conf: Add support for keeping TPM emulator state

Currently, swtpm TPM state file is removed when a transient domain is
powered off or undefined. When we store TPM state on a shared storage
such as NFS and use transient domain, TPM states should be kept as it is.

Add per-TPM emulator option `persistent_sate` for keeping TPM state.
This option only works for the emulator type backend and looks as follows:

  <tpm model='tpm-tis'>
    <backend type='emulator' persistent_state='yes'/>
  </tpm>

Signed-off-by: Eiichi Tsukata <eiichi.tsukata@nutanix.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

docs/formatdomain.rst

@@ -6986,6 +6986,13 @@ Example: usage of the TPM Emulator
    -  '1.2' : creates a TPM 1.2
    -  '2.0' : creates a TPM 2.0
 
+``persistent_state``
+   The ``persistent_state`` attribute indicates whether 'swtpm' TPM state is
+   kept or not when a transient domain is powered off or undefined. This
+   option can be used for preserving TPM state. By default the value is ``no``.
+   This attribute only works with the ``emulator`` backend. The accepted values
+   are ``yes`` and ``no``. :since:`Since 7.0.0`
+
 ``encryption``
    The ``encryption`` element allows the state of a TPM emulator to be
    encrypted. The ``secret`` must reference a secret object that holds the

docs/schemas/domaincommon.rng

@@ -4766,6 +4766,14 @@
              <value>emulator</value>
           </attribute>
           <ref name="tpm-backend-emulator-encryption"/>
+          <optional>
+            <attribute name="persistent_state">
+              <choice>
+                <value>yes</value>
+                <value>no</value>
+              </choice>
+           </attribute>
+          </optional>
         </group>
       </choice>
       <choice>

src/conf/domain_conf.c

@@ -12220,6 +12220,12 @@ virDomainSmartcardDefParseXML(virDomainXMLOptionPtr xmlopt,
  *     <encryption secret='32ee7e76-2178-47a1-ab7b-269e6e348015'/>
  *   </backend>
  * </tpm>
+ *
+ * Emulator persistent_state is supported with the following:
+ *
+ * <tpm model='tpm-tis'>
+ *   <backend type='emulator' version='2.0' persistent_state='yes'>
+ * </tpm>
  */
 static virDomainTPMDefPtr
 virDomainTPMDefParseXML(virDomainXMLOptionPtr xmlopt,
@@ -12235,6 +12241,7 @@ virDomainTPMDefParseXML(virDomainXMLOptionPtr xmlopt,
     g_autofree char *backend = NULL;
     g_autofree char *version = NULL;
     g_autofree char *secretuuid = NULL;
+    g_autofree char *persistent_state = NULL;
     g_autofree xmlNodePtr *backends = NULL;
 
     def = g_new0(virDomainTPMDef, 1);
@@ -12307,6 +12314,16 @@ virDomainTPMDefParseXML(virDomainXMLOptionPtr xmlopt,
             }
             def->data.emulator.hassecretuuid = true;
         }
+
+        persistent_state = virXMLPropString(backends[0], "persistent_state");
+        if (persistent_state) {
+            if (virStringParseYesNo(persistent_state,
+                                    &def->data.emulator.persistent_state) < 0) {
+                virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                               _("Invalid persistent_state value, either 'yes' or 'no'"));
+                goto error;
+            }
+        }
         break;
     case VIR_DOMAIN_TPM_TYPE_LAST:
         goto error;
@@ -26025,6 +26042,8 @@ virDomainTPMDefFormat(virBufferPtr buf,
     case VIR_DOMAIN_TPM_TYPE_EMULATOR:
         virBufferAsprintf(buf, " version='%s'",
                           virDomainTPMVersionTypeToString(def->version));
+        if (def->data.emulator.persistent_state)
+            virBufferAddLit(buf, " persistent_state='yes'");
         if (def->data.emulator.hassecretuuid) {
             char uuidstr[VIR_UUID_STRING_BUFLEN];
             virBufferAddLit(buf, ">\n");

src/conf/domain_conf.h

@@ -1362,6 +1362,7 @@ struct _virDomainTPMDef {
             char *logfile;
             unsigned char secretuuid[VIR_UUID_BUFLEN];
             bool hassecretuuid;
+            bool persistent_state;
         } emulator;
     } data;
 };

src/qemu/qemu_tpm.c

@@ -729,6 +729,7 @@ qemuExtTPMCleanupHost(virDomainDefPtr def)
         if (def->tpms[i]->type != VIR_DOMAIN_TPM_TYPE_EMULATOR)
             continue;
 
