domain, int port, bool restore)
+static int new_domain(struct domain *domain, int port, xen_pfn_t gfn,
+ bool foreign_mapped, bool restore)
{
int rc;
domain->port = 0;
domain->shutdown = false;
+ domain->gfn = gfn;
+ domain->foreign_mapped = foreign_mapped;
domain->path = talloc_domain_path(domain, domain->domid);
if (!domain->path) {
errno = ENOMEM;
@@ -436,7 +461,8 @@ static void domain_conn_reset(struct domain *domain)
static struct domain *introduce_domain(const void *ctx,
unsigned int domid,
- evtchn_port_t port, bool restore)
+ evtchn_port_t port, xen_pfn_t gfn,
+ bool restore)
{
struct domain *domain;
int rc;
@@ -448,17 +474,21 @@ static struct domain *introduce_domain(const void *ctx,
return NULL;
if (!domain->introduced) {
+ bool foreign_mapped = false;
+
interface = is_master_domain ? xenbus_map()
- : map_interface(domid);
+ : map_interface(domid, gfn,
+ &foreign_mapped);
if (!interface && !restore)
return NULL;
- if (new_domain(domain, port, restore)) {
+ if (new_domain(domain, port, gfn, foreign_mapped, restore)) {
rc = errno;
if (interface) {
if (is_master_domain)
unmap_xenbus(interface);
else
- unmap_interface(interface);
+ unmap_interface(interface,
+ foreign_mapped);
}
errno = rc;
return NULL;
@@ -489,19 +519,20 @@ int do_introduce(struct connection *conn, struct
buffered_data *in)
char *vec[3];
unsigned int domid;
evtchn_port_t port;
+ xen_pfn_t gfn;
if (get_strings(in, vec, ARRAY_SIZE(vec)) < ARRAY_SIZE(vec))
return EINVAL;
domid = atoi(vec[0]);
- /* Ignore the gfn, we don't need it. */
+ gfn = atol(vec[1]);
port = atoi(vec[2]);
/* Sanity check args. */
if (port <= 0)
return EINVAL;
- domain = introduce_domain(in, domid, port, false);
+ domain = introduce_domain(in, domid, port, gfn, false);
if (!domain)
return errno;
@@ -718,7 +749,7 @@ void dom0_init(void)
if (port == -1)
barf_perror("Failed to initialize dom0 port");
- dom0 = introduce_domain(NULL, xenbus_master_domid(), port, false);
+ dom0 = introduce_domain(NULL, xenbus_master_domid(), port, 0, false);
if (!dom0)
barf_perror("Failed to initialize dom0");
@@ -758,6 +789,10 @@ void domain_init(int evtfd)
*/
xengnttab_set_max_grants(xgt_handle, DOMID_FIRST_RESERVED);
+ xfm_handle = xenforeignmemory_open(NULL, 0);
+ if (!xfm_handle)
+ barf_perror("Failed to create handle for foreign memory");
+
if (evtfd < 0)
xce_handle = xenevtchn_open(NULL, XENEVTCHN_NO_CLOEXEC);
else
@@ -1189,6 +1224,7 @@ const char *dump_state_connections(FILE *fp)
sc.spec.ring.tdomid = c->target ? c->target->id
: DOMID_INVALID;
sc.spec.ring.evtchn = c->domain->port;
+ sc.spec.ring.gfn = c->domain->gfn;
} else {
sc.conn_type = XS_STATE_CONN_TYPE_SOCKET;
sc.spec.socket_fd = c->fd;
@@ -1290,7 +1326,8 @@ void read_state_connection(const void *ctx, const void
*state)
#endif
} else {
domain = introduce_domain(ctx, sc->spec.ring.domid,
- sc->spec.ring.evtchn, true);
+ sc->spec.ring.evtchn,
+ sc->spec.ring.gfn, true);
if (!domain)
barf("domain allocation error");
--
2.33.0
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