[PATCH v6 19/28] pc-bios/s390-ccw: Add signature verification for secure IPL in audit mode

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

Enable secure IPL in audit mode, which performs signature verification,
but any error does not terminate the boot process. Only warnings will be
logged to the console instead.

Add a comp_len variable to store the length of a segment in
zipl_load_segment. comp_len variable is necessary to store the
calculated segment length and is used during signature verification.
Return the length on success, or a negative return code on failure.

Secure IPL in audit mode requires at least one certificate provided in
the key store along with necessary facilities (Secure IPL Facility,
Certificate Store Facility and secure IPL extension support).

Note: Secure IPL in audit mode is implemented for the SCSI scheme of
virtio-blk/virtio-scsi devices.

Signed-off-by: Zhuoying Cai <zycai@linux.ibm.com>
---
 docs/system/s390x/secure-ipl.rst |  36 +++
 pc-bios/s390-ccw/Makefile        |   3 +-
 pc-bios/s390-ccw/bootmap.c       |  39 +++-
 pc-bios/s390-ccw/bootmap.h       |  11 +
 pc-bios/s390-ccw/main.c          |   9 +
 pc-bios/s390-ccw/s390-ccw.h      |  15 ++
 pc-bios/s390-ccw/sclp.c          |  44 ++++
 pc-bios/s390-ccw/sclp.h          |   6 +
 pc-bios/s390-ccw/secure-ipl.c    | 371 +++++++++++++++++++++++++++++++
 pc-bios/s390-ccw/secure-ipl.h    |  99 +++++++++
 10 files changed, 630 insertions(+), 3 deletions(-)
 create mode 100644 pc-bios/s390-ccw/secure-ipl.c
 create mode 100644 pc-bios/s390-ccw/secure-ipl.h

diff --git a/docs/system/s390x/secure-ipl.rst b/docs/system/s390x/secure-ipl.rst
index 92c1bb2153..701594b9de 100644
--- a/docs/system/s390x/secure-ipl.rst
+++ b/docs/system/s390x/secure-ipl.rst
@@ -19,3 +19,39 @@ Note: certificate files must have a .pem extension.
     qemu-system-s390x -machine s390-ccw-virtio, \
                                boot-certs.0.path=/.../qemu/certs, \
                                boot-certs.1.path=/another/path/cert.pem ...
+
+
+IPL Modes
+=========
+
+The concept of IPL Modes are introduced to differentiate between the IPL configurations.
+These modes are mutually exclusive and enabled based on the ``boot-certs`` option on the
+QEMU command line.
+
+Normal Mode
+-----------
+
+The absence of certificates will attempt to IPL a guest without secure IPL operations.
+No checks are performed, and no warnings/errors are reported. This is the default mode.
+
+Configuration:
+
+.. code-block:: shell
+
+    qemu-system-s390x -machine s390-ccw-virtio ...
+
+Audit Mode
+----------
+
+With *only* the presence of certificates in the store, it is assumed that secure
+boot operations should be performed with errors reported as warnings. As such,
+the secure IPL operations will be performed, and any errors that stem from these
+operations will report a warning via the SCLP console.
+
+Configuration:
+
+.. code-block:: shell
+
+    qemu-system-s390x -machine s390-ccw-virtio, \
+                               boot-certs.0.path=/.../qemu/certs, \
+                               boot-certs.1.path=/another/path/cert.pem ...
diff --git a/pc-bios/s390-ccw/Makefile b/pc-bios/s390-ccw/Makefile
index a0f24c94a8..603761a857 100644
--- a/pc-bios/s390-ccw/Makefile
+++ b/pc-bios/s390-ccw/Makefile
@@ -34,7 +34,8 @@ QEMU_DGFLAGS = -MMD -MP -MT $@ -MF $(@D)/$(*F).d
 .PHONY : all clean build-all distclean
 
 OBJECTS = start.o main.o bootmap.o jump2ipl.o sclp.o menu.o netmain.o \
-	  virtio.o virtio-net.o virtio-scsi.o virtio-blkdev.o cio.o dasd-ipl.o
+	  virtio.o virtio-net.o virtio-scsi.o virtio-blkdev.o cio.o dasd-ipl.o \
+	  secure-ipl.o
 
