First stage of hugetlb support: add initialization and cleanup
routines
Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
---
include/uapi/linux/kvm.h | 25 ++++++++++++
virt/kvm/guest_mem.c | 88 +++++++++++++++++++++++++++++++++++++---
2 files changed, 108 insertions(+), 5 deletions(-)
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 0fa665e8862a..1df0c802c29f 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -13,6 +13,7 @@
#include <linux/compiler.h>
#include <linux/ioctl.h>
#include <asm/kvm.h>
+#include <asm-generic/hugetlb_encode.h>
#define KVM_API_VERSION 12
@@ -2280,6 +2281,30 @@ struct kvm_memory_attributes {
#define KVM_CREATE_GUEST_MEMFD _IOWR(KVMIO, 0xd4, struct kvm_create_guest_memfd)
#define KVM_GUEST_MEMFD_HUGE_PMD (1ULL << 0)
+#define KVM_GUEST_MEMFD_HUGETLB (1ULL << 1)
+
+/*
+ * Huge page size encoding when KVM_GUEST_MEMFD_HUGETLB is specified, and a huge
+ * page size other than the default is desired. See hugetlb_encode.h. All
+ * known huge page size encodings are provided here. It is the responsibility
+ * of the application to know which sizes are supported on the running system.
+ * See mmap(2) man page for details.
+ */
+#define KVM_GUEST_MEMFD_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT
+#define KVM_GUEST_MEMFD_HUGE_MASK HUGETLB_FLAG_ENCODE_MASK
+
+#define KVM_GUEST_MEMFD_HUGE_64KB HUGETLB_FLAG_ENCODE_64KB
+#define KVM_GUEST_MEMFD_HUGE_512KB HUGETLB_FLAG_ENCODE_512KB
+#define KVM_GUEST_MEMFD_HUGE_1MB HUGETLB_FLAG_ENCODE_1MB
+#define KVM_GUEST_MEMFD_HUGE_2MB HUGETLB_FLAG_ENCODE_2MB
+#define KVM_GUEST_MEMFD_HUGE_8MB HUGETLB_FLAG_ENCODE_8MB
+#define KVM_GUEST_MEMFD_HUGE_16MB HUGETLB_FLAG_ENCODE_16MB
+#define KVM_GUEST_MEMFD_HUGE_32MB HUGETLB_FLAG_ENCODE_32MB
+#define KVM_GUEST_MEMFD_HUGE_256MB HUGETLB_FLAG_ENCODE_256MB
+#define KVM_GUEST_MEMFD_HUGE_512MB HUGETLB_FLAG_ENCODE_512MB
+#define KVM_GUEST_MEMFD_HUGE_1GB HUGETLB_FLAG_ENCODE_1GB
+#define KVM_GUEST_MEMFD_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB
+#define KVM_GUEST_MEMFD_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB
struct kvm_create_guest_memfd {
__u64 size;
diff --git a/virt/kvm/guest_mem.c b/virt/kvm/guest_mem.c
index 13253af40be6..b533143e2878 100644
--- a/virt/kvm/guest_mem.c
+++ b/virt/kvm/guest_mem.c
@@ -19,6 +19,7 @@
#include <linux/secretmem.h>
#include <linux/set_memory.h>
#include <linux/sched/signal.h>
+#include <linux/hugetlb.h>
#include <uapi/linux/magic.h>
@@ -30,6 +31,11 @@ struct kvm_gmem {
struct kvm *kvm;
u64 flags;
struct xarray bindings;
+ struct {
+ struct hstate *h;
+ struct hugepage_subpool *spool;
+ struct resv_map *resv_map;
+ } hugetlb;
};
static loff_t kvm_gmem_get_size(struct file *file)
@@ -346,6 +352,46 @@ static const struct inode_operations kvm_gmem_iops = {
.setattr = kvm_gmem_setattr,
};
+static int kvm_gmem_hugetlb_setup(struct inode *inode, struct kvm_gmem *gmem,
+ loff_t size, u64 flags)
+{
+ int page_size_log;
+ int hstate_idx;
+ long hpages;
+ struct resv_map *resv_map;
+ struct hugepage_subpool *spool;
+ struct hstate *h;
+
+ page_size_log = (flags >> KVM_GUEST_MEMFD_HUGE_SHIFT) & KVM_GUEST_MEMFD_HUGE_MASK;
+ hstate_idx = get_hstate_idx(page_size_log);
+ if (hstate_idx < 0)
+ return -ENOENT;
+
+ h = &hstates[hstate_idx];
