@@ -16,6 +16,51 @@
#include "vm_mgr.h"
+/**
+ * struct gunyah_gmem_binding - Represents a binding of guestmem to a Gunyah VM
+ * @gfn: Guest address to place acquired folios
+ * @ghvm: Pointer to Gunyah VM in this binding
+ * @i_off: offset into the guestmem to grab folios from
+ * @file: Pointer to guest_memfd
+ * @i_entry: list entry for inode->i_private_list
+ * @flags: Access flags for the binding
+ * @nr: Number of pages covered by this binding
+ */
+struct gunyah_gmem_binding {
+ u64 gfn;
+ struct gunyah_vm *ghvm;
+
+ pgoff_t i_off;
+ struct file *file;
+ struct list_head i_entry;
+
+ u32 flags;
+ unsigned long nr;
+};
+
+static inline pgoff_t gunyah_gfn_to_off(struct gunyah_gmem_binding *b, u64 gfn)
+{
+ return gfn - b->gfn + b->i_off;
+}
+
+static inline u64 gunyah_off_to_gfn(struct gunyah_gmem_binding *b, pgoff_t off)
+{
+ return off - b->i_off + b->gfn;
+}
+
+static inline bool gunyah_guest_mem_is_lend(struct gunyah_vm *ghvm, u32 flags)
+{
+ u8 access = flags & GUNYAH_MEM_ACCESS_MASK;
+
+ if (access == GUNYAH_MEM_FORCE_LEND)
+ return true;
+ else if (access == GUNYAH_MEM_FORCE_SHARE)
+ return false;
+
+ /* RM requires all VMs to be protected (isolated) */
+ return true;
+}
+
static struct folio *gunyah_gmem_get_huge_folio(struct inode *inode,
pgoff_t index)
{
@@ -83,6 +128,38 @@ static struct folio *gunyah_gmem_get_folio(struct inode *inode, pgoff_t index)
return folio;
}
+/**
+ * gunyah_gmem_launder_folio() - Tries to unmap one folio from virtual machine(s)
+ * @folio: The folio to unmap
+ *
+ * Returns - 0 if the folio has been reclaimed from any virtual machine(s) that
+ * folio was mapped into.
+ */
+static int gunyah_gmem_launder_folio(struct folio *folio)
+{
+ struct address_space *const mapping = folio->mapping;
+ struct gunyah_gmem_binding *b;
+ pgoff_t index = folio_index(folio);
+ int ret = 0;
+ u64 gfn;
+
+ filemap_invalidate_lock_shared(mapping);
+ list_for_each_entry(b, &mapping->i_private_list, i_entry) {
+ /* if the mapping doesn't cover this folio: skip */
+ if (b->i_off > index || index > b->i_off + b->nr)
+ continue;
+
+ gfn = gunyah_off_to_gfn(b, index);
+ ret = gunyah_vm_reclaim_folio(b->ghvm, gfn, folio);
+ if (WARN_RATELIMIT(ret, "failed to reclaim gfn: %08llx %d\n",
+ gfn, ret))
+ break;
+ }
+ filemap_invalidate_unlock_shared(mapping);
+
+ return ret;
+}
+
static vm_fault_t gunyah_gmem_host_fault(struct vm_fault *vmf)
{
struct folio *folio;
@@ -92,6 +169,15 @@ static vm_fault_t gunyah_gmem_host_fault(struct vm_fault *vmf)
if (!folio)
return VM_FAULT_SIGBUS;
+ /* If the folio is lent to a VM, try to reclaim it */
+ if (folio_test_private(folio) && gunyah_gmem_launder_folio(folio)) {
+ folio_unlock(folio);
+ folio_put(folio);
+ return VM_FAULT_SIGBUS;
+ }
+ /* gunyah_gmem_launder_folio should clear the private bit if it returns 0 */
+ BUG_ON(folio_test_private(folio));
+
vmf->page = folio_file_page(folio, vmf->pgoff);
return VM_FAULT_LOCKED;
@@ -103,9 +189,48 @@ static const struct vm_operations_struct gunyah_gmem_vm_ops = {
static int gunyah_gmem_mmap(struct file *file, struct vm_area_struct *vma)
{
- file_accessed(file);
- vma->vm_ops = &gunyah_gmem_vm_ops;
- return 0;
+ struct address_space *const mapping = file->f_mapping;
+ struct gunyah_gmem_binding *b;
+ pgoff_t end_off;
+ int ret = 0;