 SLOF_DIR := $(SRC_PATH)/../../roms/SLOF
 
diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c
index 4f54c643ff..3922e7cdde 100644
--- a/pc-bios/s390-ccw/bootmap.c
+++ b/pc-bios/s390-ccw/bootmap.c
@@ -15,6 +15,7 @@
 #include "bootmap.h"
 #include "virtio.h"
 #include "bswap.h"
+#include "secure-ipl.h"
 
 #ifdef DEBUG
 /* #define DEBUG_FALLBACK */
@@ -617,7 +618,7 @@ static int ipl_eckd(void)
  * Returns: length of the segment on sucess,
  *          negative value on error.
  */
-static int zipl_load_segment(ComponentEntry *entry, uint64_t address)
+int zipl_load_segment(ComponentEntry *entry, uint64_t address)
 {
     const int max_entries = (MAX_SECTOR_SIZE / sizeof(ScsiBlockPtr));
     ScsiBlockPtr *bprs = (void *)sec;
@@ -735,7 +736,19 @@ static int zipl_run(ScsiBlockPtr *pte)
     /* Load image(s) into RAM */
     entry = (ComponentEntry *)(&header[1]);
 
-    if (zipl_run_normal(&entry, tmp_sec)) {
+    switch (boot_mode) {
+    case ZIPL_BOOT_MODE_SECURE_AUDIT:
+        if (zipl_run_secure(&entry, tmp_sec)) {
+            return -1;
+        }
+        break;
+    case ZIPL_BOOT_MODE_NORMAL:
+        if (zipl_run_normal(&entry, tmp_sec)) {
+            return -1;
+        }
+        break;
+    default:
+        puts("Unknown boot mode");
         return -1;
     }
 
@@ -1101,17 +1114,35 @@ static int zipl_load_vscsi(void)
  * IPL starts here
  */
 
+ZiplBootMode zipl_mode(uint8_t hdr_flags)
+{
+    bool sipl_set = hdr_flags & DIAG308_IPIB_FLAGS_SIPL;
+    bool iplir_set = hdr_flags & DIAG308_IPIB_FLAGS_IPLIR;
+
+    if (!sipl_set && iplir_set) {
+        return ZIPL_BOOT_MODE_SECURE_AUDIT;
+    }
+
+    return ZIPL_BOOT_MODE_NORMAL;
+}
+
 void zipl_load(void)
 {
     VDev *vdev = virtio_get_device();
 
     if (vdev->is_cdrom) {
+        if (boot_mode == ZIPL_BOOT_MODE_SECURE_AUDIT) {
+            panic("Secure boot from ISO image is not supported!");
+        }
         ipl_iso_el_torito();
         puts("Failed to IPL this ISO image!");
         return;
     }
 
     if (virtio_get_device_type() == VIRTIO_ID_NET) {
+        if (boot_mode == ZIPL_BOOT_MODE_SECURE_AUDIT) {
+            panic("Virtio net boot device does not support secure boot!");
+        }
         netmain();
         puts("Failed to IPL from this network!");
         return;
@@ -1122,6 +1153,10 @@ void zipl_load(void)
         return;
     }
 
+    if (boot_mode == ZIPL_BOOT_MODE_SECURE_AUDIT) {
+        panic("ECKD boot device does not support secure boot!");
+    }
+
     switch (virtio_get_device_type()) {
     case VIRTIO_ID_BLOCK:
         zipl_load_vblk();
diff --git a/pc-bios/s390-ccw/bootmap.h b/pc-bios/s390-ccw/bootmap.h
index 95943441d3..90fd530256 100644
--- a/pc-bios/s390-ccw/bootmap.h
+++ b/pc-bios/s390-ccw/bootmap.h
@@ -88,9 +88,18 @@ typedef struct BootMapTable {
     BootMapPointer entry[];
 } __attribute__ ((packed)) BootMapTable;
 