+        if (!def->tpms[i]->data.emulator.persistent_state)
             qemuTPMDeleteEmulatorStorage(def->tpms[i]);
     }
 }

tests/qemuxml2argvdata/tpm-emulator-tpm2-pstate.x86_64-latest.args

@@ -0,0 +1,38 @@
+LC_ALL=C \
+PATH=/bin \
+HOME=/tmp/lib/domain--1-TPM-VM \
+USER=test \
+LOGNAME=test \
+XDG_DATA_HOME=/tmp/lib/domain--1-TPM-VM/.local/share \
+XDG_CACHE_HOME=/tmp/lib/domain--1-TPM-VM/.cache \
+XDG_CONFIG_HOME=/tmp/lib/domain--1-TPM-VM/.config \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu-system-x86_64 \
+-name guest=TPM-VM,debug-threads=on \
+-S \
+-object secret,id=masterKey0,format=raw,\
+file=/tmp/lib/domain--1-TPM-VM/master-key.aes \
+-machine pc-i440fx-2.12,accel=tcg,usb=off,dump-guest-core=off,\
+memory-backend=pc.ram \
+-cpu qemu64 \
+-m 2048 \
+-object memory-backend-ram,id=pc.ram,size=2147483648 \
+-overcommit mem-lock=off \
+-smp 1,sockets=1,cores=1,threads=1 \
+-uuid 11d7cd22-da89-3094-6212-079a48a309a1 \
+-display none \
+-no-user-config \
+-nodefaults \
+-chardev socket,id=charmonitor,fd=1729,server,nowait \
+-mon chardev=charmonitor,id=monitor,mode=control \
+-rtc base=utc \
+-no-shutdown \
+-boot menu=on,strict=on \
+-device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 \
+-tpmdev emulator,id=tpm-tpm0,chardev=chrtpm \
+-chardev socket,id=chrtpm,path=/dev/test \
+-device tpm-tis,tpmdev=tpm-tpm0,id=tpm0 \
+-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x2 \
+-sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,\
+resourcecontrol=deny \
+-msg timestamp=on

tests/qemuxml2argvdata/tpm-emulator-tpm2-pstate.xml

@@ -0,0 +1,30 @@
+<domain type='qemu'>
+  <name>TPM-VM</name>
+  <uuid>11d7cd22-da89-3094-6212-079a48a309a1</uuid>
+  <memory unit='KiB'>2097152</memory>
+  <currentMemory unit='KiB'>512288</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc-i440fx-2.12'>hvm</type>
+    <boot dev='hd'/>
+    <bootmenu enable='yes'/>
+  </os>
+  <features>
+    <acpi/>
+  </features>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</emulator>
+    <controller type='usb' index='0'/>
+    <controller type='pci' index='0' model='pci-root'/>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <tpm model='tpm-tis'>
+      <backend type='emulator' version='2.0' persistent_state='yes'/>
+    </tpm>
+    <memballoon model='virtio'/>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -2461,6 +2461,7 @@ mymain(void)
     DO_TEST_CAPS_LATEST("tpm-emulator");
     DO_TEST_CAPS_LATEST("tpm-emulator-tpm2");
     DO_TEST_CAPS_LATEST("tpm-emulator-tpm2-enc");
+    DO_TEST_CAPS_LATEST("tpm-emulator-tpm2-pstate");
     DO_TEST_CAPS_LATEST_PPC64("tpm-emulator-spapr");
 
     DO_TEST_PARSE_ERROR("pci-domain-invalid", NONE);

tests/qemuxml2xmloutdata/tpm-emulator-tpm2-pstate.x86_64-latest.xml

@@ -0,0 +1,37 @@
+<domain type='qemu'>
+  <name>TPM-VM</name>
+  <uuid>11d7cd22-da89-3094-6212-079a48a309a1</uuid>
+  <memory unit='KiB'>2097152</memory>
+  <currentMemory unit='KiB'>512288</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc-i440fx-2.12'>hvm</type>
+    <boot dev='hd'/>
+    <bootmenu enable='yes'/>
+  </os>
+  <features>
+    <acpi/>
+  </features>
+  <cpu mode='custom' match='exact' check='none'>
+    <model fallback='forbid'>qemu64</model>
+  </cpu>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</emulator>
+    <controller type='usb' index='0' model='piix3-uhci'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
+    </controller>
+    <controller type='pci' index='0' model='pci-root'/>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <tpm model='tpm-tis'>
+      <backend type='emulator' version='2.0' persistent_state='yes'/>
+    </tpm>
+    <memballoon model='virtio'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
+    </memballoon>
+  </devices>
+</domain>

tests/qemuxml2xmltest.c

@@ -761,6 +761,7 @@ mymain(void)
     DO_TEST_CAPS_LATEST("tpm-emulator");
     DO_TEST_CAPS_LATEST("tpm-emulator-tpm2");
     DO_TEST_CAPS_LATEST("tpm-emulator-tpm2-enc");
+    DO_TEST_CAPS_LATEST("tpm-emulator-tpm2-pstate");
 
     DO_TEST("metadata", NONE);
     DO_TEST("metadata-duplicate", NONE);