+ /* Round up to accommodate size requests that don't align with huge pages */
+ hpages = round_up(size, huge_page_size(h)) >> huge_page_shift(h);
+ spool = hugepage_new_subpool(h, hpages, hpages);
+ if (!spool)
+ goto out;
+
+ resv_map = resv_map_alloc();
+ if (!resv_map)
+ goto out_subpool;
+
+ inode->i_blkbits = huge_page_shift(h);
+
+ gmem->hugetlb.h = h;
+ gmem->hugetlb.spool = spool;
+ gmem->hugetlb.resv_map = resv_map;
+
+ return 0;
+
+out_subpool:
+ kfree(spool);
+out:
+ return -ENOMEM;
+}
+
static struct inode *kvm_gmem_create_inode(struct kvm *kvm, loff_t size, u64 flags,
struct vfsmount *mnt)
{
@@ -368,6 +414,12 @@ static struct inode *kvm_gmem_create_inode(struct kvm *kvm, loff_t size, u64 fla
if (!gmem)
goto err_inode;
+ if (flags & KVM_GUEST_MEMFD_HUGETLB) {
+ err = kvm_gmem_hugetlb_setup(inode, gmem, size, flags);
+ if (err)
+ goto err_gmem;
+ }
+
xa_init(&gmem->bindings);
kvm_get_kvm(kvm);
@@ -385,6 +437,8 @@ static struct inode *kvm_gmem_create_inode(struct kvm *kvm, loff_t size, u64 fla
return inode;
+err_gmem:
+ kfree(gmem);
err_inode:
iput(inode);
return ERR_PTR(err);
@@ -414,6 +468,8 @@ static struct file *kvm_gmem_create_file(struct kvm *kvm, loff_t size, u64 flags
return file;
}
+#define KVM_GUEST_MEMFD_ALL_FLAGS (KVM_GUEST_MEMFD_HUGE_PMD | KVM_GUEST_MEMFD_HUGETLB)
+
int kvm_gmem_create(struct kvm *kvm, struct kvm_create_guest_memfd *gmem)
{
int fd;
@@ -424,8 +480,15 @@ int kvm_gmem_create(struct kvm *kvm, struct kvm_create_guest_memfd *gmem)
if (size < 0 || !PAGE_ALIGNED(size))
return -EINVAL;
- if (flags & ~KVM_GUEST_MEMFD_HUGE_PMD)
- return -EINVAL;
+ if (!(flags & KVM_GUEST_MEMFD_HUGETLB)) {
+ if (flags & ~(unsigned int)KVM_GUEST_MEMFD_ALL_FLAGS)
+ return -EINVAL;
+ } else {
+ /* Allow huge page size encoding in flags. */
+ if (flags & ~(unsigned int)(KVM_GUEST_MEMFD_ALL_FLAGS |
+ (KVM_GUEST_MEMFD_HUGE_MASK << KVM_GUEST_MEMFD_HUGE_SHIFT)))
+ return -EINVAL;
+ }
if (flags & KVM_GUEST_MEMFD_HUGE_PMD) {
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -610,7 +673,17 @@ static void kvm_gmem_evict_inode(struct inode *inode)
* pointed at this file.
*/
kvm_gmem_invalidate_begin(kvm, gmem, 0, -1ul);
- truncate_inode_pages_final(inode->i_mapping);
+ if (gmem->flags & KVM_GUEST_MEMFD_HUGETLB) {
+ truncate_inode_pages_final_prepare(inode->i_mapping);
+ remove_mapping_hugepages(
+ inode->i_mapping, gmem->hugetlb.h, gmem->hugetlb.spool,
+ gmem->hugetlb.resv_map, inode, 0, LLONG_MAX);
+
+ resv_map_release(&gmem->hugetlb.resv_map->refs);
+ hugepage_put_subpool(gmem->hugetlb.spool);
+ } else {
+ truncate_inode_pages_final(inode->i_mapping);
+ }
kvm_gmem_invalidate_end(kvm, gmem, 0, -1ul);
mutex_unlock(&kvm->slots_lock);
@@ -688,10 +761,15 @@ bool kvm_gmem_check_alignment(const struct kvm_userspace_memory_region2 *mem)
{
size_t page_size;
- if (mem->flags & KVM_GUEST_MEMFD_HUGE_PMD)
+ if (mem->flags & KVM_GUEST_MEMFD_HUGETLB) {
+ size_t page_size_log = ((mem->flags >> KVM_GUEST_MEMFD_HUGE_SHIFT)
+ & KVM_GUEST_MEMFD_HUGE_MASK);
+ page_size = 1UL << page_size_log;
+ } else if (mem->flags & KVM_GUEST_MEMFD_HUGE_PMD) {
page_size = HPAGE_PMD_SIZE;
- else
+ } else {
page_size = PAGE_SIZE;
+ }
return (IS_ALIGNED(mem->gmem_offset, page_size) &&
IS_ALIGNED(mem->memory_size, page_size));
--
2.41.0.rc0.172.g3f132b7071-goog
