Merge tag 'patchew/20200219160953.13771-1-imammedo@redhat.com' of https://github.com/patchew-project/qemu into HEAD

This series removes ad hoc RAM allocation API (memory_region_allocate_system_memory)
and consolidates it around hostmem backend. It allows to

* resolve conflicts between global -mem-prealloc and hostmem's "policy" option,
  fixing premature allocation before binding policy is applied

* simplify complicated memory allocation routines which had to deal with 2 ways
  to allocate RAM.

* reuse hostmem backends of a choice for main RAM without adding extra CLI
  options to duplicate hostmem features.  A recent case was -mem-shared, to
  enable vhost-user on targets that don't support hostmem backends [1] (ex: s390)

* move RAM allocation from individual boards into generic machine code and
  provide them with prepared MemoryRegion.

* clean up deprecated NUMA features which were tied to the old API (see patches)
  - "numa: remove deprecated -mem-path fallback to anonymous RAM"
  - (POSTPONED, waiting on libvirt side) "forbid '-numa node,mem' for 5.0 and newer machine types"
  - (POSTPONED) "numa: remove deprecated implicit RAM distribution between nodes"

Introduce a new machine.memory-backend property and wrapper code that aliases
global -mem-path and -mem-alloc into automatically created hostmem backend
properties (provided memory-backend was not set explicitly given by user).
A bulk of trivial patches then follow to incrementally convert individual
boards to using machine.memory-backend provided MemoryRegion.

Board conversion typically involves:

* providing MachineClass::default_ram_size and MachineClass::default_ram_id
  so generic code could create default backend if user didn't explicitly provide
  memory-backend or -m options

* dropping memory_region_allocate_system_memory() call

* using convenience MachineState::ram MemoryRegion, which points to MemoryRegion
   allocated by ram-memdev

On top of that for some boards:

* missing ram_size checks are added (typically it were boards with fixed ram size)

* ram_size fixups are replaced by checks and hard errors, forcing user to
  provide correct "-m" values instead of ignoring it and continuing running.

After all boards are converted, the old API is removed and memory allocation
routines are cleaned up.

1 files changed, 6 insertions, 58 deletions

diff --git a/exec.c b/exec.c
index c930040f83..1276efc659 100644
--- a/exec.c
+++ b/exec.c
@@ -1668,59 +1668,18 @@ static int find_max_backend_pagesize(Object *obj, void *opaque)
 long qemu_minrampagesize(void)
 {
     long hpsize = LONG_MAX;
-    long mainrampagesize;
-    Object *memdev_root;
-    MachineState *ms = MACHINE(qdev_get_machine());
-
-    mainrampagesize = qemu_mempath_getpagesize(mem_path);
-
-    /* it's possible we have memory-backend objects with
-     * hugepage-backed RAM. these may get mapped into system
-     * address space via -numa parameters or memory hotplug
-     * hooks. we want to take these into account, but we
-     * also want to make sure these supported hugepage
-     * sizes are applicable across the entire range of memory
-     * we may boot from, so we take the min across all
-     * backends, and assume normal pages in cases where a
-     * backend isn't backed by hugepages.
-     */
-    memdev_root = object_resolve_path("/objects", NULL);
-    if (memdev_root) {
-        object_child_foreach(memdev_root, find_min_backend_pagesize, &hpsize);
-    }
-    if (hpsize == LONG_MAX) {
-        /* No additional memory regions found ==> Report main RAM page size */
-        return mainrampagesize;
-    }
-
-    /* If NUMA is disabled or the NUMA nodes are not backed with a
-     * memory-backend, then there is at least one node using "normal" RAM,
-     * so if its page size is smaller we have got to report that size instead.
-     */
-    if (hpsize > mainrampagesize &&
-        (ms->numa_state == NULL ||
-         ms->numa_state->num_nodes == 0 ||
-         ms->numa_state->nodes[0].node_memdev == NULL)) {
-        static bool warned;
-        if (!warned) {
-            error_report("Huge page support disabled (n/a for main memory).");
-            warned = true;
-        }
-        return mainrampagesize;
-    }
+    Object *memdev_root = object_resolve_path("/objects", NULL);
 
+    object_child_foreach(memdev_root, find_min_backend_pagesize, &hpsize);
     return hpsize;
 }
 
 long qemu_maxrampagesize(void)
 {
-    long pagesize = qemu_mempath_getpagesize(mem_path);
+    long pagesize = 0;
     Object *memdev_root = object_resolve_path("/objects", NULL);
 
-    if (memdev_root) {
-        object_child_foreach(memdev_root, find_max_backend_pagesize,
-                             &pagesize);
-    }
+    object_child_foreach(memdev_root, find_max_backend_pagesize, &pagesize);
     return pagesize;
 }
 #else
@@ -1843,8 +1802,6 @@ static void *file_ram_alloc(RAMBlock *block,
                             bool truncate,
                             Error **errp)
 {
-    Error *err = NULL;
-    MachineState *ms = MACHINE(qdev_get_machine());
     void *area;
 
     block->page_size = qemu_fd_getpagesize(fd);
@@ -1900,15 +1857,6 @@ static void *file_ram_alloc(RAMBlock *block,
         return NULL;
     }
 
-    if (mem_prealloc) {
-        os_mem_prealloc(fd, area, memory, ms->smp.cpus, &err);
-        if (err) {
-            error_propagate(errp, err);
-            qemu_ram_munmap(fd, area, memory);
-            return NULL;
-        }
-    }
-
     block->fd = fd;
     return area;
 }
@@ -2356,9 +2304,9 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
     size = HOST_PAGE_ALIGN(size);
     file_size = get_file_size(fd);
     if (file_size > 0 && file_size < size) {
-        error_setg(errp, "backing store %s size 0x%" PRIx64
+        error_setg(errp, "backing store size 0x%" PRIx64
                    " does not match 'size' option 0x" RAM_ADDR_FMT,
-                   mem_path, file_size, size);
+                   file_size, size);
         return NULL;
     }