+ u64 gfn, nr;
+
+ /* No support for private mappings to avoid COW. */
+ if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) !=
+ (VM_SHARED | VM_MAYSHARE)) {
+ return -EINVAL;
+ }
+
+ filemap_invalidate_lock_shared(mapping);
+ /**
+ * userspace can only mmap if the folios covered by the requested
+ * offset are not lent to the guest
+ */
+ list_for_each_entry(b, &mapping->i_private_list, i_entry) {
+ if (!gunyah_guest_mem_is_lend(b->ghvm, b->flags))
+ continue;
+
+ /* if the binding doesn't cover this vma: skip */
+ if (vma->vm_pgoff + vma_pages(vma) < b->i_off)
+ continue;
+ if (vma->vm_pgoff > b->i_off + b->nr)
+ continue;
+
+ gfn = gunyah_off_to_gfn(b, vma->vm_pgoff);
+ end_off = max(vma->vm_pgoff + vma_pages(vma), b->i_off + b->nr);
+ nr = gunyah_off_to_gfn(b, end_off) - gfn;
+ ret = gunyah_vm_reclaim_range(b->ghvm, gfn, nr);
+ if (ret)
+ break;
+ }
+ filemap_invalidate_unlock_shared(mapping);
+
+ if (!ret) {
+ file_accessed(file);
+ vma->vm_ops = &gunyah_gmem_vm_ops;
+ }
+
+ return ret;
}
/**
@@ -122,9 +247,7 @@ static int gunyah_gmem_mmap(struct file *file, struct vm_area_struct *vma)
static long gunyah_gmem_punch_hole(struct inode *inode, loff_t offset,
loff_t len)
{
- truncate_inode_pages_range(inode->i_mapping, offset, offset + len - 1);
-
- return 0;
+ return invalidate_inode_pages2_range(inode->i_mapping, offset, offset + len - 1);
}
static long gunyah_gmem_allocate(struct inode *inode, loff_t offset, loff_t len)
@@ -201,6 +324,12 @@ static long gunyah_gmem_fallocate(struct file *file, int mode, loff_t offset,
static int gunyah_gmem_release(struct inode *inode, struct file *file)
{
+ /**
+ * each binding increments refcount on file, so we shouldn't be here
+ * if i_private_list not empty.
+ */
+ BUG_ON(!list_empty(&inode->i_mapping->i_private_list));
+
return 0;
}
@@ -213,10 +342,26 @@ static const struct file_operations gunyah_gmem_fops = {
.release = gunyah_gmem_release,
};
+static bool gunyah_gmem_release_folio(struct folio *folio, gfp_t gfp_flags)
+{
+ /* should return true if released; launder folio returns 0 if freed */
+ return !gunyah_gmem_launder_folio(folio);
+}
+
+static int gunyah_gmem_remove_folio(struct address_space *mapping,
+ struct folio *folio)
+{
+ if (mapping != folio->mapping)
+ return -EINVAL;
+
+ return gunyah_gmem_launder_folio(folio);
+}
+
static const struct address_space_operations gunyah_gmem_aops = {
.dirty_folio = noop_dirty_folio,
- .migrate_folio = migrate_folio,
- .error_remove_folio = generic_error_remove_folio,
+ .release_folio = gunyah_gmem_release_folio,
+ .launder_folio = gunyah_gmem_launder_folio,
+ .error_remove_folio = gunyah_gmem_remove_folio,
};
int gunyah_guest_mem_create(struct gunyah_create_mem_args *args)
@@ -264,6 +409,7 @@ int gunyah_guest_mem_create(struct gunyah_create_mem_args *args)
mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
mapping_set_large_folios(inode->i_mapping);
mapping_set_unmovable(inode->i_mapping);
+ mapping_set_release_always(inode->i_mapping);
/* Unmovable mappings are supposed to be marked unevictable as well. */
WARN_ON_ONCE(!mapping_unevictable(inode->i_mapping));
@@ -274,3 +420,267 @@ int gunyah_guest_mem_create(struct gunyah_create_mem_args *args)
put_unused_fd(fd);
return err;
}
+
+void gunyah_gmem_remove_binding(struct gunyah_gmem_binding *b)