+#define DER_SIGNATURE_FORMAT 1
+
+typedef struct SignatureInformation {
+    uint8_t format;
+    uint8_t reserved[3];
+    uint32_t sig_len;
+} __attribute__((packed)) SignatureInformation;
+
 typedef union ComponentEntryData {
     uint64_t load_psw;
     uint64_t load_addr;
+    SignatureInformation sig_info;
 } ComponentEntryData;
 
 typedef struct ComponentEntry {
@@ -113,6 +122,8 @@ typedef struct ScsiMbr {
     ScsiBlockPtr pt;   /* block pointer to program table */
 } __attribute__ ((packed)) ScsiMbr;
 
+int zipl_load_segment(ComponentEntry *entry, uint64_t address);
+
 #define ZIPL_MAGIC              "zIPL"
 #define ZIPL_MAGIC_EBCDIC       "\xa9\xc9\xd7\xd3"
 #define IPL1_MAGIC "\xc9\xd7\xd3\xf1" /* == "IPL1" in EBCDIC */
diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c
index c9328f1c51..668660e64d 100644
--- a/pc-bios/s390-ccw/main.c
+++ b/pc-bios/s390-ccw/main.c
@@ -28,6 +28,7 @@ IplParameterBlock *iplb;
 bool have_iplb;
 static uint16_t cutype;
 LowCore *lowcore; /* Yes, this *is* a pointer to address 0 */
+ZiplBootMode boot_mode;
 
 #define LOADPARM_PROMPT "PROMPT  "
 #define LOADPARM_EMPTY  "        "
@@ -272,9 +273,17 @@ static int virtio_setup(void)
 
 static void ipl_boot_device(void)
 {
+    if (boot_mode == ZIPL_BOOT_MODE_UNSPECIFIED) {
+        boot_mode = zipl_mode(iplb->hdr_flags);
+    }
+
     switch (cutype) {
     case CU_TYPE_DASD_3990:
     case CU_TYPE_DASD_2107:
+        if (boot_mode == ZIPL_BOOT_MODE_SECURE_AUDIT) {
+            panic("Passthrough (vfio) device does not support secure boot!");
+        }
+
         dasd_ipl(blk_schid, cutype);
         break;
     case CU_TYPE_VIRTIO:
diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h
index b1dc35cded..c2ba40d067 100644
--- a/pc-bios/s390-ccw/s390-ccw.h
+++ b/pc-bios/s390-ccw/s390-ccw.h
@@ -39,6 +39,9 @@ typedef unsigned long long u64;
 #define MIN_NON_ZERO(a, b) ((a) == 0 ? (b) : \
                             ((b) == 0 ? (a) : (MIN(a, b))))
 #endif
+#ifndef ROUND_UP
+#define ROUND_UP(n, d) (((n) + (d) - 1) & -(0 ? (n) : (d)))
+#endif
 
 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
 
@@ -64,6 +67,8 @@ void sclp_print(const char *string);
 void sclp_set_write_mask(uint32_t receive_mask, uint32_t send_mask);
 void sclp_setup(void);
 void sclp_get_loadparm_ascii(char *loadparm);
+bool sclp_is_diag320_on(void);
+bool sclp_is_sipl_on(void);
 int sclp_read(char *str, size_t count);
 
 /* virtio.c */
@@ -76,6 +81,16 @@ int virtio_read(unsigned long sector, void *load_addr);
 /* bootmap.c */
 void zipl_load(void);
 
+typedef enum ZiplBootMode {
+    ZIPL_BOOT_MODE_UNSPECIFIED = 0,
+    ZIPL_BOOT_MODE_NORMAL = 1,
+    ZIPL_BOOT_MODE_SECURE_AUDIT = 2,
+} ZiplBootMode;
+
+extern ZiplBootMode boot_mode;
+
+ZiplBootMode zipl_mode(uint8_t hdr_flags);
+
 /* jump2ipl.c */
 void write_reset_psw(uint64_t psw);
 int jump_to_IPL_code(uint64_t address);
diff --git a/pc-bios/s390-ccw/sclp.c b/pc-bios/s390-ccw/sclp.c
index 4a07de018d..0b03c3164f 100644
--- a/pc-bios/s390-ccw/sclp.c
+++ b/pc-bios/s390-ccw/sclp.c
@@ -113,6 +113,50 @@ void sclp_get_loadparm_ascii(char *loadparm)
     }
 }
 
