qemu_ram_remap() unmaps the specified RAM pages, then re-maps these
pages again. This is used by KVM HWPoison support to clear HWPoisoned
page tables across guest rebooting, so that a new page may be
allocated later to recover the memory error.
Signed-off-by: Huang Ying <ying.huang@xxxxxxxxx>
---
cpu-all.h | 4 +++
cpu-common.h | 1
exec.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 65 insertions(+), 1 deletion(-)
--- a/cpu-all.h
+++ b/cpu-all.h
@@ -863,10 +863,14 @@ target_phys_addr_t cpu_get_phys_page_deb
extern int phys_ram_fd;
extern ram_addr_t ram_size;
+/* RAM is pre-allocated and passed into qemu_ram_alloc_from_ptr */
+#define RAM_PREALLOC_MASK (1 << 0)
+
typedef struct RAMBlock {
uint8_t *host;
ram_addr_t offset;
ram_addr_t length;
+ uint32_t flags;
char idstr[256];
QLIST_ENTRY(RAMBlock) next;
#if defined(__linux__) && !defined(TARGET_S390X)
--- a/exec.c
+++ b/exec.c
@@ -2837,6 +2837,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(Devic
if (host) {
new_block->host = host;
+ new_block->flags |= RAM_PREALLOC_MASK;
} else {
if (mem_path) {
#if defined (__linux__) && !defined(TARGET_S390X)
@@ -2890,7 +2891,9 @@ void qemu_ram_free(ram_addr_t addr)
QLIST_FOREACH(block, &ram_list.blocks, next) {
if (addr == block->offset) {
QLIST_REMOVE(block, next);
- if (mem_path) {
+ if (block->flags & RAM_PREALLOC_MASK) {
+ ;
+ } else if (mem_path) {
#if defined (__linux__) && !defined(TARGET_S390X)
if (block->fd) {
munmap(block->host, block->length);
@@ -2913,6 +2916,62 @@ void qemu_ram_free(ram_addr_t addr)
}
+void qemu_ram_remap(ram_addr_t addr, ram_addr_t length)
+{
+ RAMBlock *block;
+ ram_addr_t offset;
+ int flags;
+ void *area, *vaddr;
+
+ QLIST_FOREACH(block, &ram_list.blocks, next) {
+ offset = addr - block->offset;
+ if (offset < block->length) {
+ vaddr = block->host + offset;
+ if (block->flags & RAM_PREALLOC_MASK) {
+ ;
+ } else {
+ flags = MAP_FIXED;
+ munmap(vaddr, length);
+ if (mem_path) {
+#if defined (__linux__) && !defined(TARGET_S390X)
+ if (block->fd) {
+#ifdef MAP_POPULATE
+ flags |= mem_prealloc ? MAP_POPULATE | MAP_SHARED :
+ MAP_PRIVATE;
+#else
+ flags |= MAP_PRIVATE;
+#endif
+ area = mmap(vaddr, length, PROT_READ | PROT_WRITE,
+ flags, block->fd, offset);
+ } else {
+ flags |= MAP_PRIVATE | MAP_ANONYMOUS;
+ area = mmap(vaddr, length, PROT_READ | PROT_WRITE,
+ flags, -1, 0);
+ }
+#endif
+ } else {
+#if defined(TARGET_S390X) && defined(CONFIG_KVM)
+ flags |= MAP_SHARED | MAP_ANONYMOUS;
+ area = mmap(vaddr, length, PROT_EXEC|PROT_READ|PROT_WRITE,
+ flags, -1, 0);
+#else
+ flags |= MAP_PRIVATE | MAP_ANONYMOUS;
+ area = mmap(vaddr, length, PROT_READ | PROT_WRITE,
+ flags, -1, 0);
+#endif
+ }
+ if (area != vaddr) {
+ fprintf(stderr, "Could not remap addr: %lx@%lx\n",
+ length, addr);
+ exit(1);
+ }
+ qemu_madvise(vaddr, length, QEMU_MADV_MERGEABLE);
+ }
+ return;
+ }
+ }
+}
+
/* Return a host pointer to ram allocated with qemu_ram_alloc.
With the exception of the softmmu code in this file, this should
only be used for local memory (e.g. video ram) that the device owns,
--- a/cpu-common.h
+++ b/cpu-common.h
@@ -50,6 +50,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(Devic
ram_addr_t size, void *host);
ram_addr_t qemu_ram_alloc(DeviceState *dev, const char *name, ram_addr_t size);
void qemu_ram_free(ram_addr_t addr);
+void qemu_ram_remap(ram_addr_t addr, ram_addr_t length);
/* This should only be used for ram local to a device. */
void *qemu_get_ram_ptr(ram_addr_t addr);
/* Same but slower, to use for migration, where the order of
--
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