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-rw-r--r--include/exec/cpu-common.h1
-rw-r--r--include/exec/memory.h15
-rw-r--r--include/exec/ram_addr.h3
-rw-r--r--include/qemu/osdep.h9
-rw-r--r--migration/ram.c3
-rw-r--r--softmmu/physmem.c15
-rw-r--r--util/mmap-alloc.c7
-rw-r--r--util/oslib-posix.c6
-rw-r--r--util/oslib-win32.c13
9 files changed, 59 insertions, 13 deletions
diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index ccabed4..039d422 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -59,6 +59,7 @@ ram_addr_t qemu_ram_get_offset(RAMBlock *rb);
ram_addr_t qemu_ram_get_used_length(RAMBlock *rb);
ram_addr_t qemu_ram_get_max_length(RAMBlock *rb);
bool qemu_ram_is_shared(RAMBlock *rb);
+bool qemu_ram_is_noreserve(RAMBlock *rb);
bool qemu_ram_is_uf_zeroable(RAMBlock *rb);
void qemu_ram_set_uf_zeroable(RAMBlock *rb);
bool qemu_ram_is_migratable(RAMBlock *rb);
diff --git a/include/exec/memory.h b/include/exec/memory.h
index b1f8fa1..b116f7c 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -155,6 +155,13 @@ typedef struct IOMMUTLBEvent {
*/
#define RAM_UF_WRITEPROTECT (1 << 6)
+/*
+ * RAM is mmap-ed with MAP_NORESERVE. When set, reserving swap space (or huge
+ * pages if applicable) is skipped: will bail out if not supported. When not
+ * set, the OS will do the reservation, if supported for the memory type.
+ */
+#define RAM_NORESERVE (1 << 7)
+
static inline void iommu_notifier_init(IOMMUNotifier *n, IOMMUNotify fn,
IOMMUNotifierFlag flags,
hwaddr start, hwaddr end,
@@ -949,7 +956,7 @@ void memory_region_init_ram_nomigrate(MemoryRegion *mr,
* @name: Region name, becomes part of RAMBlock name used in migration stream
* must be unique within any device
* @size: size of the region.
- * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED.
+ * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_NORESERVE.
* @errp: pointer to Error*, to store an error if it happens.
*
* Note that this function does not do anything to cause the data in the
@@ -1005,7 +1012,8 @@ void memory_region_init_resizeable_ram(MemoryRegion *mr,
* @size: size of the region.
* @align: alignment of the region base address; if 0, the default alignment
* (getpagesize()) will be used.
- * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM.
+ * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM,
+ * RAM_NORESERVE,
* @path: the path in which to allocate the RAM.
* @readonly: true to open @path for reading, false for read/write.
* @errp: pointer to Error*, to store an error if it happens.
@@ -1031,7 +1039,8 @@ void memory_region_init_ram_from_file(MemoryRegion *mr,
* @owner: the object that tracks the region's reference count
* @name: the name of the region.
* @size: size of the region.
- * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM.
+ * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM,
+ * RAM_NORESERVE.
* @fd: the fd to mmap.
* @offset: offset within the file referenced by fd
* @errp: pointer to Error*, to store an error if it happens.
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index 6d4513f..551876b 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -104,7 +104,8 @@ long qemu_maxrampagesize(void);
* Parameters:
* @size: the size in bytes of the ram block
* @mr: the memory region where the ram block is
- * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM.
+ * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM,
+ * RAM_NORESERVE.
* @mem_path or @fd: specify the backing file or device
* @readonly: true to open @path for reading, false for read/write.
