[PATCH v3 5/5] qemu_domain.c: align all pSeries mem modules when PARSE_ABI_UPDATE

Daniel Henrique Barboza danielhb413 at gmail.com
Fri Dec 4 01:05:29 UTC 2020


qemuDomainAlignMemorySizes() has an operation order problem. We are
calculating 'initialmem' without aligning the memory modules first.
Since we're aligning the dimms afterwards this can create inconsistencies
in the end result. x86 has alignment of 1-2MiB and it's not severely
impacted by it, but pSeries works with 256MiB alignment and the difference
is noticeable.

This is the case of the existing 'memory-hotplug-ppc64-nonuma' test.
The test consists of a 2GiB (aligned value) guest with 2 ~520MiB dimms,
both unaligned. 'initialmem' is calculated by taking total_mem and
subtracting the dimms size (via virDomainDefGetMemoryInitial()), which
wil give us 2GiB - 520MiB - 520MiB, ending up with a little more than
an 1GiB of 'initialmem'. Note that this value is now unaligned, and
will be aligned up via VIR_ROUND_UP(), and we'll end up with 'initialmem'
of 1GiB + 256MiB. Given that the dimms are aligned later on, the end
result for QEMU is that the guest will have a 'mem' size of 1310720k,
plus the two 512 MiB dimms, exceeding in 256MiB the desired 2GiB
memory and currentMemory specified in the XML.

Existing guests can't be fixed without breaking ABI, but we have
code already in place to align pSeries NVDIMM modules for new guests.
Let's extend it to align all pSeries mem modules.

A new test, 'memory-hotplug-ppc64-nonuma-abi-update', a copy of the
existing 'memory-hotplug-ppc64-nonuma', was added to demonstrate the
result for new pSeries guests. For the same unaligned XML mentioned
above, after applying this patch:

- starting QEMU mem size without PARSE_ABI_UPDATE:
    -m size=1310720k,slots=16,maxmem=4194304k \ (no changes)

- starting QEMU mem size with PARSE_ABI_UPDATE:
    -m size=1048576k,slots=16,maxmem=4194304k \ (size fixed)

Reviewed-by: Michal Privoznik <mprivozn at redhat.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413 at gmail.com>
---
 src/qemu/qemu_domain.c                        | 14 +++++--
 ...emory-hotplug-ppc64-nonuma-abi-update.args | 29 ++++++++++++++
 ...memory-hotplug-ppc64-nonuma-abi-update.xml |  1 +
 tests/qemuxml2argvtest.c                      |  7 ++++
 ...memory-hotplug-ppc64-nonuma-abi-update.xml | 38 +++++++++++++++++++
 tests/qemuxml2xmltest.c                       |  7 ++++
 6 files changed, 92 insertions(+), 4 deletions(-)
 create mode 100644 tests/qemuxml2argvdata/memory-hotplug-ppc64-nonuma-abi-update.args
 create mode 120000 tests/qemuxml2argvdata/memory-hotplug-ppc64-nonuma-abi-update.xml
 create mode 100644 tests/qemuxml2xmloutdata/memory-hotplug-ppc64-nonuma-abi-update.xml

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 5fff7d312d..e7f82d42ed 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -5395,10 +5395,16 @@ qemuDomainMemoryDefPostParse(virDomainMemoryDefPtr mem, virArch arch,
      * later on by qemuDomainAlignMemorySizes() to contemplate existing
      * guests as well. */
     if (parseFlags & VIR_DOMAIN_DEF_PARSE_ABI_UPDATE) {
-        if (ARCH_IS_PPC64(arch) &&
-            mem->model == VIR_DOMAIN_MEMORY_MODEL_NVDIMM &&
-            qemuDomainNVDimmAlignSizePseries(mem) < 0)
-            return -1;
+        if (ARCH_IS_PPC64(arch)) {
+            unsigned long long ppc64MemModuleAlign = 256 * 1024;
+
+            if (mem->model == VIR_DOMAIN_MEMORY_MODEL_NVDIMM) {
+                if (qemuDomainNVDimmAlignSizePseries(mem) < 0)
+                    return -1;
+            } else {
+                mem->size = VIR_ROUND_UP(mem->size, ppc64MemModuleAlign);
+            }
+        }
     }
 