+{
+ WARN_ON(gunyah_vm_reclaim_range(b->ghvm, b->gfn, b->nr));
+ mtree_erase(&b->ghvm->bindings, b->gfn);
+ list_del(&b->i_entry);
+ fput(b->file);
+ kfree(b);
+}
+
+static inline unsigned long gunyah_gmem_page_mask(struct file *file)
+{
+ unsigned long gmem_flags = (unsigned long)file_inode(file)->i_private;
+
+ if (gmem_flags & GHMF_ALLOW_HUGEPAGE) {
+#if IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)
+ return HPAGE_PMD_MASK;
+#else
+ return ULONG_MAX;
+#endif
+ }
+
+ return PAGE_MASK;
+}
+
+static int gunyah_gmem_init_binding(struct gunyah_vm *ghvm, struct file *file,
+ struct gunyah_map_mem_args *args,
+ struct gunyah_gmem_binding *binding)
+{
+ const unsigned long page_mask = ~gunyah_gmem_page_mask(file);
+
+ if (args->flags & ~(GUNYAH_MEM_ALLOW_RWX | GUNYAH_MEM_ACCESS_MASK))
+ return -EINVAL;
+
+ if (args->guest_addr & page_mask)
+ return -EINVAL;
+
+ if (args->offset & page_mask)
+ return -EINVAL;
+
+ if (args->size & page_mask)
+ return -EINVAL;
+
+ binding->gfn = gunyah_gpa_to_gfn(args->guest_addr);
+ binding->ghvm = ghvm;
+ binding->i_off = args->offset >> PAGE_SHIFT;
+ binding->file = file;
+ binding->flags = args->flags;
+ binding->nr = args->size >> PAGE_SHIFT;
+
+ return 0;
+}
+
+static int gunyah_gmem_trim_binding(struct gunyah_gmem_binding *b,
+ unsigned long start_delta,
+ unsigned long end_delta)
+{
+ struct gunyah_vm *ghvm = b->ghvm;
+ int ret;
+
+ down_write(&ghvm->bindings_lock);
+ if (!start_delta && !end_delta) {
+ ret = gunyah_vm_reclaim_range(ghvm, b->gfn, b->nr);
+ if (ret)
+ goto unlock;
+ gunyah_gmem_remove_binding(b);
+ } else if (start_delta && !end_delta) {
+ /* keep the start */
+ ret = gunyah_vm_reclaim_range(ghvm, b->gfn + start_delta,
+ b->gfn + b->nr);
+ if (ret)
+ goto unlock;
+ mtree_erase(&ghvm->bindings, b->gfn);
+ b->nr = start_delta;
+ ret = mtree_insert_range(&ghvm->bindings, b->gfn,
+ b->gfn + b->nr - 1, b, GFP_KERNEL);
+ } else if (!start_delta && end_delta) {
+ /* keep the end */
+ ret = gunyah_vm_reclaim_range(ghvm, b->gfn,
+ b->gfn + b->nr - end_delta);
+ if (ret)
+ goto unlock;
+ mtree_erase(&ghvm->bindings, b->gfn);
+ b->gfn += b->nr - end_delta;
+ b->i_off += b->nr - end_delta;
+ b->nr = end_delta;
+ ret = mtree_insert_range(&ghvm->bindings, b->gfn,
+ b->gfn + b->nr - 1, b, GFP_KERNEL);
+ } else {
+ /* TODO: split the mapping into 2 */
+ ret = -EINVAL;
+ }
+
+unlock:
+ up_write(&ghvm->bindings_lock);
+ return ret;
+}
+
+static int gunyah_gmem_remove_mapping(struct gunyah_vm *ghvm, struct file *file,
+ struct gunyah_map_mem_args *args)
+{
+ struct inode *inode = file_inode(file);
+ struct gunyah_gmem_binding *b = NULL;
+ unsigned long start_delta, end_delta;
+ struct gunyah_gmem_binding remove;
+ int ret;
+
+ ret = gunyah_gmem_init_binding(ghvm, file, args, &remove);
+ if (ret)
+ return ret;
+
+ ret = -ENOENT;
+ filemap_invalidate_lock(inode->i_mapping);
+ list_for_each_entry(b, &inode->i_mapping->i_private_list, i_entry) {
+ if (b->ghvm != remove.ghvm || b->flags != remove.flags ||
+ WARN_ON(b->file != remove.file))
+ continue;
+ /**
+ * Test if the binding to remove is within this binding
+ * [gfn b nr]
+ * [gfn remove nr]
+ */
+ if (b->gfn > remove.gfn)
+ continue;
+ if (b->gfn + b->nr < remove.gfn + remove.nr)
+ continue;
+
+ /**
+ * We found the binding!