* @errp: pointer to Error*, to store an error if it happens
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 37a38c4..c2c7fe5 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -362,7 +362,8 @@ extern "C" {
int qemu_daemon(int nochdir, int noclose);
void *qemu_try_memalign(size_t alignment, size_t size);
void *qemu_memalign(size_t alignment, size_t size);
-void *qemu_anon_ram_alloc(size_t size, uint64_t *align, bool shared);
+void *qemu_anon_ram_alloc(size_t size, uint64_t *align, bool shared,
+ bool noreserve);
void qemu_vfree(void *ptr);
void qemu_anon_ram_free(void *ptr, size_t size);
@@ -383,6 +384,12 @@ void qemu_anon_ram_free(void *ptr, size_t size);
*/
#define QEMU_MAP_SYNC (1 << 2)
+/*
+ * Use MAP_NORESERVE to skip reservation of swap space (or huge pages if
+ * applicable). Bail out if not supported/effective.
+ */
+#define QEMU_MAP_NORESERVE (1 << 3)
+
#define QEMU_MADV_INVALID -1
diff --git a/migration/ram.c b/migration/ram.c
index 60ea913..723af67 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3343,8 +3343,7 @@ int colo_init_ram_cache(void)
WITH_RCU_READ_LOCK_GUARD() {
RAMBLOCK_FOREACH_NOT_IGNORED(block) {
block->colo_cache = qemu_anon_ram_alloc(block->used_length,
- NULL,
- false);
+ NULL, false, false);
if (!block->colo_cache) {
error_report("%s: Can't alloc memory for COLO cache of block %s,"
"size 0x" RAM_ADDR_FMT, __func__, block->idstr,
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index a110aa6..11ea8e1 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -1591,6 +1591,7 @@ static void *file_ram_alloc(RAMBlock *block,
qemu_map_flags = readonly ? QEMU_MAP_READONLY : 0;
qemu_map_flags |= (block->flags & RAM_SHARED) ? QEMU_MAP_SHARED : 0;
qemu_map_flags |= (block->flags & RAM_PMEM) ? QEMU_MAP_SYNC : 0;
+ qemu_map_flags |= (block->flags & RAM_NORESERVE) ? QEMU_MAP_NORESERVE : 0;
area = qemu_ram_mmap(fd, memory, block->mr->align, qemu_map_flags, offset);
if (area == MAP_FAILED) {
error_setg_errno(errp, errno,
@@ -1716,6 +1717,11 @@ bool qemu_ram_is_shared(RAMBlock *rb)
return rb->flags & RAM_SHARED;
}
+bool qemu_ram_is_noreserve(RAMBlock *rb)
+{
+ return rb->flags & RAM_NORESERVE;
+}
+
/* Note: Only set at the start of postcopy */
bool qemu_ram_is_uf_zeroable(RAMBlock *rb)
{
@@ -1950,6 +1956,7 @@ static void dirty_memory_extend(ram_addr_t old_ram_size,
static void ram_block_add(RAMBlock *new_block, Error **errp)
{
+ const bool noreserve = qemu_ram_is_noreserve(new_block);
const bool shared = qemu_ram_is_shared(new_block);
RAMBlock *block;
RAMBlock *last_block = NULL;
@@ -1973,7 +1980,7 @@ static void ram_block_add(RAMBlock *new_block, Error **errp)
} else {
new_block->host = qemu_anon_ram_alloc(new_block->max_length,
&new_block->mr->align,
- shared);
+ shared, noreserve);
if (!new_block->host) {
error_setg_errno(errp, errno,
"cannot set up guest memory '%s'",
@@ -2045,7 +2052,7 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
int64_t file_size, file_align;
/* Just support these ram flags by now. */
- assert((ram_flags & ~(RAM_SHARED | RAM_PMEM)) == 0);
+ assert((ram_flags & ~(RAM_SHARED | RAM_PMEM | RAM_NORESERVE)) == 0);
if (xen_enabled()) {
error_setg(errp, "-mem-path not supported with Xen");
@@ -2137,6 +2144,8 @@ RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size,
Error *local_err = NULL;