+static void sclp_get_fac134(uint8_t *fac134)
+{
+
+    ReadInfo *sccb = (void *)_sccb;
+
+    memset((char *)_sccb, 0, sizeof(ReadInfo));
+    sccb->h.length = SCCB_SIZE;
+    if (!sclp_service_call(SCLP_CMDW_READ_SCP_INFO, sccb)) {
+        *fac134 = sccb->fac134;
+    }
+}
+
+bool sclp_is_diag320_on(void)
+{
+    uint8_t fac134 = 0;
+
+    sclp_get_fac134(&fac134);
+    return fac134 & SCCB_FAC134_DIAG320_BIT;
+}
+
+/*
+ * Get fac_ipl (byte 136 and byte 137 of the SCLP Read Info block)
+ * for IPL device facilities.
+ */
+static void sclp_get_fac_ipl(uint16_t *fac_ipl)
+{
+
+    ReadInfo *sccb = (void *)_sccb;
+
+    memset((char *)_sccb, 0, sizeof(ReadInfo));
+    sccb->h.length = SCCB_SIZE;
+    if (!sclp_service_call(SCLP_CMDW_READ_SCP_INFO, sccb)) {
+        *fac_ipl = sccb->fac_ipl;
+    }
+}
+
+bool sclp_is_sipl_on(void)
+{
+    uint16_t fac_ipl = 0;
+
+    sclp_get_fac_ipl(&fac_ipl);
+    return fac_ipl & SCCB_FAC_IPL_SIPL_BIT;
+}
+
 int sclp_read(char *str, size_t count)
 {
     ReadEventData *sccb = (void *)_sccb;
diff --git a/pc-bios/s390-ccw/sclp.h b/pc-bios/s390-ccw/sclp.h
index 64b53cad29..cf147f4634 100644
--- a/pc-bios/s390-ccw/sclp.h
+++ b/pc-bios/s390-ccw/sclp.h
@@ -50,6 +50,8 @@ typedef struct SCCBHeader {
 } __attribute__((packed)) SCCBHeader;
 
 #define SCCB_DATA_LEN (SCCB_SIZE - sizeof(SCCBHeader))
+#define SCCB_FAC134_DIAG320_BIT 0x4
+#define SCCB_FAC_IPL_SIPL_BIT 0x4000
 
 typedef struct ReadInfo {
     SCCBHeader h;
@@ -57,6 +59,10 @@ typedef struct ReadInfo {
     uint8_t rnsize;
     uint8_t reserved[13];
     uint8_t loadparm[LOADPARM_LEN];
+    uint8_t reserved1[102];
+    uint8_t fac134;
+    uint8_t reserved2;
+    uint16_t fac_ipl;
 } __attribute__((packed)) ReadInfo;
 
