From 12f6ee75efb15263f62fb12c693b74b116ac4a4f Mon Sep 17 00:00:00 2001

Message-Id: <12f6ee75efb15263f62fb12c693b74b116ac4a4f@dist-git>

From: Michal Privoznik <mprivozn@redhat.com>

Date: Thu, 9 Nov 2017 16:06:47 +0100

Subject: [PATCH] qemu: Use predictable file names for memory-backend-file

https://bugzilla.redhat.com/show_bug.cgi?id=1461214

In some cases management application needs to allocate memory for

qemu upfront and then just let qemu use that. Since we don't want

to expose path for memory-backend-file anywhere in the domain

XML, we can generate predictable paths. In this case:

  $memoryBackingDir/libvirt/qemu/$shortName/$alias

where $shortName is result of virDomainDefGetShortName().

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

Reviewed-by: John Ferlan <jferlan@redhat.com>

(cherry picked from commit fec8f9c49afb479f6c3c8c388426945f2c1f099b)

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

---

 src/qemu/qemu_command.c                            |  2 +-

 src/qemu/qemu_conf.c                               | 55 +++++++++++++++++-

 src/qemu/qemu_conf.h                               |  9 ++-

 src/qemu/qemu_driver.c                             | 17 ++++++

 src/qemu/qemu_process.c                            | 65 ++++++++++++++++++----

 .../qemuxml2argv-cpu-numa-memshared.args           |  6 +-

 .../qemuxml2argv-fd-memory-numa-topology.args      |  3 +-

 .../qemuxml2argv-fd-memory-numa-topology2.args     |  6 +-

 .../qemuxml2argv-fd-memory-numa-topology3.args     |  9 ++-

 .../qemuxml2argv-hugepages-memaccess2.args         |  9 ++-

 10 files changed, 155 insertions(+), 26 deletions(-)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c

index 57c855c047..f8eb59884c 100644

--- a/src/qemu/qemu_command.c

+++ b/src/qemu/qemu_command.c

@@ -3439,7 +3439,7 @@ qemuBuildMemoryBackendStr(virJSONValuePtr *backendProps,

         } else {

             /* We can have both pagesize and mem source. If that's the case,

              * prefer hugepages as those are more specific. */

-            if (qemuGetMemoryBackingPath(cfg, &memPath) < 0)

+            if (qemuGetMemoryBackingPath(def, cfg, mem->info.alias, &memPath) < 0)

                 goto cleanup;

         }

diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c

index 3b670a68c5..e04523223d 100644

--- a/src/qemu/qemu_conf.c

+++ b/src/qemu/qemu_conf.c

@@ -1767,9 +1767,41 @@ qemuGetDomainHupageMemPath(const virDomainDef *def,

 }

+int

+qemuGetMemoryBackingBasePath(virQEMUDriverConfigPtr cfg,

+                             char **path)

+{

+    return virAsprintf(path, "%s/libvirt/qemu", cfg->memoryBackingDir);

+}

+

+

+int

+qemuGetMemoryBackingDomainPath(const virDomainDef *def,

+                               virQEMUDriverConfigPtr cfg,

+                               char **path)

+{

+    char *shortName = NULL;

+    char *base = NULL;

+    int ret = -1;

+

+    if (!(shortName = virDomainDefGetShortName(def)) ||

+        qemuGetMemoryBackingBasePath(cfg, &base) < 0 ||

+        virAsprintf(path, "%s/%s", base, shortName) < 0)

+        goto cleanup;

+

+    ret = 0;

+ cleanup:

+    VIR_FREE(base);

+    VIR_FREE(shortName);

+    return ret;

+}

+

+

 /**

  * qemuGetMemoryBackingPath:

+ * @def: domain definition

  * @cfg: the driver config

+ * @alias: memory object alias

  * @memPath: constructed path

  *

  * Constructs path to memory backing dir and stores it at @memPath.

@@ -1778,8 +1810,27 @@ qemuGetDomainHupageMemPath(const virDomainDef *def,

  *          -1 otherwise (with error reported).