assert((ram_flags & ~(RAM_SHARED | RAM_RESIZEABLE | RAM_PREALLOC)) == 0);
+ assert((ram_flags & ~(RAM_SHARED | RAM_RESIZEABLE | RAM_PREALLOC |
+ RAM_NORESERVE)) == 0);
assert(!host ^ (ram_flags & RAM_PREALLOC));
size = HOST_PAGE_ALIGN(size);
@@ -2170,7 +2179,7 @@ RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
RAMBlock *qemu_ram_alloc(ram_addr_t size, uint32_t ram_flags,
MemoryRegion *mr, Error **errp)
{
- assert((ram_flags & ~RAM_SHARED) == 0);
+ assert((ram_flags & ~(RAM_SHARED | RAM_NORESERVE)) == 0);
return qemu_ram_alloc_internal(size, size, NULL, NULL, ram_flags, mr, errp);
}
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index 1ddc0e2..d0cf4aa 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -20,6 +20,7 @@
#include "qemu/osdep.h"
#include "qemu/mmap-alloc.h"
#include "qemu/host-utils.h"
+#include "qemu/error-report.h"
#define HUGETLBFS_MAGIC 0x958458f6
@@ -121,6 +122,7 @@ static void *mmap_reserve(size_t size, int fd)
static void *mmap_activate(void *ptr, size_t size, int fd,
uint32_t qemu_map_flags, off_t map_offset)
{
+ const bool noreserve = qemu_map_flags & QEMU_MAP_NORESERVE;
const bool readonly = qemu_map_flags & QEMU_MAP_READONLY;
const bool shared = qemu_map_flags & QEMU_MAP_SHARED;
const bool sync = qemu_map_flags & QEMU_MAP_SYNC;
@@ -129,6 +131,11 @@ static void *mmap_activate(void *ptr, size_t size, int fd,
int flags = MAP_FIXED;
void *activated_ptr;
+ if (noreserve) {
+ error_report("Skipping reservation of swap space is not supported");
+ return MAP_FAILED;
+ }
+
flags |= fd == -1 ? MAP_ANONYMOUS : 0;
flags |= shared ? MAP_SHARED : MAP_PRIVATE;
if (shared && sync) {
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 0dd7784..e8bdb02 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -227,9 +227,11 @@ void *qemu_memalign(size_t alignment, size_t size)
}
/* alloc shared memory pages */
-void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared)
+void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared,
+ bool noreserve)
{
- const uint32_t qemu_map_flags = shared ? QEMU_MAP_SHARED : 0;
+ const uint32_t qemu_map_flags = (shared ? QEMU_MAP_SHARED : 0) |
+ (noreserve ? QEMU_MAP_NORESERVE : 0);
size_t align = QEMU_VMALLOC_ALIGN;
void *ptr = qemu_ram_mmap(-1, size, align, qemu_map_flags, 0);
diff --git a/util/oslib-win32.c b/util/oslib-win32.c
index ca99356..ee3a369 100644
--- a/util/oslib-win32.c
+++ b/util/oslib-win32.c
@@ -38,6 +38,7 @@
#include "trace.h"
#include "qemu/sockets.h"
#include "qemu/cutils.h"
+#include "qemu/error-report.h"
#include <malloc.h>
/* this must come after including "trace.h" */
@@ -76,10 +77,20 @@ static int get_allocation_granularity(void)
return system_info.dwAllocationGranularity;
}
-void *qemu_anon_ram_alloc(size_t size, uint64_t *align, bool shared)
+void *qemu_anon_ram_alloc(size_t size, uint64_t *align, bool shared,
+ bool noreserve)
{
void *ptr;
+ if (noreserve) {
+ /*
+ * We need a MEM_COMMIT before accessing any memory in a MEM_RESERVE
+ * area; we cannot easily mimic POSIX MAP_NORESERVE semantics.
+ */
+ error_report("Skipping reservation of swap space is not supported.");
+ return NULL;
+ }
+
ptr = VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE);
trace_qemu_anon_ram_alloc(size, ptr);
generated by cgit v1.1 at 2024-12-25 15:18:51 +0000