     return 0;
diff --git a/tests/qemuxml2argvdata/memory-hotplug-ppc64-nonuma-abi-update.args b/tests/qemuxml2argvdata/memory-hotplug-ppc64-nonuma-abi-update.args
new file mode 100644
index 0000000000..ac741b80c0
--- /dev/null
+++ b/tests/qemuxml2argvdata/memory-hotplug-ppc64-nonuma-abi-update.args
@@ -0,0 +1,29 @@
+LC_ALL=C \
+PATH=/bin \
+HOME=/tmp/lib/domain--1-QEMUGuest1 \
+USER=test \
+LOGNAME=test \
+XDG_DATA_HOME=/tmp/lib/domain--1-QEMUGuest1/.local/share \
+XDG_CACHE_HOME=/tmp/lib/domain--1-QEMUGuest1/.cache \
+XDG_CONFIG_HOME=/tmp/lib/domain--1-QEMUGuest1/.config \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu-system-ppc64 \
+-name QEMUGuest1 \
+-S \
+-machine pseries,accel=kvm,usb=off,dump-guest-core=off \
+-m size=1048576k,slots=16,maxmem=4194304k \
+-realtime mlock=off \
+-smp 1,sockets=1,cores=1,threads=1 \
+-object memory-backend-ram,id=memdimm0,size=536870912 \
+-device pc-dimm,memdev=memdimm0,id=dimm0,slot=0 \
+-object memory-backend-ram,id=memdimm1,size=536870912 \
+-device pc-dimm,memdev=memdimm1,id=dimm1,slot=1 \
+-uuid 49545eb3-75e1-2d0a-acdd-f0294406c99e \
+-display none \
+-no-user-config \
+-nodefaults \
+-chardev socket,id=charmonitor,path=/tmp/lib/domain--1-QEMUGuest1/monitor.sock,\
+server,nowait \
+-mon chardev=charmonitor,id=monitor,mode=control \
+-rtc base=utc \
+-no-shutdown
diff --git a/tests/qemuxml2argvdata/memory-hotplug-ppc64-nonuma-abi-update.xml b/tests/qemuxml2argvdata/memory-hotplug-ppc64-nonuma-abi-update.xml
new file mode 120000
index 0000000000..03410026cc
--- /dev/null
+++ b/tests/qemuxml2argvdata/memory-hotplug-ppc64-nonuma-abi-update.xml
@@ -0,0 +1 @@
+memory-hotplug-ppc64-nonuma.xml
\ No newline at end of file
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index a9bd210ca3..7c9dc0e641 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -3005,6 +3005,13 @@ mymain(void)
     DO_TEST("memory-hotplug-ppc64-nonuma", QEMU_CAPS_KVM, QEMU_CAPS_DEVICE_PC_DIMM, QEMU_CAPS_NUMA,
             QEMU_CAPS_DEVICE_SPAPR_PCI_HOST_BRIDGE,
             QEMU_CAPS_OBJECT_MEMORY_RAM, QEMU_CAPS_OBJECT_MEMORY_FILE);
+    DO_TEST_FULL("memory-hotplug-ppc64-nonuma-abi-update",
+                 ARG_PARSEFLAGS, VIR_DOMAIN_DEF_PARSE_ABI_UPDATE,
+                 ARG_QEMU_CAPS,
+                 QEMU_CAPS_KVM, QEMU_CAPS_DEVICE_PC_DIMM,
+                 QEMU_CAPS_NUMA, QEMU_CAPS_DEVICE_SPAPR_PCI_HOST_BRIDGE,
+                 QEMU_CAPS_OBJECT_MEMORY_RAM,
+                 QEMU_CAPS_OBJECT_MEMORY_FILE);
     DO_TEST_CAPS_LATEST("memory-hotplug-nvdimm");
     DO_TEST_CAPS_LATEST("memory-hotplug-nvdimm-access");
     DO_TEST_CAPS_LATEST("memory-hotplug-nvdimm-label");
diff --git a/tests/qemuxml2xmloutdata/memory-hotplug-ppc64-nonuma-abi-update.xml b/tests/qemuxml2xmloutdata/memory-hotplug-ppc64-nonuma-abi-update.xml
new file mode 100644
index 0000000000..4edb786e6f
--- /dev/null
+++ b/tests/qemuxml2xmloutdata/memory-hotplug-ppc64-nonuma-abi-update.xml
@@ -0,0 +1,38 @@
+<domain type='kvm'>
+  <name>QEMUGuest1</name>
+  <uuid>49545eb3-75e1-2d0a-acdd-f0294406c99e</uuid>
+  <maxMemory slots='16' unit='KiB'>4194304</maxMemory>
+  <memory unit='KiB'>2097152</memory>
+  <currentMemory unit='KiB'>2097152</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='ppc64' machine='pseries'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-ppc64</emulator>
+    <controller type='usb' index='0' model='none'/>
+    <controller type='pci' index='0' model='pci-root'>
+      <model name='spapr-pci-host-bridge'/>
+      <target index='0'/>
+    </controller>
+    <memballoon model='none'/>
+    <panic model='pseries'/>
+    <memory model='dimm'>
+      <target>
+        <size unit='KiB'>524288</size>
+      </target>
+      <address type='dimm' slot='0'/>
+    </memory>
+    <memory model='dimm'>
+      <target>
+        <size unit='KiB'>524288</size>
+      </target>
+      <address type='dimm' slot='1'/>
+    </memory>
+  </devices>
+</domain>
diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c
index 18faea2b33..1968be6782 100644
--- a/tests/qemuxml2xmltest.c
+++ b/tests/qemuxml2xmltest.c
@@ -1232,6 +1232,13 @@ mymain(void)
     DO_TEST("memory-hotplug-ppc64-nonuma", QEMU_CAPS_KVM, QEMU_CAPS_DEVICE_PC_DIMM, QEMU_CAPS_NUMA,
             QEMU_CAPS_DEVICE_SPAPR_PCI_HOST_BRIDGE,
             QEMU_CAPS_OBJECT_MEMORY_RAM, QEMU_CAPS_OBJECT_MEMORY_FILE);
+    DO_TEST_FULL("memory-hotplug-ppc64-nonuma-abi-update", WHEN_BOTH,
+                 ARG_PARSEFLAGS, VIR_DOMAIN_DEF_PARSE_ABI_UPDATE,
+                 ARG_QEMU_CAPS,
+                 QEMU_CAPS_KVM, QEMU_CAPS_DEVICE_PC_DIMM,
+                 QEMU_CAPS_NUMA, QEMU_CAPS_DEVICE_SPAPR_PCI_HOST_BRIDGE,
+                 QEMU_CAPS_OBJECT_MEMORY_RAM,
+                 QEMU_CAPS_OBJECT_MEMORY_FILE, QEMU_CAPS_LAST);
     DO_TEST("memory-hotplug", NONE);
     DO_TEST("memory-hotplug-dimm", QEMU_CAPS_DEVICE_PC_DIMM);
     DO_TEST("memory-hotplug-nvdimm", QEMU_CAPS_DEVICE_NVDIMM);
-- 
2.26.2




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