 typedef struct SCCB {
diff --git a/pc-bios/s390-ccw/secure-ipl.c b/pc-bios/s390-ccw/secure-ipl.c
new file mode 100644
index 0000000000..8eab19cb09
--- /dev/null
+++ b/pc-bios/s390-ccw/secure-ipl.c
@@ -0,0 +1,371 @@
+/*
+ * S/390 Secure IPL
+ *
+ * Functions to support IPL in secure boot mode (DIAG 320, DIAG 508,
+ * signature verification, and certificate handling).
+ *
+ * For secure IPL overview: docs/system/s390x/secure-ipl.rst
+ * For secure IPL technical: docs/specs/s390x-secure-ipl.rst
+ *
+ * Copyright 2025 IBM Corp.
+ * Author(s): Zhuoying Cai <zycai@linux.ibm.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include "bootmap.h"
+#include "s390-ccw.h"
+#include "secure-ipl.h"
+
+uint8_t vcssb_data[VCSSB_MIN_LEN] __attribute__((__aligned__(PAGE_SIZE)));
+
+VCStorageSizeBlock *zipl_secure_get_vcssb(void)
+{
+    VCStorageSizeBlock *vcssb;
+    int rc;
+
+    if (!(sclp_is_diag320_on() && is_cert_store_facility_supported())) {
+        puts("Certificate Store Facility is not supported by the hypervisor!");
+        return NULL;
+    }
+
+    vcssb = (VCStorageSizeBlock *)vcssb_data;
+    /* avoid retrieving vcssb multiple times */
+    if (vcssb->length >= VCSSB_MIN_LEN) {
+        return vcssb;
+    }
+
+    vcssb->length = VCSSB_MIN_LEN;
+    rc = diag320(vcssb, DIAG_320_SUBC_QUERY_VCSI);
+    if (rc != DIAG_320_RC_OK) {
+        return NULL;
+    }
+
+    return vcssb;
+}
+
+static uint32_t get_certs_length(void)
+{
+    VCStorageSizeBlock *vcssb;
+    uint32_t len;
+
+    vcssb = zipl_secure_get_vcssb();
+    if (vcssb == NULL) {
+        return 0;
+    }
+
+    len = vcssb->total_vcb_len - VCB_HEADER_LEN - vcssb->total_vc_ct * VCE_HEADER_LEN;
+
+    return len;
+}
+
+static uint32_t request_certificate(uint8_t *cert, uint8_t index)
+{
+    VCStorageSizeBlock *vcssb;
+    VCBlock *vcb;
+    VCEntry *vce;
+    uint64_t rc = 0;
+    uint32_t cert_len = 0;
+
+    /* Get Verification Certificate Storage Size block with DIAG320 subcode 1 */
+    vcssb = zipl_secure_get_vcssb();
+    if (vcssb == NULL) {
+        return 0;
+    }
+
+    /*
+     * Request single entry
+     * Fill input fields of single-entry VCB
+     */
+    vcb = malloc(MAX_SECTOR_SIZE * 4);
+    vcb->in_len = ROUND_UP(vcssb->max_single_vcb_len, PAGE_SIZE);
+    vcb->first_vc_index = index + 1;
+    vcb->last_vc_index = index + 1;
+
+    rc = diag320(vcb, DIAG_320_SUBC_STORE_VC);
+    if (rc == DIAG_320_RC_OK) {
+        if (vcb->out_len == VCB_HEADER_LEN) {
+            puts("No certificate entry");
+            goto out;
+        }
+        if (vcb->remain_ct != 0) {
+            puts("Not enough memory to store all requested certificates");
+            goto out;
+        }
+
+        vce = (VCEntry *)vcb->vce_buf;
+        if (!is_vce_cert_valid(vce->flags, vce->len)) {
+            puts("Invalid certificate");
+            goto out;
+        }
+
+        cert_len = vce->cert_len;
+        memcpy(cert, (uint8_t *)vce + vce->cert_offset, vce->cert_len);
+    }
+
+out:
+    free(vcb);
+    return cert_len;
+}
+
+static void cert_list_add(IplSignatureCertificateList *certs, int cert_index,
+                          uint8_t *cert, uint64_t cert_len)
+{
+    if (cert_index > MAX_CERTIFICATES - 1) {
+        printf("Warning: Ignoring cert entry [%d] because it's over %d entires\n",
+                cert_index + 1, MAX_CERTIFICATES);
+        return;
+    }
+
+    certs->cert_entries[cert_index].addr = (uint64_t)cert;
+    certs->cert_entries[cert_index].len = cert_len;
+    certs->ipl_info_header.len += sizeof(certs->cert_entries[cert_index]);
