qemu: Enable secure boot

In qemu, enabling this feature boils down to adding the following
onto the command line:

  -global driver=cfi.pflash01,property=secure,value=on

However, there are some constraints resulting from the
implementation. For instance, System Management Mode (SMM) is
required to be enabled, the machine type must be q35-2.4 or
later, and the guest should be x86_64. While technically it is
possible to have 32 bit guests with secure boot, some non-trivial
CPU flags tuning is required (for instance lm and nx flags must
be prohibited). Given complexity of our CPU driver, this is not
trivial. Therefore I've chosen to forbid 32 bit guests for now.
If there's ever need, we can refine the check later.

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

src/qemu/qemu_command.c

@@ -8910,6 +8910,13 @@ qemuBuildDomainLoaderCommandLine(virCommandPtr cmd,
             goto cleanup;
         }
 
+        if (loader->secure == VIR_TRISTATE_BOOL_YES) {
+            virCommandAddArgList(cmd,
+                                 "-global",
+                                 "driver=cfi.pflash01,property=secure,value=on",
+                                 NULL);
+        }
+
         virBufferAsprintf(&buf,
                           "file=%s,if=pflash,format=raw,unit=%d",
                           loader->path, unit);

src/qemu/qemu_domain.c

@@ -2322,6 +2322,33 @@ qemuDomainDefValidate(const virDomainDef *def,
         return -1;
     }
 
+    if (def->os.loader &&
+        def->os.loader->secure == VIR_TRISTATE_BOOL_YES) {
+        /* These are the QEMU implementation limitations. But we
+         * have to live with them for now. */
+
+        if (!qemuDomainMachineIsQ35(def)) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                           _("Secure boot is supported with q35 machine types only"));
+            return -1;
+        }
+
+        /* Now, technically it is possible to have secure boot on
+         * 32bits too, but that would require some -cpu xxx magic
+         * too. Not worth it unless we are explicitly asked. */
+        if (def->os.arch != VIR_ARCH_X86_64) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                           _("Secure boot is supported for x86_64 architecture only"));
+            return -1;
+        }
+
+        if (def->features[VIR_DOMAIN_FEATURE_SMM] != VIR_TRISTATE_SWITCH_ON) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                           _("Secure boot requires SMM feature enabled"));
+            return -1;
+        }
+    }
+
     return 0;
 }
 

tests/qemuxml2argvdata/qemuxml2argv-bios-nvram-secure.args

@@ -0,0 +1,29 @@
+LC_ALL=C \
+PATH=/bin \
+HOME=/home/test \
+USER=test \
+LOGNAME=test \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu \
+-name test-bios \
+-S \
+-machine pc-q35-2.5,accel=tcg,smm=on \
+-global driver=cfi.pflash01,property=secure,value=on \
+-drive file=/usr/share/OVMF/OVMF_CODE.secboot.fd,if=pflash,format=raw,unit=0,\
+readonly=on \
+-drive file=/usr/share/OVMF/OVMF_VARS.fd,if=pflash,format=raw,unit=1 \
+-m 1024 \
+-smp 1,sockets=1,cores=1,threads=1 \
+-uuid 362d1fc1-df7d-193e-5c18-49a71bd1da66 \
+-nographic \
+-nodefaults \
+-monitor unix:/tmp/lib/domain--1-test-bios/monitor.sock,server,nowait \
+-boot c \
+-device i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x1e \
+-device pci-bridge,chassis_nr=2,id=pci.2,bus=pci.1,addr=0x0 \
+-device virtio-scsi-pci,id=scsi0,bus=pci.2,addr=0x1 \
+-drive file=/dev/HostVG/QEMUGuest1,format=raw,if=none,id=drive-scsi0-0-0-0 \
+-device scsi-disk,bus=scsi0.0,channel=0,scsi-id=0,lun=0,\
+drive=drive-scsi0-0-0-0,id=scsi0-0-0-0 \
+-serial pty \
+-device virtio-balloon-pci,id=balloon0,bus=pci.2,addr=0x2

tests/qemuxml2argvtest.c

@@ -685,6 +685,13 @@ mymain(void)
 
     DO_TEST("bios", QEMU_CAPS_SGA);
     DO_TEST("bios-nvram", NONE);
+    DO_TEST("bios-nvram-secure",
+            QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE,
+            QEMU_CAPS_DEVICE_PCI_BRIDGE,
+            QEMU_CAPS_ICH9_AHCI,
+            QEMU_CAPS_MACHINE_OPT,
+            QEMU_CAPS_MACHINE_SMM_OPT,
+            QEMU_CAPS_VIRTIO_SCSI);
     DO_TEST("clock-utc", QEMU_CAPS_NODEFCONFIG);
     DO_TEST("clock-localtime", NONE);
     DO_TEST("clock-localtime-basis-localtime", QEMU_CAPS_RTC);