Gunyah Resource Manager sets up a virtual machine based on a device
tree which lives in guest memory. Resource manager requires this memory
to be provided as a memory parcel for it to read and manipulate.
Implement a function to construct a memory parcel from a guestmem
binding.
Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
---
drivers/virt/gunyah/guest_memfd.c | 207 ++++++++++++++++++++++++++++++++++++++
drivers/virt/gunyah/vm_mgr.h | 6 ++
2 files changed, 213 insertions(+)
diff --git a/drivers/virt/gunyah/guest_memfd.c b/drivers/virt/gunyah/guest_memfd.c
index d6be8bf67d996..0c35ffa616d9c 100644
--- a/drivers/virt/gunyah/guest_memfd.c
+++ b/drivers/virt/gunyah/guest_memfd.c
@@ -684,3 +684,210 @@ int gunyah_gmem_modify_mapping(struct gunyah_vm *ghvm,
fput(file);
return ret;
}
+
+int gunyah_gmem_share_parcel(struct gunyah_vm *ghvm, struct gunyah_rm_mem_parcel *parcel,
+ u64 *gfn, u64 *nr)
+{
+ struct folio *folio, *prev_folio;
+ unsigned long nr_entries, i, j, start, end;
+ struct gunyah_gmem_binding *b;
+ bool lend;
+ int ret;
+
+ parcel->mem_handle = GUNYAH_MEM_HANDLE_INVAL;
+
+ if (!*nr)
+ return -EINVAL;
+
+ down_read(&ghvm->bindings_lock);
+ b = mtree_load(&ghvm->bindings, *gfn);
+ if (!b || *gfn > b->gfn + b->nr || *gfn < b->gfn) {
+ ret = -ENOENT;
+ goto unlock;
+ }
+
+ /**
+ * Generally, indices can be based on gfn, guest_memfd offset, or
+ * offset into binding. start and end are based on offset into binding.
+ */
+ start = *gfn - b->gfn;
+
+ if (start + *nr > b->nr) {
+ ret = -ENOENT;
+ goto unlock;
+ }
+
+ end = start + *nr;
+ lend = gunyah_guest_mem_is_lend(ghvm, b->flags);
+
+ /**
+ * First, calculate the number of physically discontiguous regions
+ * the parcel covers. Each memory entry corresponds to one folio.
+ * In future, each memory entry could correspond to contiguous
+ * folios that are also adjacent in guest_memfd, but parcels
+ * are only being used for small amounts of memory for now, so
+ * this optimization is premature.
+ */
+ nr_entries = 0;
+ prev_folio = NULL;
+ for (i = start + b->i_off; i < end + b->i_off;) {
+ folio = gunyah_gmem_get_folio(file_inode(b->file), i); /* A */
+ if (!folio) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ if (lend) {
+ /* don't lend a folio that is mapped by host */
+ if (!gunyah_folio_lend_safe(folio)) {
+ folio_unlock(folio);
+ folio_put(folio);
+ ret = -EPERM;
+ goto out;
+ }
+ folio_set_private(folio);
+ }
+
+ nr_entries++;
+ i = folio_index(folio) + folio_nr_pages(folio);
+ }
+ end = i - b->i_off;
+
+ parcel->mem_entries =
+ kcalloc(nr_entries, sizeof(*parcel->mem_entries), GFP_KERNEL);
+ if (!parcel->mem_entries) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ /**
+ * Walk through all the folios again, now filling the mem_entries array.