+}
+
+static void comp_list_add(IplDeviceComponentList *comps, int comp_index,
+                          int cert_index, uint64_t comp_addr,
+                          uint64_t comp_len, uint8_t flags)
+{
+    if (comp_index > MAX_CERTIFICATES - 1) {
+        printf("Warning: Ignoring comp entry [%d] because it's over %d entires\n",
+                comp_index + 1, MAX_CERTIFICATES);
+        return;
+    }
+
+    comps->device_entries[comp_index].addr = comp_addr;
+    comps->device_entries[comp_index].len = comp_len;
+    comps->device_entries[comp_index].flags = flags;
+    comps->device_entries[comp_index].cert_index = cert_index;
+    comps->ipl_info_header.len += sizeof(comps->device_entries[comp_index]);
+}
+
+static int update_iirb(IplDeviceComponentList *comps, IplSignatureCertificateList *certs)
+{
+    IplInfoReportBlock *iirb;
+    IplDeviceComponentList *iirb_comps;
+    IplSignatureCertificateList *iirb_certs;
+    uint32_t iirb_hdr_len;
+    uint32_t comps_len;
+    uint32_t certs_len;
+
+    if (iplb->len % 8 != 0) {
+        panic("IPL parameter block length field value is not multiple of 8 bytes");
+    }
+
+    iirb_hdr_len = sizeof(IplInfoReportBlockHeader);
+    comps_len = comps->ipl_info_header.len;
+    certs_len = certs->ipl_info_header.len;
+    if ((comps_len + certs_len + iirb_hdr_len) > sizeof(IplInfoReportBlock)) {
+        puts("Not enough space to hold all components and certificates in IIRB");
+        return -1;
+    }
+
+    /* IIRB immediately follows IPLB */
+    iirb = &ipl_data.iirb;
+    iirb->hdr.len = iirb_hdr_len;
+
+    /* Copy IPL device component list after IIRB Header */
+    iirb_comps = (IplDeviceComponentList *) iirb->info_blks;
+    memcpy(iirb_comps, comps, comps_len);
+
+    /* Update IIRB length */
+    iirb->hdr.len += comps_len;
+
+    /* Copy IPL sig cert list after IPL device component list */
+    iirb_certs = (IplSignatureCertificateList *) (iirb->info_blks +
+                                                  iirb_comps->ipl_info_header.len);
+    memcpy(iirb_certs, certs, certs_len);
+
+    /* Update IIRB length */
+    iirb->hdr.len += certs_len;
+
+    return 0;
+}
+
+static bool secure_ipl_supported(void)
+{
+    if (!sclp_is_sipl_on()) {
+        puts("Secure IPL Facility is not supported by the hypervisor!");
+        return false;
+    }
+
+    if (!is_secure_ipl_extension_supported()) {
+        puts("Secure IPL extensions are not supported by the hypervisor!");
+        return false;
+    }
+
+    if (!(sclp_is_diag320_on() && is_cert_store_facility_supported())) {
+        puts("Certificate Store Facility is not supported by the hypervisor!");
+        return false;
+    }
+
+    return true;
+}
+
+static void init_lists(IplDeviceComponentList *comps, IplSignatureCertificateList *certs)
+{
+    comps->ipl_info_header.ibt = IPL_IBT_COMPONENTS;
+    comps->ipl_info_header.len = sizeof(comps->ipl_info_header);
+
+    certs->ipl_info_header.ibt = IPL_IBT_CERTIFICATES;
+    certs->ipl_info_header.len = sizeof(certs->ipl_info_header);
+}
+
+static uint32_t zipl_load_signature(ComponentEntry *entry, uint64_t sig_sec)
+{
+    uint32_t sig_len;
+
+    if (zipl_load_segment(entry, sig_sec) < 0) {
+        return -1;
+    }
+
+    if (entry->compdat.sig_info.format != DER_SIGNATURE_FORMAT) {
+        puts("Signature is not in DER format");
+        return -1;
+    }
+    sig_len = entry->compdat.sig_info.sig_len;
+
+    return sig_len;
+}
+
+static int handle_certificate(int *cert_table, uint8_t **cert,