+ * Compute the delta in gfn start and make sure the offset
+ * into guest memfd matches.
+ */
+ start_delta = remove.gfn - b->gfn;
+ if (remove.i_off - b->i_off != start_delta)
+ break;
+ end_delta = b->gfn + b->nr - remove.gfn - remove.nr;
+
+ ret = gunyah_gmem_trim_binding(b, start_delta, end_delta);
+ break;
+ }
+
+ filemap_invalidate_unlock(inode->i_mapping);
+ return ret;
+}
+
+static bool gunyah_gmem_binding_overlaps(struct gunyah_gmem_binding *a,
+ struct gunyah_gmem_binding *b)
+{
+ /* assumes we are operating on the same file, check to be sure */
+ BUG_ON(a->file != b->file);
+
+ /**
+ * Gunyah only guarantees we can share a page with one VM and
+ * doesn't (currently) allow us to share same page with multiple VMs,
+ * regardless whether host can also access.
+ * Gunyah supports, but Linux hasn't implemented mapping same page
+ * into 2 separate addresses in guest's address space. This doesn't
+ * seem reasonable today, but we could do it later.
+ * All this to justify: check that the `a` region doesn't overlap with
+ * `b` region w.r.t. file offsets.
+ */
+ if (a->i_off + a->nr <= b->i_off)
+ return false;
+ if (a->i_off >= b->i_off + b->nr)
+ return false;
+
+ return true;
+}
+
+static int gunyah_gmem_add_mapping(struct gunyah_vm *ghvm, struct file *file,
+ struct gunyah_map_mem_args *args)
+{
+ struct gunyah_gmem_binding *b, *tmp = NULL;
+ struct inode *inode = file_inode(file);
+ int ret;
+
+ b = kzalloc(sizeof(*b), GFP_KERNEL);
+ if (!b)
+ return -ENOMEM;
+
+ ret = gunyah_gmem_init_binding(ghvm, file, args, b);
+ if (ret)
+ return ret;
+
+ /**
+ * When lending memory, we need to unmap single page from kernel's
+ * logical map. To do that, we need can_set_direct_map().
+ * arm64 doesn't map at page granularity without rodata=full.
+ */
+ if (gunyah_guest_mem_is_lend(ghvm, b->flags) && !can_set_direct_map()) {
+ kfree(b);
+ pr_warn_once("Cannot lend memory without rodata=full");
+ return -EINVAL;
+ }
+
+ /**
+ * First, check that the region of guets memfd user is binding isn't
+ * already bound to some other guest region.
+ */
+ filemap_invalidate_lock(inode->i_mapping);
+ list_for_each_entry(tmp, &inode->i_mapping->i_private_list, i_entry) {
+ if (gunyah_gmem_binding_overlaps(b, tmp)) {
+ ret = -EEXIST;
+ goto unlock;
+ }
+ }
+
+ /**
+ * mtree_insert_range will check that user hasn't mapped some other guest
+ * memfd region to the same addresses.
