--- /dev/null
+#include "libxl_osdeps.h"
+#include "libxl_internal.h"
+#include "libxl_arch.h"
+
+#define SSHM_PATH(id) GCSPRINTF("/libxl/static_shm/%s", id)
+
+#define SSHM_ERROR(domid, sshmid, f, ...) \
+ LOGD(ERROR, domid, "static_shm id = %s: " f, sshmid, ##__VA_ARGS__)
+
+
+/* Set default values for libxl_static_shm */
+int libxl__sshm_setdefault(libxl__gc *gc, uint32_t domid,
+ libxl_static_shm *sshm)
+{
+ int rc;
+
+ if (sshm->role != LIBXL_SSHM_ROLE_BORROWER &&
+ sshm->role != LIBXL_SSHM_ROLE_OWNER)
+ return ERROR_INVAL;
+ if (sshm->begin & ~XC_PAGE_MASK ||
+ sshm->size & ~XC_PAGE_MASK ||
+ (sshm->offset != LIBXL_SSHM_RANGE_UNKNOWN &&
+ sshm->offset & ~XC_PAGE_MASK)) {
+ SSHM_ERROR(domid, sshm->id,
+ "begin/size/offset is not a multiple of 4K");
+ return ERROR_INVAL;
+ }
+
+ /* role-specific checks */
+ if (sshm->role == LIBXL_SSHM_ROLE_BORROWER) {
+ if (sshm->offset == LIBXL_SSHM_RANGE_UNKNOWN)
+ sshm->offset = 0;
+ if (sshm->cache_policy != LIBXL_SSHM_CACHEPOLICY_UNKNOWN) {
+ SSHM_ERROR(domid, sshm->id,
+ "cache_policy is only applicable to owner domains");
+ rc = ERROR_INVAL;
+ goto out;
+ }
+ } else {
+ if (sshm->offset != LIBXL_SSHM_RANGE_UNKNOWN) {
+ SSHM_ERROR(domid, sshm->id,
+ "offset is only applicable to borrower domains");
+ rc = ERROR_INVAL;
+ goto out;
+ }
+
+ rc = libxl__arch_domain_sshm_cachepolicy_setdefault(sshm);
+ if (rc) {
+ SSHM_ERROR(domid, sshm->id,
+ "cache policy not supported on this platform");
+ goto out;
+ }
+ }
+
+ rc = 0;
+out:
+ return rc;
+}
+
+/* Comparator for sorting sshm ranges by sshm->begin */
+static int sshm_range_cmp(const void *a, const void *b)
+{
+ libxl_static_shm *const *sshma = a, *const *sshmb = b;
+ return (*sshma)->begin > (*sshmb)->begin ? 1 : -1;
+}
+
+/* Check if the sshm borrower configs in @sshm overlap */
+int libxl__sshm_check_overlap(libxl__gc *gc, uint32_t domid,
+ libxl_static_shm *sshms, int len)
+{
+
+ const libxl_static_shm **borrower_sshms = NULL;
+ int num_borrowers;
+ int i;
+
+ if (!len) return 0;
+
+ borrower_sshms = libxl__calloc(gc, len, sizeof(borrower_sshms[0]));
+ num_borrowers = 0;
+ for (i = 0; i < len; ++i) {
+ if (sshms[i].role == LIBXL_SSHM_ROLE_BORROWER)
+ borrower_sshms[num_borrowers++] = sshms + i;
+ }
+ qsort(borrower_sshms, num_borrowers, sizeof(borrower_sshms[0]), sshm_range_cmp);
+
+ for (i = 0; i < num_borrowers - 1; ++i) {
+ if (borrower_sshms[i+1]->begin <
+ borrower_sshms[i]->begin + borrower_sshms[i]->size) {
+ SSHM_ERROR(domid, borrower_sshms[i+1]->id, "borrower ranges overlap.");
+ return ERROR_INVAL;
+ }
+ }
+
+ return 0;
+}
+
+/* libxl__sshm_do_map -- map pages into borrower's physmap
+ *
+ * This functions maps
+ * owner gfn: [@msshm->begin + @sshm->offset,
+ * @msshm->begin + @msshm->size + @sshm->offset)
+ * into
+ * borrower gfn: [@sshm->begin, @sshm->begin + @sshm->size)
+ *
+ * The gfns of the pages that are successfully mapped will be stored
+ * in @mapped, and the number of the gfns will be stored in @nmapped.
