[PATCH] qemu: add support for max-ram-below-4g option

Zhiyong Ye posted 1 patch 2 weeks, 4 days ago
Test syntax-check failed
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/libvirt tags/patchew/20210429125518.27917-3-yezhiyong@bytedance.com
docs/formatdomain.rst                       | 10 ++++--
docs/schemas/domaincommon.rng               |  5 +++
src/conf/domain_conf.c                      |  6 ++++
src/conf/domain_conf.h                      |  3 ++
src/conf/domain_validate.c                  | 13 ++++++++
src/qemu/qemu_command.c                     |  4 +++
tests/qemuxml2argvdata/memory-below4g.args  | 29 ++++++++++++++++
tests/qemuxml2argvdata/memory-below4g.xml   | 26 +++++++++++++++
tests/qemuxml2argvtest.c                    |  1 +
tests/qemuxml2xmloutdata/memory-below4g.xml | 37 +++++++++++++++++++++
tests/qemuxml2xmltest.c                     |  1 +
11 files changed, 133 insertions(+), 2 deletions(-)
create mode 100644 tests/qemuxml2argvdata/memory-below4g.args
create mode 100644 tests/qemuxml2argvdata/memory-below4g.xml
create mode 100644 tests/qemuxml2xmloutdata/memory-below4g.xml

[PATCH] qemu: add support for max-ram-below-4g option

Posted by Zhiyong Ye 2 weeks, 4 days ago
The 'below4g' attribute added in 'memory' element can be used to specify
the low memory area, which allows to get a larger PCI I/O window below
4G when reduce it to a smaller value, and when raise value allows legacy
non-PAE guests to have as much memory as possible in the 32bit address
space below 4G. It does not share the ``unit`` parameter with the actual
memory size and its unit defaults to "KiB".

Signed-off-by: Zhiyong Ye <yezhiyong@bytedance.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Signed-off-by: zhangruien <zhangruien@bytedance.com>
---
 docs/formatdomain.rst                       | 10 ++++--
 docs/schemas/domaincommon.rng               |  5 +++
 src/conf/domain_conf.c                      |  6 ++++
 src/conf/domain_conf.h                      |  3 ++
 src/conf/domain_validate.c                  | 13 ++++++++
 src/qemu/qemu_command.c                     |  4 +++
 tests/qemuxml2argvdata/memory-below4g.args  | 29 ++++++++++++++++
 tests/qemuxml2argvdata/memory-below4g.xml   | 26 +++++++++++++++
 tests/qemuxml2argvtest.c                    |  1 +
 tests/qemuxml2xmloutdata/memory-below4g.xml | 37 +++++++++++++++++++++
 tests/qemuxml2xmltest.c                     |  1 +
 11 files changed, 133 insertions(+), 2 deletions(-)
 create mode 100644 tests/qemuxml2argvdata/memory-below4g.args
 create mode 100644 tests/qemuxml2argvdata/memory-below4g.xml
 create mode 100644 tests/qemuxml2xmloutdata/memory-below4g.xml

diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index 1b9b221611..fd074a224e 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -940,8 +940,14 @@ Memory Allocation
    `NUMA <#elementsCPU>`__ is configured for the guest the ``memory`` element
    can be omitted. In the case of crash, optional attribute ``dumpCore`` can be
    used to control whether the guest memory should be included in the generated
-   coredump or not (values "on", "off"). ``unit`` :since:`since 0.9.11` ,
-   ``dumpCore`` :since:`since 0.10.2 (QEMU only)`
+   coredump or not (values "on", "off"). Besides, the optional ``below4g``
+   attribute can be used to specify the low memory area, which allows to get a
+   larger PCI I/O window below 4G when reduce it to a smaller value, and when
+   raise value allows legacy non-PAE guests to have as much memory as possible
+   in the 32bit address space below 4G. It does not share the ``unit`` parameter
+   with the actual memory size and its unit defaults to "KiB". ``unit`` :
+   since:`since 0.9.11` , ``dumpCore`` : since:`since 0.10.2 (QEMU only)`,
+   ``below4g`` :since:`since 7.3.0 (QEMU only)`.
 ``maxMemory``
    The run time maximum memory allocation of the guest. The initial memory
    specified by either the ``<memory>`` element or the NUMA cell size
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index a2e5c50c1d..8f2ac1ad33 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -643,6 +643,11 @@
               <ref name="virOnOff"/>
             </attribute>
           </optional>
+          <optional>
+            <attribute name="below4g">
+              <ref name="unsignedLong"/>
+            </attribute>
+          </optional>
         </element>
       </optional>
       <optional>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index a72d58f488..272fcd894e 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -19786,6 +19786,10 @@ virDomainDefParseMemory(virDomainDef *def,
                              &def->mem.max_memory, false, false) < 0)
         goto error;
 
+    if (virDomainParseMemory("./memory[1]/@below4g", NULL, ctxt,
+                             &def->mem.max_ram_below_4g, false, true) < 0)
+        goto error;
+
     if (virXPathUInt("string(./maxMemory[1]/@slots)", ctxt, &def->mem.memory_slots) == -2) {
         virReportError(VIR_ERR_XML_ERROR, "%s",
                        _("Failed to parse memory slot count"));
@@ -28844,6 +28848,8 @@ virDomainDefFormatInternalSetRootName(virDomainDef *def,
     if (def->mem.dump_core)
         virBufferAsprintf(buf, " dumpCore='%s'",
                           virTristateSwitchTypeToString(def->mem.dump_core));
+    if (def->mem.max_ram_below_4g > 0)
+        virBufferAsprintf(buf, " below4g='%llu'", def->mem.max_ram_below_4g);
     virBufferAsprintf(buf, " unit='KiB'>%llu</memory>\n",
                       virDomainDefGetMemoryTotal(def));
 
