From f745b9ae2d12df0c0f2253c295f3d411a8a4165d Mon Sep 17 00:00:00 2001
Message-Id: <f745b9ae2d12df0c0f2253c295f3d411a8a4165d@dist-git>
From: Michal Privoznik <mprivozn@redhat.com>
Date: Mon, 5 Sep 2022 10:34:44 +0200
Subject: [PATCH] qemu_process: Don't require a hugetlbfs mount for memfd

The aim of qemuProcessNeedHugepagesPath() is to determine whether
a hugetlbfs mount point is required for given domain (as in
whether qemuBuildMemoryBackendProps() picks up
memory-backend-file pointing to a hugetlbfs mount point). Well,
when domain is configured to use memfd backend then that
condition can never be true. Therefore, skip creating domain's
private path under hugetlbfs mount points.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
(cherry picked from commit f14f8dff9330ed51d817f190a2ee9ac76dfac00b)
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2123196
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/qemu/qemu_process.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 5c6657a876..540eee9ff0 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -3810,8 +3810,18 @@ qemuProcessNeedHugepagesPath(virDomainDef *def,
     const long system_pagesize = virGetSystemPageSizeKB();
     size_t i;
 
-    if (def->mem.source == VIR_DOMAIN_MEMORY_SOURCE_FILE)
+    switch ((virDomainMemorySource)def->mem.source) {
+    case VIR_DOMAIN_MEMORY_SOURCE_FILE:
+        /* This needs a hugetlbfs mount. */
         return true;
+    case VIR_DOMAIN_MEMORY_SOURCE_MEMFD:
+        /* memfd works without a hugetlbfs mount */
+        return false;
+    case VIR_DOMAIN_MEMORY_SOURCE_NONE:
+    case VIR_DOMAIN_MEMORY_SOURCE_ANONYMOUS:
+    case VIR_DOMAIN_MEMORY_SOURCE_LAST:
+        break;
+    }
 
     for (i = 0; i < def->mem.nhugepages; i++) {
         if (def->mem.hugepages[i].size != system_pagesize)
-- 
2.38.0