From afa2788662cc054a0b73a44799db575633424e93 Mon Sep 17 00:00:00 2001
From: Pavel Hrdina <phrdina@redhat.com>
Date: Mon, 24 Jun 2019 14:30:59 +0200
Subject: [PATCH] vircgroup: introduce virCgroupV2DevicesCreateProg
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This function creates new BPF program with new empty BPF map with the
default size and attaches it to the guest cgroup.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
---
 src/libvirt_private.syms      |  1 +
 src/util/vircgroupv2devices.c | 50 +++++++++++++++++++++++++++++++++++
 src/util/vircgroupv2devices.h |  3 +++
 3 files changed, 54 insertions(+)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index d4e446cbef..b75956c4e1 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1719,6 +1719,7 @@ virCgroupV2Register;
 # util/vircgroupv2devices.h
 virCgroupV2DevicesAttachProg;
 virCgroupV2DevicesAvailable;
+virCgroupV2DevicesCreateProg;
 virCgroupV2DevicesDetectProg;
 
 # util/virclosecallbacks.h
diff --git a/src/util/vircgroupv2devices.c b/src/util/vircgroupv2devices.c
index 62f66250c3..330e40c63a 100644
--- a/src/util/vircgroupv2devices.c
+++ b/src/util/vircgroupv2devices.c
@@ -426,6 +426,46 @@ virCgroupV2DevicesDetectProg(virCgroupPtr group)
 
     return 0;
 }
+
+
+# define VIR_CGROUP_V2_INITIAL_BPF_MAP_SIZE 64
+
+static int
+virCgroupV2DevicesCreateMap(size_t size)
+{
+    int mapfd = virBPFCreateMap(BPF_MAP_TYPE_HASH, sizeof(uint64_t),
+                                sizeof(uint32_t), size);
+
+    if (mapfd < 0) {
+        virReportSystemError(errno, "%s",
+                             _("failed to initialize device BPF map"));
+        return -1;
+    }
+
+    return mapfd;
+}
+
+
+int
+virCgroupV2DevicesCreateProg(virCgroupPtr group)
+{
+    VIR_AUTOCLOSE mapfd = -1;
+
+    if (group->unified.devices.progfd > 0 && group->unified.devices.mapfd > 0)
+        return 0;
+
+    mapfd = virCgroupV2DevicesCreateMap(VIR_CGROUP_V2_INITIAL_BPF_MAP_SIZE);
+    if (mapfd < 0)
+        return -1;
+
+    if (virCgroupV2DevicesAttachProg(group, mapfd,
+                                     VIR_CGROUP_V2_INITIAL_BPF_MAP_SIZE) < 0) {
+        return -1;
+    }
+
+    mapfd = -1;
+    return 0;
+}
 #else /* !HAVE_DECL_BPF_CGROUP_DEVICE */
 bool
 virCgroupV2DevicesAvailable(virCgroupPtr group G_GNUC_UNUSED)
@@ -454,4 +494,14 @@ virCgroupV2DevicesDetectProg(virCgroupPtr group G_GNUC_UNUSED)
                            "with this kernel"));
     return -1;
 }
+
+
+int
+virCgroupV2DevicesCreateProg(virCgroupPtr group G_GNUC_UNUSED)
+{
+    virReportSystemError(ENOSYS, "%s",
+                         _("cgroups v2 BPF devices not supported "
+                           "with this kernel"));
+    return -1;
+}
 #endif /* !HAVE_DECL_BPF_CGROUP_DEVICE */
diff --git a/src/util/vircgroupv2devices.h b/src/util/vircgroupv2devices.h
index 882bbd66f1..db1316d072 100644
--- a/src/util/vircgroupv2devices.h
+++ b/src/util/vircgroupv2devices.h
@@ -30,3 +30,6 @@ virCgroupV2DevicesAttachProg(virCgroupPtr group,
 
 int
 virCgroupV2DevicesDetectProg(virCgroupPtr group);
+
+int
+virCgroupV2DevicesCreateProg(virCgroupPtr group);
-- 
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