+ */
+ j = 0;
+ prev_folio = NULL;
+ for (i = start + b->i_off; i < end + b->i_off; j++) {
+ folio = filemap_get_folio(file_inode(b->file)->i_mapping, i); /* B */
+ if (WARN_ON(IS_ERR(folio))) {
+ ret = PTR_ERR(folio);
+ i = end + b->i_off;
+ goto out;
+ }
+
+ parcel->mem_entries[j].size = cpu_to_le64(folio_size(folio));
+ parcel->mem_entries[j].phys_addr = cpu_to_le64(PFN_PHYS(folio_pfn(folio)));
+ i = folio_index(folio) + folio_nr_pages(folio);
+ folio_put(folio); /* B */
+ }
+ BUG_ON(j != nr_entries);
+ parcel->n_mem_entries = nr_entries;
+
+ if (lend)
+ parcel->n_acl_entries = 1;
+
+ parcel->acl_entries = kcalloc(parcel->n_acl_entries,
+ sizeof(*parcel->acl_entries), GFP_KERNEL);
+ if (!parcel->n_acl_entries) {
+ ret = -ENOMEM;
+ goto free_entries;
+ }
+
+ parcel->acl_entries[0].vmid = cpu_to_le16(ghvm->vmid);
+ if (b->flags & GUNYAH_MEM_ALLOW_READ)
+ parcel->acl_entries[0].perms |= GUNYAH_RM_ACL_R;
+ if (b->flags & GUNYAH_MEM_ALLOW_WRITE)
+ parcel->acl_entries[0].perms |= GUNYAH_RM_ACL_W;
+ if (b->flags & GUNYAH_MEM_ALLOW_EXEC)
+ parcel->acl_entries[0].perms |= GUNYAH_RM_ACL_X;
+
+ if (!lend) {
+ u16 host_vmid;
+
+ ret = gunyah_rm_get_vmid(ghvm->rm, &host_vmid);
+ if (ret)
+ goto free_acl;
+
+ parcel->acl_entries[1].vmid = cpu_to_le16(host_vmid);
+ parcel->acl_entries[1].perms = GUNYAH_RM_ACL_R | GUNYAH_RM_ACL_W | GUNYAH_RM_ACL_X;
+ }
+
+ parcel->mem_handle = GUNYAH_MEM_HANDLE_INVAL;
+ folio = filemap_get_folio(file_inode(b->file)->i_mapping, start); /* C */
+ *gfn = folio_index(folio) - b->i_off + b->gfn;
+ *nr = end - (folio_index(folio) - b->i_off);
+ folio_put(folio); /* C */
+
+ ret = gunyah_rm_mem_share(ghvm->rm, parcel);
+ goto out;
+free_acl:
+ kfree(parcel->acl_entries);
+ parcel->acl_entries = NULL;
+free_entries:
+ kfree(parcel->mem_entries);
+ parcel->mem_entries = NULL;
+ parcel->n_mem_entries = 0;
+out:
+ /* unlock the folios */
+ for (j = start + b->i_off; j < i;) {
+ folio = filemap_get_folio(file_inode(b->file)->i_mapping, j); /* D */
+ if (WARN_ON(IS_ERR(folio)))
+ continue;
+ j = folio_index(folio) + folio_nr_pages(folio);
+ folio_unlock(folio); /* A */
+ if (ret) {
+ if (folio_test_private(folio)) {
+ gunyah_folio_host_reclaim(folio);
+ folio_clear_private(folio);
+ }
+ folio_put(folio); /* A */
+ }
+ folio_put(folio); /* D */
+ /* matching folio_put for A is done at
+ * (1) gunyah_gmem_reclaim_parcel or
+ * (2) after gunyah_gmem_parcel_to_paged, gunyah_vm_reclaim_folio
+ */
+ }
+unlock:
+ up_read(&ghvm->bindings_lock);
+ return ret;
+}
+
+int gunyah_gmem_reclaim_parcel(struct gunyah_vm *ghvm,
+ struct gunyah_rm_mem_parcel *parcel, u64 gfn,
+ u64 nr)
+{
+ struct gunyah_rm_mem_entry *entry;
+ struct folio *folio;
+ pgoff_t i;
+ int ret;
+
+ if (parcel->mem_handle != GUNYAH_MEM_HANDLE_INVAL) {
+ ret = gunyah_rm_mem_reclaim(ghvm->rm, parcel);
+ if (ret) {
+ dev_err(ghvm->parent, "Failed to reclaim parcel: %d\n",
+ ret);
+ /* We can't reclaim the pages -- hold onto the pages
+ * forever because we don't know what state the memory
+ * is in
+ */
+ return ret;
+ }
+ parcel->mem_handle = GUNYAH_MEM_HANDLE_INVAL;
+
+ for (i = 0; i < parcel->n_mem_entries; i++) {
+ entry = &parcel->mem_entries[i];
+
+ folio = pfn_folio(PHYS_PFN(le64_to_cpu(entry->phys_addr)));
+
+ if (folio_test_private(folio))
+ gunyah_folio_host_reclaim(folio);
+
+ folio_clear_private(folio);
+ folio_put(folio); /* A */
+ }
+
+ kfree(parcel->mem_entries);
+ kfree(parcel->acl_entries);
+ }
+
+ return 0;
+}
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index d9f101fc52632..b6bc66f018b09 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -181,5 +181,11 @@ int gunyah_gmem_modify_mapping(struct gunyah_vm *ghvm,
struct gunyah_map_mem_args *args);
struct gunyah_gmem_binding;
void gunyah_gmem_remove_binding(struct gunyah_gmem_binding *binding);
+int gunyah_gmem_share_parcel(struct gunyah_vm *ghvm,
+ struct gunyah_rm_mem_parcel *parcel, u64 *gfn,
+ u64 *nr);
+int gunyah_gmem_reclaim_parcel(struct gunyah_vm *ghvm,
+ struct gunyah_rm_mem_parcel *parcel, u64 gfn,
+ u64 nr);
#endif
--
2.34.1
