s390x/diag: Introduce DIAG 320 for Certificate Store Facility
DIAGNOSE 320 is introduced to support Certificate Store (CS) Facility, which includes operations such as query certificate storage information and provide certificates in the certificate store. Currently, only subcode 0 is supported with this patch, which is used to query the Installed Subcodes Mask (ISM). This subcode is only supported when the CS facility is enabled. Availability of CS facility is determined by byte 134 bit 5 of the SCLP Read Info block. Byte 134's facilities cannot be represented without the availability of the extended-length-SCCB, so add it as a check for consistency. Note: secure IPL is not available for Secure Execution (SE) guests, as their images are already integrity protected, and an additional protection of the kernel by secure IPL is not necessary. This feature is available starting with the gen16 CPU model. Signed-off-by: Zhuoying Cai <zycai@linux.ibm.com> Reviewed-by: Collin Walling <walling@linux.ibm.com> Reviewed-by: Farhan Ali <alifm@linux.ibm.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Link: https://lore.kernel.org/qemu-devel/20260730214624.2328883-6-zycai@linux.ibm.com Signed-off-by: Eric Farman <farman@linux.ibm.com>
Zhuoying Cai committed
Jul 30, 2026 at 17:45 UTC
66deb271528020cdf8be4611c9562cf5d5dab73e
10 files changed
+106
docs/specs/s390x-secure-ipl.rst
+12
@@ -18,3 +18,15 @@ PEM Base64 data.
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Note: A maximum of 64 certificates are allowed to be stored in the certificate
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store.
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+
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+DIAGNOSE function code 'X'320' - Certificate Store Facility
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+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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+
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+DIAGNOSE 'X'320' is used to provide support for guest code to directly
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+query the s390 certificate store. Guest code may be the s390-ccw BIOS or
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+the guest kernel.
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+
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+Subcode 0 - query installed subcodes
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+ Returns a 256-bit installed subcodes mask (ISM) stored in the installed
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+ subcodes block (ISB). This mask indicates which subcodes are currently
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+ installed and available for use.
include/hw/s390x/ipl/diag320.h
new
+20
@@ -0,0 +1,20 @@
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+/*
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+ * S/390 DIAGNOSE 320 definitions and structures
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+ *
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+ * Copyright 2025 IBM Corp.
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+ * Author(s): Zhuoying Cai <zycai@linux.ibm.com>
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+ *
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+ * SPDX-License-Identifier: GPL-2.0-or-later
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+ */
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+
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+#ifndef S390X_DIAG320_H
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+#define S390X_DIAG320_H
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+
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+#define DIAG_320_SUBC_QUERY_ISM 0
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+
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+#define DIAG_320_RC_OK 0x0001
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+#define DIAG_320_RC_NOT_SUPPORTED 0x0102
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+
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+#define DIAG_320_ISM_QUERY_SUBCODES 0x80000000
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+
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+#endif
target/s390x/cpu_features.c
+1
@@ -147,6 +147,7 @@ void s390_fill_feat_block(const S390FeatBitmap features, S390FeatType type,
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break;
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case S390_FEAT_TYPE_SCLP_FAC134:
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clear_be_bit(s390_feat_def(S390_FEAT_DIAG_318)->bit, data);
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+ clear_be_bit(s390_feat_def(S390_FEAT_CERT_STORE)->bit, data);
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break;
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case S390_FEAT_TYPE_SCLP_FAC139:
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clear_be_bit(s390_feat_def(S390_FEAT_SIE_ASTFLEIE2)->bit, data);
target/s390x/cpu_features_def.h.inc
+1