+ */
+ ret = mtree_insert_range(&ghvm->bindings, b->gfn, b->gfn + b->nr - 1, b,
+ GFP_KERNEL);
+ if (ret)
+ goto unlock;
+
+ list_add(&b->i_entry, &inode->i_mapping->i_private_list);
+
+unlock:
+ filemap_invalidate_unlock(inode->i_mapping);
+ return ret;
+}
+
+int gunyah_gmem_modify_mapping(struct gunyah_vm *ghvm,
+ struct gunyah_map_mem_args *args)
+{
+ u8 access = args->flags & GUNYAH_MEM_ACCESS_MASK;
+ struct file *file;
+ int ret = -EINVAL;
+
+ file = fget(args->guest_mem_fd);
+ if (!file)
+ return -EINVAL;
+
+ if (file->f_op != &gunyah_gmem_fops)
+ goto err_file;
+
+ if (args->flags & ~(GUNYAH_MEM_ALLOW_RWX | GUNYAH_MEM_UNMAP | GUNYAH_MEM_ACCESS_MASK))
+ goto err_file;
+
+ /* VM needs to have some permissions to the memory */
+ if (!(args->flags & GUNYAH_MEM_ALLOW_RWX))
+ goto err_file;
+
+ if (access != GUNYAH_MEM_DEFAULT_ACCESS &&
+ access != GUNYAH_MEM_FORCE_LEND && access != GUNYAH_MEM_FORCE_SHARE)
+ goto err_file;
+
+ if (!PAGE_ALIGNED(args->guest_addr) || !PAGE_ALIGNED(args->offset) ||
+ !PAGE_ALIGNED(args->size))
+ goto err_file;
+
+ if (args->flags & GUNYAH_MEM_UNMAP) {
+ args->flags &= ~GUNYAH_MEM_UNMAP;
+ ret = gunyah_gmem_remove_mapping(ghvm, file, args);
+ } else {
+ ret = gunyah_gmem_add_mapping(ghvm, file, args);
+ }
+
+err_file:
+ if (ret)
+ fput(file);
+ return ret;
+}
@@ -404,6 +404,8 @@ static __must_check struct gunyah_vm *gunyah_vm_alloc(struct gunyah_rm *rm)
INIT_LIST_HEAD(&ghvm->resource_tickets);
mt_init(&ghvm->mm);
+ mt_init(&ghvm->bindings);
+ init_rwsem(&ghvm->bindings_lock);
ghvm->addrspace_ticket.resource_type = GUNYAH_RESOURCE_TYPE_ADDR_SPACE;
ghvm->addrspace_ticket.label = GUNYAH_VM_ADDRSPACE_LABEL;
@@ -556,6 +558,14 @@ static long gunyah_vm_ioctl(struct file *filp, unsigned int cmd,
r = gunyah_vm_rm_function_instance(ghvm, &f);
break;
}
+ case GUNYAH_VM_MAP_MEM: {
+ struct gunyah_map_mem_args args;
+
+ if (copy_from_user(&args, argp, sizeof(args)))
+ return -EFAULT;
+
+ return gunyah_gmem_modify_mapping(ghvm, &args);
+ }
default:
r = -ENOTTY;
break;
@@ -573,6 +583,8 @@ EXPORT_SYMBOL_GPL(gunyah_vm_get);
static void _gunyah_vm_put(struct kref *kref)
{
struct gunyah_vm *ghvm = container_of(kref, struct gunyah_vm, kref);
+ struct gunyah_gmem_binding *b;
+ unsigned long idx = 0;
int ret;
/**
@@ -584,6 +596,13 @@ static void _gunyah_vm_put(struct kref *kref)
gunyah_vm_remove_functions(ghvm);
+ down_write(&ghvm->bindings_lock);
+ mt_for_each(&ghvm->bindings, b, idx, ULONG_MAX) {
+ gunyah_gmem_remove_binding(b);
+ }
+ up_write(&ghvm->bindings_lock);
+ WARN_ON(!mtree_empty(&ghvm->bindings));
+ mtree_destroy(&ghvm->bindings);
/**
* If this fails, we're going to lose the memory for good and is
* BUG_ON-worthy, but not unrecoverable (we just lose memory).
@@ -615,6 +634,7 @@ static void _gunyah_vm_put(struct kref *kref)
/* clang-format on */
}
+ WARN_ON(!mtree_empty(&ghvm->mm));
mtree_destroy(&ghvm->mm);
if (ghvm->vm_status > GUNYAH_RM_VM_STATUS_NO_STATE) {
@@ -38,6 +38,9 @@ long gunyah_dev_vm_mgr_ioctl(struct gunyah_rm *rm, unsigned int cmd,
* @mm: A maple tree of all memory that has been mapped to a VM.