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 4838687edf..a939d43e93 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -2597,6 +2597,9 @@ struct _virDomainMemtune {
     unsigned long long max_memory; /* in kibibytes */
     unsigned int memory_slots; /* maximum count of RAM memory slots */
 
+    /* maximum memory below the 4GiB boundary (32bit boundary) */
+    unsigned long long max_ram_below_4g; /* in kibibytes */
+
     bool nosharepages;
     bool locked;
     int dump_core; /* enum virTristateSwitch */
diff --git a/src/conf/domain_validate.c b/src/conf/domain_validate.c
index 686b9e8d16..afa9e2e821 100644
--- a/src/conf/domain_validate.c
+++ b/src/conf/domain_validate.c
@@ -1384,6 +1384,19 @@ virDomainDefMemtuneValidate(const virDomainDef *def)
         }
     }
 
+    if (mem->max_ram_below_4g &&
+        mem->max_ram_below_4g < 1024) {
+        virReportError(VIR_ERR_XML_DETAIL, "%s",
+                       _("maximum memory size below the 4GiB boundary must be "
+                         "greater than or equal to 1MiB"));
+        return -1;
+    } else if (mem->max_ram_below_4g > 4 * 1024 * 1024) {
+        virReportError(VIR_ERR_XML_DETAIL, "%s",
+                       _("maximum memory size below the 4GiB boundary must be "
+                         "less than or equal to 4GiB"));
+        return -1;
+    }
+
     return 0;
 }
 
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index be93182092..c69ad781e6 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -6961,6 +6961,10 @@ qemuBuildMachineCommandLine(virCommand *cmd,
                           cfg->dumpGuestCore ? "on" : "off");
     }
 
+    if (def->mem.max_ram_below_4g > 0)
+        virBufferAsprintf(&buf, ",max-ram-below-4g=%llu",
+                          def->mem.max_ram_below_4g * 1024);
+
     if (def->mem.nosharepages)
         virBufferAddLit(&buf, ",mem-merge=off");
 
diff --git a/tests/qemuxml2argvdata/memory-below4g.args b/tests/qemuxml2argvdata/memory-below4g.args
new file mode 100644
index 0000000000..f55386a2a2
--- /dev/null
+++ b/tests/qemuxml2argvdata/memory-below4g.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-i386 \
+-name QEMUGuest1 \
+-S \
+-machine pc,accel=tcg,usb=off,dump-guest-core=off,max-ram-below-4g=112197632 \
+-m 214 \
+-realtime mlock=off \
+-smp 1,sockets=1,cores=1,threads=1 \
+-uuid c7a5fdbd-edaf-9455-926a-d65c16db1809 \
+-display none \
+-no-user-config \
+-nodefaults \
+-chardev socket,id=charmonitor,path=/tmp/lib/domain--1-QEMUGuest1/monitor.sock,server=on,wait=off \
+-mon chardev=charmonitor,id=monitor,mode=control \
+-rtc base=utc \
+-no-shutdown \
+-no-acpi \
+-usb \
+-drive file=/dev/HostVG/QEMUGuest1,format=raw,if=none,id=drive-ide0-0-0 \
+-device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 \
+-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3
diff --git a/tests/qemuxml2argvdata/memory-below4g.xml b/tests/qemuxml2argvdata/memory-below4g.xml
new file mode 100644
index 0000000000..a843ef72a2
--- /dev/null
+++ b/tests/qemuxml2argvdata/memory-below4g.xml
@@ -0,0 +1,26 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory below4g='109568' unit='MiB'>214</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>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-i386</emulator>
+    <disk type='block' device='disk'>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <controller type='usb' index='0'/>
+    <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
+  </devices>
+</domain>
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index f0efe98d7e..d26455d36c 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -1055,6 +1055,7 @@ mymain(void)
     driver.config->dumpGuestCore = true;
     DO_TEST("machine-core-off", NONE);
     driver.config->dumpGuestCore = false;
+    DO_TEST("memory-below4g", NONE);
     DO_TEST("machine-smm-opt",
             QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE,
             QEMU_CAPS_DEVICE_PCI_BRIDGE,
diff --git a/tests/qemuxml2xmloutdata/memory-below4g.xml b/tests/qemuxml2xmloutdata/memory-below4g.xml
new file mode 100644
index 0000000000..44f58fc93b
--- /dev/null
+++ b/tests/qemuxml2xmloutdata/memory-below4g.xml
@@ -0,0 +1,37 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory below4g='109568' unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>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-i386</emulator>
+    <disk type='block' device='disk'>
+      <driver name='qemu' type='raw'/>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <controller type='usb' index='0'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
+    </controller>
+    <controller type='ide' index='0'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
+    </controller>
+    <controller type='pci' index='0' model='pci-root'/>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <audio id='1' type='none'/>
+    <memballoon model='virtio'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
+    </memballoon>
+  </devices>
+</domain>
diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c
index c37de0c704..21e491cdda 100644
--- a/tests/qemuxml2xmltest.c
+++ b/tests/qemuxml2xmltest.c
@@ -220,6 +220,7 @@ mymain(void)
     DO_TEST_CAPS_LATEST("genid-auto");
     DO_TEST("machine-core-on", NONE);
     DO_TEST("machine-core-off", NONE);
+    DO_TEST("memory-below4g", NONE);
     DO_TEST("machine-loadparm-multiple-disks-nets-s390", NONE);
     DO_TEST("default-kvm-host-arch", NONE);
     DO_TEST("default-qemu-host-arch", NONE);
-- 
2.24.3 (Apple Git-128)