@@ -138,6 +138,7 @@ DEF_FEAT(SIE_IBS, "ibs", SCLP_CONF_CHAR_EXT, 10, "SIE: Interlock-and-broadcast-s
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/* Features exposed via SCLP SCCB Facilities byte 134 (bit numbers relative to byte-134) */
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DEF_FEAT(DIAG_318, "diag318", SCLP_FAC134, 0, "Control program name and version codes")
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+DEF_FEAT(CERT_STORE, "cstore", SCLP_FAC134, 5, "Certificate Store functions")
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/* Features exposed via SCLP SCCB Facilities byte 139 (bit numbers relative to byte-139) */
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DEF_FEAT(SIE_ASTFLEIE2, "astfleie2", SCLP_FAC139, 1, "SIE: ASTFLE interpretation execution facility 2")
target/s390x/cpu_models.c
+2
@@ -248,6 +248,7 @@ bool s390_has_feat(S390Feat feat)
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if (s390_is_pv()) {
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switch (feat) {
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case S390_FEAT_DIAG_318:
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+ case S390_FEAT_CERT_STORE:
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case S390_FEAT_HPMA2:
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case S390_FEAT_SIE_F2:
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case S390_FEAT_SIE_SKEY:
@@ -506,6 +507,7 @@ static void check_consistency(const S390CPUModel *model)
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{ S390_FEAT_PTFF_STOUE, S390_FEAT_MULTIPLE_EPOCH },
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{ S390_FEAT_AP_QUEUE_INTERRUPT_CONTROL, S390_FEAT_AP },
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{ S390_FEAT_DIAG_318, S390_FEAT_EXTENDED_LENGTH_SCCB },
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+ { S390_FEAT_CERT_STORE, S390_FEAT_EXTENDED_LENGTH_SCCB },
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{ S390_FEAT_NNPA, S390_FEAT_VECTOR },
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{ S390_FEAT_RDP, S390_FEAT_LOCAL_TLB_CLEARING },
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{ S390_FEAT_UV_FEAT_AP, S390_FEAT_AP },
target/s390x/diag.c
+42
@@ -18,6 +18,7 @@
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#include "hw/watchdog/wdt_diag288.h"
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#include "system/cpus.h"
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#include "hw/s390x/ipl.h"
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+#include "hw/s390x/ipl/diag320.h"
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#include "hw/s390x/s390-virtio-ccw.h"
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#include "system/kvm.h"
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#include "kvm/kvm_s390x.h"
@@ -199,3 +200,44 @@ out:
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return false;
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}
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}
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+
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+void handle_diag_320(CPUS390XState *env, uint64_t r1, uint64_t r3, uintptr_t ra)
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+{
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+ S390CPU *cpu = env_archcpu(env);
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+ uint64_t subcode = env->regs[r3];
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+ uint64_t addr = env->regs[r1];
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+ uint32_t ism_word0;
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+
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+ if (env->psw.mask & PSW_MASK_PSTATE) {
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+ s390_program_interrupt(env, PGM_PRIVILEGED, ra);
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+ return;
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+ }
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+
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+ if (!s390_has_feat(S390_FEAT_CERT_STORE) ||
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+ (subcode & ~0x000ffULL) ||
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+ (r1 & 1)) {
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+ s390_program_interrupt(env, PGM_SPECIFICATION, ra);
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+ return;
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+ }
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+
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+ switch (subcode) {
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+ case DIAG_320_SUBC_QUERY_ISM:
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+ /*
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+ * The Installed Subcode Block (ISB) can be up 8 words in size,
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+ * but the current set of subcodes can fit within a single word
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+ * for now.