+ *
+ * The caller has to guarantee that all the values are page-aligned.
+ */
+static int libxl__sshm_do_map(libxl__gc *gc, uint32_t mid, uint32_t sid,
+ libxl_static_shm *sshm, libxl_static_shm *msshm,
+ xen_pfn_t *mapped, unsigned int *nmapped)
+{
+ int rc;
+ int i;
+ xen_pfn_t num_mpages, num_spages, num_success, offset;
+ int *errs;
+ xen_ulong_t *idxs;
+ xen_pfn_t *gpfns;
+
+ num_mpages = (msshm->size) >> XC_PAGE_SHIFT;
+ num_spages = (sshm->size) >> XC_PAGE_SHIFT;
+ offset = sshm->offset >> XC_PAGE_SHIFT;
+
+ /* Check range. Test offset < mpages first to avoid overflow */
+ if ((offset >= num_mpages) || (num_mpages - offset < num_spages)) {
+ SSHM_ERROR(sid, sshm->id, "exceeds owner's address space.");
+ rc = ERROR_INVAL;
+ goto out;
+ }
+
+ /* fill out the gfn's and do the mapping */
+ errs = libxl__calloc(gc, num_spages, sizeof(int));
+ idxs = libxl__calloc(gc, num_spages, sizeof(xen_ulong_t));
+ gpfns = libxl__calloc(gc, num_spages, sizeof(xen_pfn_t));
+ for (i = 0; i < num_spages; i++) {
+ idxs[i] = (msshm->begin >> XC_PAGE_SHIFT) + offset + i;
+ gpfns[i]= (sshm->begin >> XC_PAGE_SHIFT) + i;
+ }
+ rc = xc_domain_add_to_physmap_batch(CTX->xch,
+ sid, mid,
+ XENMAPSPACE_gmfn_share,
+ num_spages,
+ idxs, gpfns, errs);
+
+ num_success = 0;
+ for (i = 0; i < num_spages; i++) {
+ if (errs[i]) {
+ SSHM_ERROR(sid, sshm->id,
+ "can't map at address 0x%"PRIx64".",
+ gpfns[i] << XC_PAGE_SHIFT);
+ rc = ERROR_FAIL;
+ } else {
+ mapped[num_success++] = gpfns[i];
+ }
+ }
+ *nmapped = num_success;
+ if (rc) goto out;
+
+ rc = 0;
+out:
+ return rc;
+}
+
+/* Xenstore ops are protected by a transaction */
+static int libxl__sshm_incref(libxl__gc *gc, xs_transaction_t xt,
+ const char *sshm_path)
+{
+ int rc, count;
+ const char *count_path, *count_string;
+
+ count_path = GCSPRINTF("%s/usercnt", sshm_path);
+ rc = libxl__xs_read_checked(gc, xt, count_path, &count_string);
+ if (rc || count_string == NULL) goto out;
+ count = atoi(count_string);
+
+ count_string = GCSPRINTF("%d", count+1);
+ rc = libxl__xs_write_checked(gc, xt, count_path, count_string);
+ if (rc) goto out;
+
+ rc = 0;
+out:
+ return rc;
+}
+
+static int libxl__sshm_add_borrower(libxl__gc *gc, uint32_t domid,
+ libxl_static_shm *sshm)
+{
+ int rc, i;
+ const char *sshm_path, *borrower_path;
+ const char *dom_path, *dom_sshm_path, *dom_role_path;
+ const char *xs_value;
+ char *ents[9];
+ libxl_static_shm owner_sshm;
+ uint32_t owner_domid;
+ xen_pfn_t *mapped;
+ unsigned int nmapped = 0;
+ xs_transaction_t xt = XBT_NULL;
+
+ sshm_path = SSHM_PATH(sshm->id);
+ borrower_path = GCSPRINTF("%s/borrowers/%"PRIu32, sshm_path, domid);
