1 files changed, 26 insertions, 8 deletions
diff --git a/target/i386/hax-mem.c b/target/i386/hax-mem.c
index 27a0d214f2..f46e85544d 100644
--- a/target/i386/hax-mem.c
+++ b/target/i386/hax-mem.c
@@ -174,6 +174,7 @@ static void hax_process_section(MemoryRegionSection *section, uint8_t flags)
     ram_addr_t size = int128_get64(section->size);
     unsigned int delta;
     uint64_t host_va;
+    uint32_t max_mapping_size;
 
     /* We only care about RAM and ROM regions */
     if (!memory_region_is_ram(mr)) {
@@ -206,10 +207,23 @@ static void hax_process_section(MemoryRegionSection *section, uint8_t flags)
         flags |= HAX_RAM_INFO_ROM;
     }
 
-    /* the kernel module interface uses 32-bit sizes (but we could split...) */
-    g_assert(size <= UINT32_MAX);
-
-    hax_update_mapping(start_pa, size, host_va, flags);
+    /*
+     * The kernel module interface uses 32-bit sizes:
+     * https://github.com/intel/haxm/blob/master/API.md#hax_vm_ioctl_set_ram
+     *
+     * If the mapping size is longer than 32 bits, we can't process it in one
+     * call into the kernel. Instead, we split the mapping into smaller ones,
+     * and call hax_update_mapping() on each.
+     */
+    max_mapping_size = UINT32_MAX & qemu_real_host_page_mask;
+    while (size > max_mapping_size) {
+        hax_update_mapping(start_pa, max_mapping_size, host_va, flags);
+        start_pa += max_mapping_size;
+        size -= max_mapping_size;
+        host_va += max_mapping_size;
+    }
+    /* Now size <= max_mapping_size */
+    hax_update_mapping(start_pa, (uint32_t)size, host_va, flags);
 }
 
 static void hax_region_add(MemoryListener *listener,
@@ -283,12 +297,16 @@ static MemoryListener hax_memory_listener = {
 static void hax_ram_block_added(RAMBlockNotifier *n, void *host, size_t size)
 {
     /*
-     * In HAX, QEMU allocates the virtual address, and HAX kernel
-     * populates the memory with physical memory. Currently we have no
-     * paging, so user should make sure enough free memory in advance.
+     * We must register each RAM block with the HAXM kernel module, or
+     * hax_set_ram() will fail for any mapping into the RAM block:
+     * https://github.com/intel/haxm/blob/master/API.md#hax_vm_ioctl_alloc_ram
+     *
+     * Old versions of the HAXM kernel module (< 6.2.0) used to preallocate all
+     * host physical pages for the RAM block as part of this registration
+     * process, hence the name hax_populate_ram().
      */
     if (hax_populate_ram((uint64_t)(uintptr_t)host, size) < 0) {
-        fprintf(stderr, "HAX failed to populate RAM");
+        fprintf(stderr, "HAX failed to populate RAM\n");
         abort();
     }
 }