[PATCH v12 30/35] hw/s390x/ipl: Handle secure boot with multiple boot devices

[Zhuoying Cai <zycai@linux.ibm.com>]

The current approach to enable secure boot relies on providing
secure-boot and boot-certs parameters of s390-ccw-virtio machine
type option, which apply to all boot devices.

With the possibility of multiple boot devices, secure boot expects all
provided devices to be supported and eligible (e.g.,
virtio-blk/virtio-scsi using the SCSI scheme).

If multiple boot devices are provided and include an unsupported (e.g.,
ECKD, VFIO) or a non-eligible (e.g., Net) device, the boot process will
terminate with an error logged to the console.

Signed-off-by: Zhuoying Cai <zycai@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
---
 hw/s390x/ipl.c          | 89 +++++++++++++++++++++++++++++------------
 pc-bios/s390-ccw/main.c |  3 --
 2 files changed, 64 insertions(+), 28 deletions(-)

diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
index da826908c1..0d6a783d9f 100644
--- a/hw/s390x/ipl.c
+++ b/hw/s390x/ipl.c
@@ -472,6 +472,68 @@ static bool s390_secure_boot_enabled(void)
     return S390_CCW_MACHINE(qdev_get_machine())->secure_boot;
 }
 
+static bool s390_validate_secure_boot_device(int devtype, Error **errp)
+{
+    switch (devtype) {
+    case CCW_DEVTYPE_VFIO:
+       error_setg(errp, "Passthrough (vfio) CCW device does not support secure boot!");
+       return false;
+    case CCW_DEVTYPE_VIRTIO_NET:
+       error_setg(errp, "Virtio net boot device does not support secure boot!");
+       return false;
+    default:
+       return true;
+    }
+}
+
+static void s390_set_secure_boot_flags(IplParameterBlock *iplb,
+                                       bool secure_boot, bool audit_mode)
+{
+    if (!secure_boot && !audit_mode) {
+        return;
+    }
+
+    /*
+     * If secure-boot is enabled, then toggle the secure IPL flags (SIPL) to
+     * trigger secure boot in the s390 BIOS.
+     *
+     * Boot process will terminate if any error occurs during secure boot.
+     */
+    if (secure_boot) {
+        iplb->hdr_flags |= DIAG308_IPIB_FLAGS_SIPL;
+    }
+
+    /*
+     * For both secure boot and audit mode, enable the IPL Information
+     * Report (IPLIR) flag so that the firmware generates an IPL
+     * Information Report Block (IIRB).
+     *
+     * Results of secure boot will be stored in IIRB.
+     *
+     * Extend the IPL parameter block to its maximum length to ensure
+     * sufficient space for the BIOS to populate the IIRB.
+     */
+    iplb->hdr_flags |= DIAG308_IPIB_FLAGS_IPLIR;
+    iplb->len = cpu_to_be32(S390_IPLB_MAX_LEN);
+}
+
+static void s390_apply_secure_boot(IplParameterBlock *iplb, int devtype,
+                                   bool secure_boot, bool audit_mode)
+{
+    Error *local_error = NULL;
+
+    if (!secure_boot && !audit_mode) {
+        return;
+    }
+
+    if (!s390_validate_secure_boot_device(devtype, &local_error)) {
+        error_report_err(local_error);
+        exit(1);
+    }
+
+    s390_set_secure_boot_flags(iplb, secure_boot, audit_mode);
+}
+
 static bool s390_build_iplb(DeviceState *dev_st, IplParameterBlock *iplb)
 {
     CcwDevice *ccw_dev = NULL;
@@ -528,31 +590,8 @@ static bool s390_build_iplb(DeviceState *dev_st, IplParameterBlock *iplb)
         s390_ipl_convert_loadparm((char *)lp, iplb->loadparm);
         iplb->flags |= DIAG308_FLAGS_LP_VALID;
 
-        /*
-         * If secure-boot is enabled, then toggle the secure IPL flags to
-         * trigger secure boot in the s390 BIOS.
-         *
-         * Boot process will terminate if any error occurs during secure boot.
-         *
-         * If SIPL is on, IPLIR must also be on.
-         */
-        if (s390_secure_boot_enabled()) {
-            iplb->hdr_flags |= (DIAG308_IPIB_FLAGS_SIPL | DIAG308_IPIB_FLAGS_IPLIR);
-            iplb->len = cpu_to_be32(S390_IPLB_MAX_LEN);
-        }
-        /*
-         * Secure boot in audit mode will perform
-         * if certificate(s) exist in the key store.
-         *
-         * IPL Information Report Block (IIRB) will exist
-         * for secure boot in audit mode.
-         *
-         * Results of secure boot will be stored in IIRB.
-         */
-        else if (s390_has_certificate()) {
-            iplb->hdr_flags |= DIAG308_IPIB_FLAGS_IPLIR;
-            iplb->len = cpu_to_be32(S390_IPLB_MAX_LEN);
-        }
+        s390_apply_secure_boot(iplb, devtype, s390_secure_boot_enabled(),
+                               s390_has_certificate());
 
         return true;
     }
diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c
index 687946c471..3eccdf1c99 100644
--- a/pc-bios/s390-ccw/main.c
+++ b/pc-bios/s390-ccw/main.c
@@ -305,9 +305,6 @@ static void ipl_ccw_device(void)
     switch (cutype) {
     case CU_TYPE_DASD_3990:
     case CU_TYPE_DASD_2107:
-        IPL_assert((boot_mode == ZIPL_BOOT_MODE_NORMAL),
-                    "Passthrough (vfio) CCW device does not support secure boot!");
-
         dasd_ipl(blk_schid, cutype);
         break;
     case CU_TYPE_VIRTIO:
-- 
2.54.0