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+ */
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+ ism_word0 = cpu_to_be32(DIAG_320_ISM_QUERY_SUBCODES);
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+
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+ if (s390_cpu_virt_mem_write(cpu, addr, r1, &ism_word0, sizeof(ism_word0))) {
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+ s390_cpu_virt_mem_handle_exc(cpu, ra);
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+ return;
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+ }
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+
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+ env->regs[r1 + 1] = DIAG_320_RC_OK;
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+ break;
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+ default:
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+ env->regs[r1 + 1] = DIAG_320_RC_NOT_SUPPORTED;
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+ break;
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+ }
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+}
target/s390x/gen-features.c
+3
@@ -721,6 +721,7 @@ static uint16_t full_GEN16_GA1[] = {
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S390_FEAT_UV_FEAT_AP,
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S390_FEAT_UV_FEAT_AP_INTR,
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S390_FEAT_SIE_ASTFLEIE2,
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+ S390_FEAT_CERT_STORE,
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};
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static uint16_t full_GEN17_GA1[] = {
@@ -920,6 +921,8 @@ static uint16_t qemu_MAX[] = {
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S390_FEAT_KIMD_SHA_512,
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S390_FEAT_KLMD_SHA_512,
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S390_FEAT_PRNO_TRNG,
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+ S390_FEAT_EXTENDED_LENGTH_SCCB,
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+ S390_FEAT_CERT_STORE,
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};
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/****** END FEATURE DEFS ******/
target/s390x/kvm/kvm.c
+16
@@ -99,6 +99,7 @@
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#define DIAG_TIMEREVENT 0x288
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#define DIAG_IPL 0x308
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#define DIAG_SET_CONTROL_PROGRAM_CODES 0x318
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+#define DIAG_CERT_STORE 0x320
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#define DIAG_KVM_HYPERCALL 0x500
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#define DIAG_KVM_BREAKPOINT 0x501
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@@ -1531,6 +1532,16 @@ static void handle_diag_318(S390CPU *cpu, struct kvm_run *run)
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}
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}
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+static void kvm_handle_diag_320(S390CPU *cpu, struct kvm_run *run)
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+{
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+ uint64_t r1, r3;
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+
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+ r1 = (run->s390_sieic.ipa & 0x00f0) >> 4;
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+ r3 = run->s390_sieic.ipa & 0x000f;
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+
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+ handle_diag_320(&cpu->env, r1, r3, RA_IGNORED);
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+}
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+
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#define DIAG_KVM_CODE_MASK 0x000000000000ffff
1546
1547
static int handle_diag(S390CPU *cpu, struct kvm_run *run, uint32_t ipb)
@@ -1561,6 +1572,9 @@ static int handle_diag(S390CPU *cpu, struct kvm_run *run, uint32_t ipb)
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case DIAG_KVM_BREAKPOINT:
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r = handle_sw_breakpoint(cpu, run);
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break;
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+ case DIAG_CERT_STORE:
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+ kvm_handle_diag_320(cpu, run);
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+ break;
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default:
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trace_kvm_insn_diag(func_code);
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kvm_s390_program_interrupt(cpu, PGM_SPECIFICATION);
@@ -2472,6 +2486,8 @@ bool kvm_s390_get_host_cpu_model(S390CPUModel *model, Error **errp)
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set_bit(S390_FEAT_DIAG_318, model->features);
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}
2488
2489
+ set_bit(S390_FEAT_CERT_STORE, model->features);
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+
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/* Test for Ultravisor features that influence secure guest behavior */
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query_uv_feat_guest(model->features);
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target/s390x/s390x-internal.h
+2
@@ -388,6 +388,8 @@ int handle_diag_288(CPUS390XState *env, uint64_t r1, uint64_t r3);
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/* Return whether a CPU reset is pending */
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bool handle_diag_308(CPUS390XState *env, uint64_t r1, uint64_t r3,
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uintptr_t ra);
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+void handle_diag_320(CPUS390XState *env, uint64_t r1, uint64_t r3,
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+ uintptr_t ra);
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394
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/* translate.c */
target/s390x/tcg/misc_helper.c
+7
@@ -147,6 +147,13 @@ void HELPER(diag)(CPUS390XState *env, uint32_t r1, uint32_t r3, uint32_t num)
147
/* time bomb (watchdog) */
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r = handle_diag_288(env, r1, r3);
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break;
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+ case 0x320:
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+ /* cert store */
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+ bql_lock();
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+ handle_diag_320(env, r1, r3, GETPC());
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+ bql_unlock();
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+ r = 0;
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+ break;
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default:
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r = -1;
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break;