* Steve Sistare (steven.sist...@oracle.com) wrote:
> Allocate anonymous memory using memfd_create if the memfd-alloc machine
> option is set.
>
> Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
So other than the minor error nit that Guoyi spotted, I think this is
pretty good, one other comment below:
> ---
> hw/core/machine.c | 19 +++++++++++++++++++
> include/hw/boards.h | 1 +
> qemu-options.hx | 6 ++++++
> softmmu/physmem.c | 47 ++++++++++++++++++++++++++++++++++++++---------
> softmmu/vl.c | 1 +
> trace-events | 1 +
> util/qemu-config.c | 4 ++++
> 7 files changed, 70 insertions(+), 9 deletions(-)
>
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index 53a99ab..7739d88 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -392,6 +392,20 @@ 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);
> @@ -829,6 +843,11 @@ 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",
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 9c1c190..a57d7a0 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -327,6 +327,7 @@ struct MachineState {
> char *dt_compatible;
> bool dump_guest_core;
> bool mem_merge;
> + bool memfd_alloc;
> bool usb;
> bool usb_disabled;
> char *firmware;
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 7d47510..33c8173 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -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 guest
> RAM 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 +77,11 @@ 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 guest RAM using
> + memfd_create. Any associated memory-backend objects are created with
> + share=on. The memfd-alloc default is off.
> +
> ``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
> diff --git a/softmmu/physmem.c b/softmmu/physmem.c
> index 3524c04..95e2b49 100644
> --- a/softmmu/physmem.c
> +++ b/softmmu/physmem.c
> @@ -41,6 +41,7 @@
> #include "qemu/config-file.h"
> #include "qemu/error-report.h"
> #include "qemu/qemu-print.h"
> +#include "qemu/memfd.h"
> #include "exec/memory.h"
> #include "exec/ioport.h"
> #include "sysemu/dma.h"
> @@ -1964,35 +1965,63 @@ static void ram_block_add(RAMBlock *new_block, Error
> **errp)
> const bool shared = qemu_ram_is_shared(new_block);
> 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;
You could move some of these down to the top of the block you're using
them.
> + 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, noreserve);
> - if (!new_block->host) {
> + name = memory_region_name(mr);
> + if (ms->memfd_alloc) {
> + Object *parent = &mr->parent_obj;
> + 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;
> + }
> + }
> + qemu_set_cloexec(mfd);
> + /* The memory backend already set its desired flags. */
> + if (!object_dynamic_cast(parent, TYPE_MEMORY_BACKEND)) {
> + 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, noreserve);
> + }
> +
> + 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;
> }
> }
>
> diff --git a/softmmu/vl.c b/softmmu/vl.c
> index 620a1f1..ab3648a 100644
> --- a/softmmu/vl.c
> +++ b/softmmu/vl.c
> @@ -2440,6 +2440,7 @@ static void create_default_memdev(MachineState *ms,
> const char *path)
> object_property_set_str(obj, "mem-path", path, &error_fatal);
> }
> object_property_set_int(obj, "size", ms->ram_size, &error_fatal);
> + object_property_set_bool(obj, "share", ms->memfd_alloc, &error_fatal);
> object_property_add_child(object_get_objects_root(), mc->default_ram_id,
> obj);
> /* Ensure backend's memory region name is equal to mc->default_ram_id */
> diff --git a/trace-events b/trace-events
> index a637a61..770a9ac 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -45,6 +45,7 @@ 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"
> diff --git a/util/qemu-config.c b/util/qemu-config.c
> index 436ab63..3606e5c 100644
> --- a/util/qemu-config.c
> +++ b/util/qemu-config.c
> @@ -207,6 +207,10 @@ 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",
> --
> 1.8.3.1
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