* Indices are guest frame numbers; entries are either folios or
* RM mem parcels
+ * @bindings: A maple tree of guest memfd bindings. Indices are guest frame
+ * numbers; entries are &struct gunyah_gmem_binding
+ * @bindings_lock: For serialization to @bindings
* @addrspace_ticket: Resource ticket to the capability for guest VM's
* address space
* @host_private_extent_ticket: Resource ticket to the capability for our
@@ -77,6 +80,8 @@ long gunyah_dev_vm_mgr_ioctl(struct gunyah_rm *rm, unsigned int cmd,
struct gunyah_vm {
u16 vmid;
struct maple_tree mm;
+ struct maple_tree bindings;
+ struct rw_semaphore bindings_lock;
struct gunyah_vm_resource_ticket addrspace_ticket,
host_private_extent_ticket, host_shared_extent_ticket,
guest_private_extent_ticket, guest_shared_extent_ticket;
@@ -172,5 +177,9 @@ int gunyah_vm_reclaim_folio(struct gunyah_vm *ghvm, u64 gfn, struct folio *folio
int gunyah_vm_reclaim_range(struct gunyah_vm *ghvm, u64 gfn, u64 nr);
int gunyah_guest_mem_create(struct gunyah_create_mem_args *args);
+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);
#endif
@@ -87,6 +87,47 @@ struct gunyah_fn_desc {
#define GUNYAH_VM_ADD_FUNCTION _IOW(GUNYAH_IOCTL_TYPE, 0x4, struct gunyah_fn_desc)
#define GUNYAH_VM_REMOVE_FUNCTION _IOW(GUNYAH_IOCTL_TYPE, 0x7, struct gunyah_fn_desc)
+/**
+ * enum gunyah_map_flags- Possible flags on &struct gunyah_map_mem_args
+ * @GUNYAH_MEM_DEFAULT_SHARE: Use default host access for the VM type
+ * @GUNYAH_MEM_FORCE_LEND: Force unmapping the memory once the guest starts to use
+ * @GUNYAH_MEM_FORCE_SHARE: Allow host to continue accessing memory when guest starts to use
+ * @GUNYAH_MEM_ALLOW_READ: Allow guest to read memory
+ * @GUNYAH_MEM_ALLOW_WRITE: Allow guest to write to the memory
+ * @GUNYAH_MEM_ALLOW_EXEC: Allow guest to execute instructions in the memory
+ */
+enum gunyah_map_flags {
+ GUNYAH_MEM_DEFAULT_ACCESS = 0,
+ GUNYAH_MEM_FORCE_LEND = 1,
+ GUNYAH_MEM_FORCE_SHARE = 2,
+#define GUNYAH_MEM_ACCESS_MASK 0x7
+
+ GUNYAH_MEM_ALLOW_READ = 1UL << 4,
+ GUNYAH_MEM_ALLOW_WRITE = 1UL << 5,
+ GUNYAH_MEM_ALLOW_EXEC = 1UL << 6,
+ GUNYAH_MEM_ALLOW_RWX =
+ (GUNYAH_MEM_ALLOW_READ | GUNYAH_MEM_ALLOW_WRITE | GUNYAH_MEM_ALLOW_EXEC),
+
+ GUNYAH_MEM_UNMAP = 1UL << 8,
+};
+
+/**
+ * struct gunyah_map_mem_args - Description to provide guest memory into a VM
+ * @guest_addr: Location in guest address space to place the memory
+ * @flags: See &enum gunyah_map_flags.
+ * @guest_mem_fd: File descriptor created by GUNYAH_CREATE_GUEST_MEM
+ * @offset: Offset into the guest memory file
+ */
+struct gunyah_map_mem_args {
+ __u64 guest_addr;
+ __u32 flags;
+ __u32 guest_mem_fd;
+ __u64 offset;
+ __u64 size;
+};
+
+#define GUNYAH_VM_MAP_MEM _IOW(GUNYAH_IOCTL_TYPE, 0x9, struct gunyah_map_mem_args)
+
/*
* ioctls for vCPU fds
*/
A maple tree is used to maintain a map from guest address ranges to a guestmemfd that provides the memory for that range of memory for the guest. The mapping of guest address range to guestmemfd is called a binding. Implement an ioctl to add/remove bindings to the virtual machine. The binding determines whether the memory is shared (host retains access) or lent (host loses access). Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> --- drivers/virt/gunyah/guest_memfd.c | 426 +++++++++++++++++++++++++++++++++++++- drivers/virt/gunyah/vm_mgr.c | 20 ++ drivers/virt/gunyah/vm_mgr.h | 9 + include/uapi/linux/gunyah.h | 41 ++++ 4 files changed, 488 insertions(+), 8 deletions(-)