  */

 int

-qemuGetMemoryBackingPath(virQEMUDriverConfigPtr cfg,

+qemuGetMemoryBackingPath(const virDomainDef *def,

+                         virQEMUDriverConfigPtr cfg,

+                         const char *alias,

                          char **memPath)

 {

-    return VIR_STRDUP(*memPath, cfg->memoryBackingDir);

+    char *domainPath = NULL;

+    int ret = -1;

+

+    if (!alias) {

+        /* This should never happen (TM) */

+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",

+                       _("memory device alias is not assigned"));

+        goto cleanup;

+    }

+

+    if (qemuGetMemoryBackingDomainPath(def, cfg, &domainPath) < 0 ||

+        virAsprintf(memPath, "%s/%s", domainPath, alias) < 0)

+        goto cleanup;

+

+    ret = 0;

+ cleanup:

+    VIR_FREE(domainPath);

+    return ret;

 }

diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h

index 9d6866816f..a553e30e2e 100644

--- a/src/qemu/qemu_conf.h

+++ b/src/qemu/qemu_conf.h

@@ -364,6 +364,13 @@ int qemuGetDomainHupageMemPath(const virDomainDef *def,

                                unsigned long long pagesize,

                                char **memPath);

-int qemuGetMemoryBackingPath(virQEMUDriverConfigPtr cfg,

+int qemuGetMemoryBackingBasePath(virQEMUDriverConfigPtr cfg,

+                                 char **path);

+int qemuGetMemoryBackingDomainPath(const virDomainDef *def,

+                                   virQEMUDriverConfigPtr cfg,

+                                   char **path);

+int qemuGetMemoryBackingPath(const virDomainDef *def,

+                             virQEMUDriverConfigPtr cfg,

+                             const char *alias,

                              char **memPath);

 #endif /* __QEMUD_CONF_H */

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c

index 5617c78997..6096e00b2a 100644

--- a/src/qemu/qemu_driver.c

+++ b/src/qemu/qemu_driver.c

@@ -631,6 +631,7 @@ qemuStateInitialize(bool privileged,

     uid_t run_uid = -1;

     gid_t run_gid = -1;

     char *hugepagePath = NULL;

+    char *memoryBackingPath = NULL;

     size_t i;

     if (VIR_ALLOC(qemu_driver) < 0)

@@ -889,6 +890,21 @@ qemuStateInitialize(bool privileged,

         VIR_FREE(hugepagePath);

     }

+    if (qemuGetMemoryBackingBasePath(cfg, &memoryBackingPath) < 0)

+        goto error;

+

+    if (virFileMakePath(memoryBackingPath) < 0) {

+        virReportSystemError(errno,

+                             _("unable to create memory backing path %s"),

+                             memoryBackingPath);

+        goto error;

+    }

+

+    if (privileged &&

+        virFileUpdatePerm(memoryBackingPath,

+                          0, S_IXGRP | S_IXOTH) < 0)

+        goto error;

+

     if (!(qemu_driver->closeCallbacks = virCloseCallbacksNew()))

         goto error;

@@ -946,6 +962,7 @@ qemuStateInitialize(bool privileged,

     virObjectUnref(conn);

     VIR_FREE(driverConf);

     VIR_FREE(hugepagePath);

+    VIR_FREE(memoryBackingPath);

     qemuStateCleanup();

     return -1;

 }

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c

index 3324cc61f1..86a4dee88e 100644

--- a/src/qemu/qemu_process.c

+++ b/src/qemu/qemu_process.c

@@ -3324,6 +3324,36 @@ qemuProcessNeedHugepagesPath(virDomainDefPtr def,

 }

+static bool

+qemuProcessNeedMemoryBackingPath(virDomainDefPtr def,

+                                 virDomainMemoryDefPtr mem)

+{

+    size_t i;

+    size_t numaNodes;

+

+    if (def->mem.source == VIR_DOMAIN_MEMORY_SOURCE_FILE ||

+        def->mem.access != VIR_DOMAIN_MEMORY_ACCESS_DEFAULT)

+        return true;

+

+    numaNodes = virDomainNumaGetNodeCount(def->numa);

+    for (i = 0; i < numaNodes; i++) {

+        if (virDomainNumaGetNodeMemoryAccessMode(def->numa, i)

+            != VIR_DOMAIN_MEMORY_ACCESS_DEFAULT)

+            return true;

+    }

+

+    if (mem &&

+        mem->model == VIR_DOMAIN_MEMORY_MODEL_DIMM &&

+        (mem->access != VIR_DOMAIN_MEMORY_ACCESS_DEFAULT ||

+         (mem->targetNode >= 0 &&

+          virDomainNumaGetNodeMemoryAccessMode(def->numa, mem->targetNode)

+          != VIR_DOMAIN_MEMORY_ACCESS_DEFAULT)))

+        return true;

+

+    return false;

+}

+

+

 static int

 qemuProcessBuildDestroyMemoryPathsImpl(virQEMUDriverPtr driver,

                                        virDomainDefPtr def,

@@ -3363,33 +3393,46 @@ qemuProcessBuildDestroyMemoryPaths(virQEMUDriverPtr driver,

                                    bool build)

 {

     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);

-    char *hugepagePath = NULL;

+    char *path = NULL;

     size_t i;

-    bool shouldBuild = false;

+    bool shouldBuildHP = false;

+    bool shouldBuildMB = false;

     int ret = -1;