+ dom_path = libxl__xs_get_dompath(gc, domid);
+ /* the domain should be in xenstore by now */
+ assert(dom_path);
+ dom_sshm_path = GCSPRINTF("%s/static_shm/%s", dom_path, sshm->id);
+ dom_role_path = GCSPRINTF("%s/role", dom_sshm_path);
+
+ /* prepare the borrower xenstore entries */
+ ents[0] = "begin";
+ ents[1] = GCSPRINTF("0x%"PRIx64, sshm->begin);
+ ents[2] = "size";
+ ents[3] = GCSPRINTF("0x%"PRIx64, sshm->size);
+ ents[4] = "offset";
+ ents[5] = GCSPRINTF("0x%"PRIx64, sshm->offset);
+ ents[6] = "prot";
+ ents[7] = libxl__strdup(gc, libxl_sshm_prot_to_string(sshm->prot));
+ ents[8] = NULL;
+
+ mapped = libxl__calloc(gc, sshm->size >> XC_PAGE_SHIFT, sizeof(xen_pfn_t));
+
+ for (;;) {
+ rc = libxl__xs_transaction_start(gc, &xt);
+ if (rc) goto out;
+
+ if (libxl__xs_read_checked(gc, xt, sshm_path, &xs_value)) {
+ SSHM_ERROR(domid, sshm->id, "no owner found.");
+ rc = ERROR_FAIL;
+ goto out;
+ }
+
+ /* every ID can appear in each domain at most once */
+ if (libxl__xs_read_checked(gc, xt, dom_sshm_path, &xs_value)) {
+ SSHM_ERROR(domid, sshm->id,
+ "domain tried to map the same ID twice.");
+ rc = ERROR_FAIL;
+ goto out;
+ }
+
+ /* look at the owner info and see if we could do the mapping */
+ rc = libxl__xs_read_checked(gc, xt,
+ GCSPRINTF("%s/prot", sshm_path),
+ &xs_value);
+ if (rc) goto out;
+ libxl_sshm_prot_from_string(xs_value, &owner_sshm.prot);
+
+ rc = libxl__xs_read_checked(gc, xt,
+ GCSPRINTF("%s/begin", sshm_path),
+ &xs_value);
+ if (rc) goto out;
+ owner_sshm.begin = strtoull(xs_value, NULL, 16);
+
+ rc = libxl__xs_read_checked(gc, xt,
+ GCSPRINTF("%s/size", sshm_path),
+ &xs_value);
+ if (rc) goto out;
+ owner_sshm.size = strtoull(xs_value, NULL, 16);
+
+ rc = libxl__xs_read_checked(gc, xt,
+ GCSPRINTF("%s/owner", sshm_path),
+ &xs_value);
+ if (rc) goto out;
+ owner_domid = strtoull(xs_value, NULL, 16);
+
+ if (sshm->prot == LIBXL_SSHM_PROT_UNKNOWN)
+ sshm->prot = owner_sshm.prot;
+
+ /* check if the borrower is asking too much permission */
+ if (owner_sshm.prot < sshm->prot) {
+ SSHM_ERROR(domid, sshm->id, "borrower is asking too much permission.");
+ rc = ERROR_INVAL;
+ goto out;
+ }
+
+ /* write the result to xenstore and commit */
+ rc = libxl__xs_write_checked(gc, xt, dom_role_path, "borrower");
+ if (rc) goto out;
+ rc = libxl__xs_writev(gc, xt, borrower_path, ents);
+ if (rc) goto out;
+ rc = libxl__sshm_incref(gc, xt, sshm_path);
+ if (rc) goto out;
+
+ rc = libxl__xs_transaction_commit(gc, &xt);
+ if (!rc) break;
+ if (rc < 0) goto out;
+ }
+
+ rc = libxl__sshm_do_map(gc, owner_domid, domid,
+ sshm, &owner_sshm,
+ mapped, &nmapped);
+
+out:
+ if (rc) {
+ /* roll back successfully mapped pages */
