1 files changed, 142 insertions, 0 deletions
diff --git a/xen/grant.c b/xen/grant.c
new file mode 100644
index 0000000..505d202
--- /dev/null
+++ b/xen/grant.c
@@ -0,0 +1,142 @@
+/*
+ *  Copyright (C) 2006 Samuel Thibault <samuel.thibault@ens-lyon.org>
+ *
+ * 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 ; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 the program ; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <sys/types.h>
+#include <mach/vm_param.h>
+#include <machine/spl.h>
+#include <vm/pmap.h>
+#include <vm/vm_map.h>
+#include <vm/vm_kern.h>
+#include "grant.h"
+
+#define NR_RESERVED_ENTRIES 8
+#define NR_GRANT_PAGES 4
+
+decl_simple_lock_data(static,lock);
+static struct grant_entry *grants;
+static vm_map_entry_t grants_map_entry;
+static int last_grant = NR_RESERVED_ENTRIES;
+
+static grant_ref_t free_grants = -1;
+
+static grant_ref_t grant_alloc(void) {
+	grant_ref_t grant;
+	if (free_grants != -1) {
+		grant = free_grants;
+		free_grants = grants[grant].frame;
+	} else {
+		grant = last_grant++;
+		if (grant == (NR_GRANT_PAGES * PAGE_SIZE)/sizeof(*grants))
+			panic("not enough grant entries, increase NR_GRANT_PAGES");
+	}
+	return grant;
+}
+
+static void grant_free(grant_ref_t grant) {
+	grants[grant].frame = free_grants;
+	free_grants = grant;
+}
+
+static grant_ref_t grant_set(domid_t domid, unsigned long mfn, uint16_t flags) {
+	spl_t spl = splhigh();
+	simple_lock(&lock);
+
+	grant_ref_t grant = grant_alloc();
+	grants[grant].domid = domid;
+	grants[grant].frame = mfn;
+	wmb();
+	grants[grant].flags = flags;
+
+	simple_unlock(&lock);
+	splx(spl);
+	return grant;
+}
+
+grant_ref_t hyp_grant_give(domid_t domid, unsigned long frame, int readonly) {
+	return grant_set(domid, pfn_to_mfn(frame),
+		GTF_permit_access | (readonly ? GTF_readonly : 0));
+}
+
+grant_ref_t hyp_grant_accept_transfer(domid_t domid, unsigned long frame) {
+	return grant_set(domid, frame, GTF_accept_transfer);
+}
+
+unsigned long hyp_grant_finish_transfer(grant_ref_t grant) {
+	unsigned long frame;
+	spl_t spl = splhigh();
+	simple_lock(&lock);
+
+	if (!(grants[grant].flags & GTF_transfer_committed))
+		panic("grant transfer %x not committed\n", grant);
+	while (!(grants[grant].flags & GTF_transfer_completed))
+		machine_relax();
+	rmb();
+	frame = grants[grant].frame;
+	grant_free(grant);
+
+	simple_unlock(&lock);
+	splx(spl);
+	return frame;
+}
+
+void hyp_grant_takeback(grant_ref_t grant) {
+	spl_t spl = splhigh();
+	simple_lock(&lock);
+
+	if (grants[grant].flags & (GTF_reading|GTF_writing))
+		panic("grant %d still in use (%lx)\n", grant, grants[grant].flags);
+
+	/* Note: this is not safe, a cmpxchg is needed, see grant_table.h */
+	grants[grant].flags = 0;
+	wmb();
+
+	grant_free(grant);
+
+	simple_unlock(&lock);
+	splx(spl);
+}
+
+void *hyp_grant_address(grant_ref_t grant) {
+	return &grants[grant];
+}
+
+void hyp_grant_init(void) {
+	struct gnttab_setup_table setup;
+	unsigned long frame[NR_GRANT_PAGES];
+	long ret;
+	int i;
+	vm_offset_t addr;
+
+	setup.dom = DOMID_SELF;
+	setup.nr_frames = NR_GRANT_PAGES;
+	setup.frame_list = (void*) kvtolin(frame);
+
+	ret = hyp_grant_table_op(GNTTABOP_setup_table, kvtolin(&setup), 1);
+	if (ret)
+		panic("setup grant table error %d", ret);
+	if (setup.status)
+		panic("setup grant table: %d\n", setup.status);
+	
+	simple_lock_init(&lock);
+	vm_map_find_entry(kernel_map, &addr, NR_GRANT_PAGES * PAGE_SIZE,
+			  (vm_offset_t) 0, kernel_object, &grants_map_entry);
+	grants = (void*) addr;
+
+	for (i = 0; i < NR_GRANT_PAGES; i++)
+		pmap_map_mfn((void *)grants + i * PAGE_SIZE, frame[i]);
+}