-    if (build)

-        shouldBuild = qemuProcessNeedHugepagesPath(vm->def, mem);

+    if (build) {

+        shouldBuildHP = qemuProcessNeedHugepagesPath(vm->def, mem);

+        shouldBuildMB = qemuProcessNeedMemoryBackingPath(vm->def, mem);

+    }

-    if (!build || shouldBuild) {

+    if (!build || shouldBuildHP) {

         for (i = 0; i < cfg->nhugetlbfs; i++) {

-            VIR_FREE(hugepagePath);

-            hugepagePath = qemuGetDomainHugepagePath(vm->def, &cfg->hugetlbfs[i]);

+            path = qemuGetDomainHugepagePath(vm->def, &cfg->hugetlbfs[i]);

-            if (!hugepagePath)

+            if (!path)

                 goto cleanup;

             if (qemuProcessBuildDestroyMemoryPathsImpl(driver, vm->def,

-                                                       hugepagePath, build) < 0)

+                                                       path, build) < 0)

                 goto cleanup;

-            VIR_FREE(hugepagePath);

+            VIR_FREE(path);

         }

     }

+    if (!build || shouldBuildMB) {

+        if (qemuGetMemoryBackingDomainPath(vm->def, cfg, &path) < 0)

+            goto cleanup;

+

+        if (qemuProcessBuildDestroyMemoryPathsImpl(driver, vm->def,

+                                                   path, build) < 0)

+            goto cleanup;

+

+        VIR_FREE(path);

+    }

+

     ret = 0;

  cleanup:

-    VIR_FREE(hugepagePath);

+    VIR_FREE(path);

     virObjectUnref(cfg);

     return ret;

 }

diff --git a/tests/qemuxml2argvdata/qemuxml2argv-cpu-numa-memshared.args b/tests/qemuxml2argvdata/qemuxml2argv-cpu-numa-memshared.args

index 5700c3413f..3528194293 100644

--- a/tests/qemuxml2argvdata/qemuxml2argv-cpu-numa-memshared.args

+++ b/tests/qemuxml2argvdata/qemuxml2argv-cpu-numa-memshared.args

@@ -10,10 +10,12 @@ QEMU_AUDIO_DRV=none \

 -M pc \

 -m 214 \

 -smp 16,sockets=2,cores=4,threads=2 \

--object memory-backend-file,id=ram-node0,mem-path=/var/lib/libvirt/qemu/ram,\

+-object memory-backend-file,id=ram-node0,\

+mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-QEMUGuest1/ram-node0,\

 share=yes,size=112197632 \

 -numa node,nodeid=0,cpus=0-7,memdev=ram-node0 \

--object memory-backend-file,id=ram-node1,mem-path=/var/lib/libvirt/qemu/ram,\

+-object memory-backend-file,id=ram-node1,\

+mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-QEMUGuest1/ram-node1,\

 share=no,size=112197632 \

 -numa node,nodeid=1,cpus=8-15,memdev=ram-node1 \

 -uuid c7a5fdbd-edaf-9455-926a-d65c16db1809 \

diff --git a/tests/qemuxml2argvdata/qemuxml2argv-fd-memory-numa-topology.args b/tests/qemuxml2argvdata/qemuxml2argv-fd-memory-numa-topology.args

index 12f3d8ab8c..fa13532596 100644

--- a/tests/qemuxml2argvdata/qemuxml2argv-fd-memory-numa-topology.args

+++ b/tests/qemuxml2argvdata/qemuxml2argv-fd-memory-numa-topology.args

@@ -11,7 +11,8 @@ QEMU_AUDIO_DRV=none \

 -m 14336 \

 -mem-prealloc \

 -smp 8,sockets=1,cores=8,threads=1 \

--object memory-backend-file,id=ram-node0,mem-path=/var/lib/libvirt/qemu/ram,\

+-object memory-backend-file,id=ram-node0,\

+mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-instance-00000092/ram-node0,\

 share=yes,size=15032385536 \

 -numa node,nodeid=0,cpus=0-7,memdev=ram-node0 \

 -uuid 126f2720-6f8e-45ab-a886-ec9277079a67 \

diff --git a/tests/qemuxml2argvdata/qemuxml2argv-fd-memory-numa-topology2.args b/tests/qemuxml2argvdata/qemuxml2argv-fd-memory-numa-topology2.args

index 585e4d5061..6f73a1b99b 100644

--- a/tests/qemuxml2argvdata/qemuxml2argv-fd-memory-numa-topology2.args

+++ b/tests/qemuxml2argvdata/qemuxml2argv-fd-memory-numa-topology2.args

@@ -11,10 +11,12 @@ QEMU_AUDIO_DRV=none \

 -m 28672 \

 -mem-prealloc \

 -smp 20,sockets=1,cores=8,threads=1 \

--object memory-backend-file,id=ram-node0,mem-path=/var/lib/libvirt/qemu/ram,\

+-object memory-backend-file,id=ram-node0,\

+mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-instance-00000092/ram-node0,\

