@@ -375,6 +375,20 @@ static void machine_set_mem_merge(Object *obj, bool value, Error **errp)
ms->mem_merge = value;
}
+static bool machine_get_memfd_alloc(Object *obj, Error **errp)
+{
+ MachineState *ms = MACHINE(obj);
+
+ return ms->memfd_alloc;
+}
+
+static void machine_set_memfd_alloc(Object *obj, bool value, Error **errp)
+{
+ MachineState *ms = MACHINE(obj);
+
+ ms->memfd_alloc = value;
+}
+
static bool machine_get_usb(Object *obj, Error **errp)
{
MachineState *ms = MACHINE(obj);
@@ -858,6 +872,11 @@ static void machine_class_init(ObjectClass *oc, void *data)
object_class_property_set_description(oc, "mem-merge",
"Enable/disable memory merge support");
+ object_class_property_add_bool(oc, "memfd-alloc",
+ machine_get_memfd_alloc, machine_set_memfd_alloc);
+ object_class_property_set_description(oc, "memfd-alloc",
+ "Enable/disable allocating anonymous memory using memfd_create");
+
object_class_property_add_bool(oc, "usb",
machine_get_usb, machine_set_usb);
object_class_property_set_description(oc, "usb",
@@ -305,6 +305,7 @@ struct MachineState {
char *dt_compatible;
bool dump_guest_core;
bool mem_merge;
+ bool memfd_alloc;
bool usb;
bool usb_disabled;
char *firmware;
@@ -30,6 +30,7 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
" vmport=on|off|auto controls emulation of vmport (default: auto)\n"
" dump-guest-core=on|off include guest memory in a core dump (default=on)\n"
" mem-merge=on|off controls memory merge support (default: on)\n"
+ " memfd-alloc=on|off controls allocating anonymous memory using memfd_create (default: off)\n"
" aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n"
" dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n"
" suppress-vmdesc=on|off disables self-describing migration (default=off)\n"
@@ -76,6 +77,10 @@ SRST
supported by the host, de-duplicates identical memory pages
among VMs instances (enabled by default).
+ ``memfd-alloc=on|off``
+ Enables or disables allocation of anonymous memory using memfd_create.
+ (disabled by default).
+
``aes-key-wrap=on|off``
Enables or disables AES key wrapping support on s390-ccw hosts.
This feature controls whether AES wrapping keys will be created
@@ -67,6 +67,7 @@
#include "qemu/pmem.h"
+#include "qemu/memfd.h"
#include "migration/vmstate.h"
#include "qemu/range.h"
@@ -1931,35 +1932,57 @@ static void ram_block_add(RAMBlock *new_block, Error **errp, bool shared)
{
RAMBlock *block;
RAMBlock *last_block = NULL;
+ struct MemoryRegion *mr = new_block->mr;
ram_addr_t old_ram_size, new_ram_size;
Error *err = NULL;
+ const char *name;
+ void *addr = 0;
+ size_t maxlen;
+ MachineState *ms = MACHINE(qdev_get_machine());
old_ram_size = last_ram_page();
qemu_mutex_lock_ramlist();
- new_block->offset = find_ram_offset(new_block->max_length);
+ maxlen = new_block->max_length;
+ new_block->offset = find_ram_offset(maxlen);
if (!new_block->host) {
if (xen_enabled()) {
- xen_ram_alloc(new_block->offset, new_block->max_length,
- new_block->mr, &err);
+ xen_ram_alloc(new_block->offset, maxlen, new_block->mr, &err);
if (err) {
error_propagate(errp, err);
qemu_mutex_unlock_ramlist();
return;
}
} else {
- new_block->host = qemu_anon_ram_alloc(new_block->max_length,
- &new_block->mr->align,
- shared);
- if (!new_block->host) {
+ name = memory_region_name(new_block->mr);
+ if (ms->memfd_alloc) {
+ int mfd = -1; /* placeholder until next patch */
+ mr->align = QEMU_VMALLOC_ALIGN;
+ if (mfd < 0) {
+ mfd = qemu_memfd_create(name, maxlen + mr->align,
+ 0, 0, 0, &err);
+ if (mfd < 0) {
+ return;
+ }
+ }
+ new_block->flags |= RAM_SHARED;
+ addr = file_ram_alloc(new_block, maxlen, mfd,
+ false, false, 0, errp);
+ trace_anon_memfd_alloc(name, maxlen, addr, mfd);
+ } else {
+ addr = qemu_anon_ram_alloc(maxlen, &mr->align, shared);
+ }
+
+ if (!addr) {
error_setg_errno(errp, errno,
"cannot set up guest memory '%s'",
- memory_region_name(new_block->mr));
+ name);
qemu_mutex_unlock_ramlist();
return;
}
- memory_try_enable_merging(new_block->host, new_block->max_length);
+ memory_try_enable_merging(addr, maxlen);
+ new_block->host = addr;
}
}
@@ -40,6 +40,7 @@ ram_block_discard_range(const char *rbname, void *hva, size_t length, bool need_
# accel/tcg/cputlb.c
memory_notdirty_write_access(uint64_t vaddr, uint64_t ram_addr, unsigned size) "0x%" PRIx64 " ram_addr 0x%" PRIx64 " size %u"
memory_notdirty_set_dirty(uint64_t vaddr) "0x%" PRIx64
+anon_memfd_alloc(const char *name, size_t size, void *ptr, int fd) "%s size %zu ptr %p fd %d"
# gdbstub.c
gdbstub_op_start(const char *device) "Starting gdbstub using device %s"
@@ -205,6 +205,10 @@ static QemuOptsList machine_opts = {
.type = QEMU_OPT_BOOL,
.help = "enable/disable memory merge support",
},{
+ .name = "memfd-alloc",
+ .type = QEMU_OPT_BOOL,
+ .help = "enable/disable memfd_create for anonymous memory",
+ },{
.name = "usb",
.type = QEMU_OPT_BOOL,
.help = "Set on/off to enable/disable usb",
Allocate anonymous memory using memfd_create if the memfd-alloc machine option is set. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> --- hw/core/machine.c | 19 +++++++++++++++++++ include/hw/boards.h | 1 + qemu-options.hx | 5 +++++ softmmu/physmem.c | 41 ++++++++++++++++++++++++++++++++--------- trace-events | 1 + util/qemu-config.c | 4 ++++ 6 files changed, 62 insertions(+), 9 deletions(-)