+                             uint64_t cert_len, uint8_t cert_idx,
+                             IplSignatureCertificateList *certs, int cert_index)
+{
+    bool unused;
+
+    unused = cert_table[cert_idx] == -1;
+    if (unused) {
+        if (request_certificate(*cert, cert_idx)) {
+            cert_list_add(certs, cert_index, *cert, cert_len);
+            cert_table[cert_idx] = cert_index;
+            *cert += cert_len;
+        } else {
+            puts("Could not get certificate");
+            return -1;
+        }
+
+        /* increment cert_index for the next cert entry */
+        return ++cert_index;
+    }
+
+    return cert_index;
+}
+
+int zipl_run_secure(ComponentEntry **entry_ptr, uint8_t *tmp_sec)
+{
+    IplDeviceComponentList comps;
+    IplSignatureCertificateList certs;
+    ComponentEntry *entry = *entry_ptr;
+    uint8_t *cert = NULL;
+    uint64_t *sig = NULL;
+    int cert_index = 0;
+    int comp_index = 0;
+    uint64_t comp_addr;
+    int comp_len;
+    uint32_t sig_len = 0;
+    uint64_t cert_len = -1;
+    uint8_t cert_idx = -1;
+    bool verified;
+    uint32_t certs_len;
+    /*
+     * Store indices of cert entry that have already used for signature verification
+     * to prevent allocating the same certificate multiple times.
+     * cert_table index: index of certificate from qemu cert store used for verification
+     * cert_table value: index of cert entry in cert list that contains the certificate
+     */
+    int cert_table[MAX_CERTIFICATES] = { [0 ... MAX_CERTIFICATES - 1] = -1};
+    int signed_count = 0;
+
+    if (!secure_ipl_supported()) {
+        return -1;
+    }
+
+    init_lists(&comps, &certs);
+    certs_len = get_certs_length();
+    cert = malloc(certs_len);
+    sig = malloc(MAX_SECTOR_SIZE);
+
+    while (entry->component_type != ZIPL_COMP_ENTRY_EXEC) {
+        switch (entry->component_type) {
+        case ZIPL_COMP_ENTRY_SIGNATURE:
+            if (sig_len) {
+                goto out;
+            }
+
+            sig_len = zipl_load_signature(entry, (uint64_t)sig);
+            if (sig_len < 0) {
+                goto out;
+            }
+            break;
+        case ZIPL_COMP_ENTRY_LOAD:
+            comp_addr = entry->compdat.load_addr;
+            comp_len = zipl_load_segment(entry, comp_addr);
+            if (comp_len < 0) {
+                goto out;
+            }
+
+            if (!sig_len) {
+                break;
+            }
+
+            verified = verify_signature(comp_len, comp_addr, sig_len, (uint64_t)sig,
+                                        &cert_len, &cert_idx);
+
+            if (verified) {
+                cert_index = handle_certificate(cert_table, &cert, cert_len, cert_idx,
+                                                &certs, cert_index);
+                if (cert_index == -1) {
+                    goto out;
+                }
+
+                puts("Verified component");
+                comp_list_add(&comps, comp_index, cert_table[cert_idx],
+                              comp_addr, comp_len,
+                              S390_IPL_COMPONENT_FLAG_SC | S390_IPL_COMPONENT_FLAG_CSV);
+            } else {
+                comp_list_add(&comps, comp_index, -1,
+                              comp_addr, comp_len,
+                              S390_IPL_COMPONENT_FLAG_SC);
+                zipl_secure_handle("Could not verify component");
+            }
+
+            comp_index++;
+            signed_count += 1;
+            /* After a signature is used another new one can be accepted */
+            sig_len = 0;
+            break;