 share=no,size=15032385536 \

 -numa node,nodeid=0,cpus=0-7,memdev=ram-node0 \

--object memory-backend-file,id=ram-node1,mem-path=/var/lib/libvirt/qemu/ram,\

+-object memory-backend-file,id=ram-node1,\

+mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-instance-00000092/ram-node1,\

 share=yes,size=15032385536 \

 -numa node,nodeid=1,cpus=8-15,memdev=ram-node1 \

 -uuid 126f2720-6f8e-45ab-a886-ec9277079a67 \

diff --git a/tests/qemuxml2argvdata/qemuxml2argv-fd-memory-numa-topology3.args b/tests/qemuxml2argvdata/qemuxml2argv-fd-memory-numa-topology3.args

index e9a57a69e5..3c352fe035 100644

--- a/tests/qemuxml2argvdata/qemuxml2argv-fd-memory-numa-topology3.args

+++ b/tests/qemuxml2argvdata/qemuxml2argv-fd-memory-numa-topology3.args

@@ -11,13 +11,16 @@ QEMU_AUDIO_DRV=none \

 -m 43008 \

 -mem-prealloc \

 -smp 32,sockets=1,cores=24,threads=1 \

--object memory-backend-file,id=ram-node0,mem-path=/var/lib/libvirt/qemu/ram,\

+-object memory-backend-file,id=ram-node0,\

+mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-instance-00000092/ram-node0,\

 share=yes,size=15032385536 \

 -numa node,nodeid=0,cpus=0-1,memdev=ram-node0 \

--object memory-backend-file,id=ram-node1,mem-path=/var/lib/libvirt/qemu/ram,\

+-object memory-backend-file,id=ram-node1,\

+mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-instance-00000092/ram-node1,\

 share=yes,size=15032385536 \

 -numa node,nodeid=1,cpus=2-3,memdev=ram-node1 \

--object memory-backend-file,id=ram-node2,mem-path=/var/lib/libvirt/qemu/ram,\

+-object memory-backend-file,id=ram-node2,\

+mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-instance-00000092/ram-node2,\

 share=no,size=15032385536 \

 -numa node,nodeid=2,cpus=4-5,memdev=ram-node2 \

 -uuid 126f2720-6f8e-45ab-a886-ec9277079a67 \

diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hugepages-memaccess2.args b/tests/qemuxml2argvdata/qemuxml2argv-hugepages-memaccess2.args

index 55db491719..d8e506c19e 100644

--- a/tests/qemuxml2argvdata/qemuxml2argv-hugepages-memaccess2.args

+++ b/tests/qemuxml2argvdata/qemuxml2argv-hugepages-memaccess2.args

@@ -10,17 +10,20 @@ QEMU_AUDIO_DRV=none \

 -M pc \

 -m size=4194304k,slots=16,maxmem=8388608k \

 -smp 4,sockets=4,cores=1,threads=1 \

--object memory-backend-file,id=ram-node0,mem-path=/var/lib/libvirt/qemu/ram,\

+-object memory-backend-file,id=ram-node0,\

+mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-QEMUGuest1/ram-node0,\

 share=no,size=1073741824,host-nodes=0-3,policy=bind \

 -numa node,nodeid=0,cpus=0,memdev=ram-node0 \

 -object memory-backend-file,id=ram-node1,prealloc=yes,\

 mem-path=/dev/hugepages2M/libvirt/qemu/-1-QEMUGuest1,share=yes,size=1073741824,\

 host-nodes=0-3,policy=bind \

 -numa node,nodeid=1,cpus=1,memdev=ram-node1 \

--object memory-backend-file,id=ram-node2,mem-path=/var/lib/libvirt/qemu/ram,\

+-object memory-backend-file,id=ram-node2,\

+mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-QEMUGuest1/ram-node2,\

 share=no,size=1073741824,host-nodes=0-3,policy=bind \

 -numa node,nodeid=2,cpus=2,memdev=ram-node2 \

--object memory-backend-file,id=ram-node3,mem-path=/var/lib/libvirt/qemu/ram,\

+-object memory-backend-file,id=ram-node3,\

+mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-QEMUGuest1/ram-node3,\

 share=no,size=1073741824,host-nodes=3,policy=bind \

 -numa node,nodeid=3,cpus=3,memdev=ram-node3 \

 -object memory-backend-file,id=memdimm0,prealloc=yes,\

-- 

2.15.0