1 files changed, 51 insertions, 6 deletions

diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index ddf469fe09..110436d088 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -40,6 +40,7 @@
 #include "trace.h"
 #include "exec/gdbstub.h"
 #include "exec/memattrs.h"
+#include "sysemu/hostmem.h"
 
 //#define DEBUG_KVM
 
@@ -303,16 +304,11 @@ static void kvm_get_smmu_info(PowerPCCPU *cpu, struct kvm_ppc_smmu_info *info)
     kvm_get_fallback_smmu_info(cpu, info);
 }
 
-static long getrampagesize(void)
+static long gethugepagesize(const char *mem_path)
 {
     struct statfs fs;
     int ret;
 
-    if (!mem_path) {
-        /* guest RAM is backed by normal anonymous pages */
-        return getpagesize();
-    }
-
     do {
         ret = statfs(mem_path, &fs);
     } while (ret != 0 && errno == EINTR);
@@ -334,6 +330,55 @@ static long getrampagesize(void)
     return fs.f_bsize;
 }
 
+static int find_max_supported_pagesize(Object *obj, void *opaque)
+{
+    char *mem_path;
+    long *hpsize_min = opaque;
+
+    if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND)) {
+        mem_path = object_property_get_str(obj, "mem-path", NULL);
+        if (mem_path) {
+            long hpsize = gethugepagesize(mem_path);
+            if (hpsize < *hpsize_min) {
+                *hpsize_min = hpsize;
+            }
+        } else {
+            *hpsize_min = getpagesize();
+        }
+    }
+
+    return 0;
+}
+
+static long getrampagesize(void)
+{
+    long hpsize = LONG_MAX;
+    Object *memdev_root;
+
+    if (mem_path) {
+        return gethugepagesize(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) {
+        return getpagesize();
+    }
+
+    object_child_foreach(memdev_root, find_max_supported_pagesize, &hpsize);
+
+    return (hpsize == LONG_MAX) ? getpagesize() : hpsize;
+}
+
 static bool kvm_valid_page_size(uint32_t flags, long rampgsize, uint32_t shift)
 {
     if (!(flags & KVM_PPC_PAGE_SIZES_REAL)) {