+        default:
+            puts("Unknown component entry type");
+            return -1;
+        }
+
+        entry++;
+
+        if ((uint8_t *)(&entry[1]) > tmp_sec + MAX_SECTOR_SIZE) {
+            puts("Wrong entry value");
+            return -EINVAL;
+        }
+    }
+
+    if (signed_count == 0) {
+        zipl_secure_handle("Secure boot is on, but components are not signed");
+    }
+
+    if (update_iirb(&comps, &certs)) {
+        zipl_secure_handle("Failed to write IPL Information Report Block");
+    }
+
+    *entry_ptr = entry;
+    free(sig);
+
+    return 0;
+out:
+    free(cert);
+    free(sig);
+
+    return -1;
+}
diff --git a/pc-bios/s390-ccw/secure-ipl.h b/pc-bios/s390-ccw/secure-ipl.h
new file mode 100644
index 0000000000..a264a44349
--- /dev/null
+++ b/pc-bios/s390-ccw/secure-ipl.h
@@ -0,0 +1,99 @@
+/*
+ * S/390 Secure IPL
+ *
+ * Copyright 2025 IBM Corp.
+ * Author(s): Zhuoying Cai <zycai@linux.ibm.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef _PC_BIOS_S390_CCW_SECURE_IPL_H
+#define _PC_BIOS_S390_CCW_SECURE_IPL_H
+
+#include <diag320.h>
+#include <diag508.h>
+
+VCStorageSizeBlock *zipl_secure_get_vcssb(void);
+int zipl_run_secure(ComponentEntry **entry_ptr, uint8_t *tmp_sec);
+
+static inline void zipl_secure_handle(const char *message)
+{
+    switch (boot_mode) {
+    case ZIPL_BOOT_MODE_SECURE_AUDIT:
+        IPL_check(false, message);
+        break;
+    default:
+        break;
+    }
+}
+
+static inline uint64_t diag320(void *data, unsigned long subcode)
+{
+    register unsigned long addr asm("0") = (unsigned long)data;
+    register unsigned long rc asm("1") = 0;
+
+    asm volatile ("diag %0,%2,0x320\n"
+                  : "+d" (addr), "+d" (rc)
+                  : "d" (subcode)
+                  : "memory", "cc");
+    return rc;
+}
+
+static inline bool is_vce_cert_valid(uint8_t vce_flags, uint32_t vce_len)
+{
+    return (vce_flags & DIAG_320_VCE_FLAGS_VALID) && (vce_len > VCE_INVALID_LEN);
+}
+
+static inline bool is_cert_store_facility_supported(void)
+{
+    uint32_t d320_ism;
+
+    diag320(&d320_ism, DIAG_320_SUBC_QUERY_ISM);
+    return (d320_ism & DIAG_320_ISM_QUERY_SUBCODES) &&
+           (d320_ism & DIAG_320_ISM_QUERY_VCSI) &&
+           (d320_ism & DIAG_320_ISM_STORE_VC);
+}
+
+static inline uint64_t _diag508(void *data, unsigned long subcode)
+{
+    register unsigned long addr asm("0") = (unsigned long)data;
+    register unsigned long rc asm("1") = 0;
+
+    asm volatile ("diag %0,%2,0x508\n"
+                  : "+d" (addr), "+d" (rc)
+                  : "d" (subcode)
+                  : "memory", "cc");
+    return rc;
+}
+
+static inline bool is_secure_ipl_extension_supported(void)
+{
+    uint64_t d508_subcodes;
+
+    d508_subcodes = _diag508(NULL, DIAG_508_SUBC_QUERY_SUBC);
+    return d508_subcodes & DIAG_508_SUBC_SIG_VERIF;
+}
+
+static inline bool verify_signature(uint64_t comp_len, uint64_t comp_addr,
+                                    uint64_t sig_len, uint64_t sig_addr,
+                                    uint64_t *cert_len, uint8_t *cert_idx)
+{
+    Diag508SigVerifBlock svb;
+
+    svb.length = sizeof(Diag508SigVerifBlock);
+    svb.version = 0;
+    svb.comp_len = comp_len;
+    svb.comp_addr = comp_addr;
+    svb.sig_len = sig_len;
+    svb.sig_addr = sig_addr;
+
+    if (_diag508(&svb, DIAG_508_SUBC_SIG_VERIF) == DIAG_508_RC_OK) {
+        *cert_len = svb.cert_len;
+        *cert_idx = svb.cert_store_index;
+        return true;
+    }
+
+    return false;
+}
+
+#endif /* _PC_BIOS_S390_CCW_SECURE_IPL_H */
-- 
2.50.1