+ SSHM_ERROR(domid, sshm->id, "failed to map some pages, cancelling.");
+ for (i = 0; i < nmapped; i++) {
+ xc_domain_remove_from_physmap(CTX->xch, domid, mapped[i]);
+ }
+ }
+
+ libxl__xs_transaction_abort(gc, &xt);
+
+ return rc;
+}
+
+static int libxl__sshm_add_owner(libxl__gc *gc, uint32_t domid,
+ libxl_static_shm *sshm)
+{
+ int rc;
+ const char *sshm_path, *dom_path, *dom_role_path;
+ const char *xs_value;
+ char *ents[13];
+ struct xs_permissions noperm;
+ xs_transaction_t xt = XBT_NULL;
+
+ sshm_path = SSHM_PATH(sshm->id);
+ dom_path = libxl__xs_get_dompath(gc, domid);
+ /* the domain should be in xenstore by now */
+ assert(dom_path);
+ dom_role_path = GCSPRINTF("%s/static_shm/%s/role", dom_path, sshm->id);
+
+ /* prepare the xenstore entries */
+ ents[0] = "owner";
+ ents[1] = GCSPRINTF("%"PRIu32, domid);
+ ents[2] = "begin";
+ ents[3] = GCSPRINTF("0x%"PRIx64, sshm->begin);
+ ents[4] = "size";
+ ents[5] = GCSPRINTF("0x%"PRIx64, sshm->size);
+ ents[6] = "prot";
+ ents[7] = libxl__strdup(gc,
+ libxl_sshm_prot_to_string(sshm->prot));
+ ents[8] = "cache_policy";
+ ents[9] = libxl__strdup(gc,
+ libxl_sshm_cachepolicy_to_string(sshm->cache_policy));
+ ents[10] = "usercnt";
+ ents[11] = "1";
+ ents[12] = NULL;
+
+ /* could only be accessed by Dom0 */
+ noperm.id = 0;
+ noperm.perms = XS_PERM_NONE;
+
+ for (;;) {
+ rc = libxl__xs_transaction_start(gc, &xt);
+ if (rc) goto out;
+
+ if (!libxl__xs_read_checked(gc, xt, sshm_path, &xs_value)) {
+ /* every ID can appear in each domain at most once */
+ if (libxl__xs_read_checked(gc, xt, dom_role_path, &xs_value)) {
+ SSHM_ERROR(domid, sshm->id,
+ "domain tried to map the same ID twice.");
+ rc = ERROR_FAIL;
+ goto out;
+ }
+ rc = libxl__xs_write_checked(gc, xt, dom_role_path, "owner");
+ if (rc) goto out;;
+
+ libxl__xs_mknod(gc, xt, sshm_path, &noperm, 1);
+ libxl__xs_writev(gc, xt, sshm_path, ents);
+ } else {
+ SSHM_ERROR(domid, sshm->id, "can only have one owner.");
+ rc = ERROR_FAIL;
+ goto out;
+ }
+
+ rc = libxl__xs_transaction_commit(gc, &xt);
+ if (!rc) break;
+ if (rc < 0) goto out;
+ }
+
+ rc = 0;
+out:
+ libxl__xs_transaction_abort(gc, &xt);
+ return rc;
+}
+
+int libxl__sshm_add(libxl__gc *gc, uint32_t domid,
+ libxl_static_shm *sshms, int len)
+{
+ int rc, i;
+
+ for (i = 0; i < len; ++i) {
+ if (sshms[i].role == LIBXL_SSHM_ROLE_BORROWER) {
+ rc = libxl__sshm_add_borrower(gc, domid, sshms+i);
+ } else {
+ rc = libxl__sshm_add_owner(gc, domid, sshms+i);
+ }
+ if (rc) return rc;
+ }
+
+ return 0;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
projects / people / sstabellini / xen-unstable.git / .git / commitdiff