[PULL 13/33] target/s390x: Base support for cpacf protected keys and pckmo

[Eric Farman <farman@linux.ibm.com>]

From: Harald Freudenberger <freude@linux.ibm.com>

Add base support for cpacf protected key handling.
Add support for the pckmo subfunctions PCKMO-Encrypt-AES-128-Key,
PCKMO-Encrypt-AES-192-Key and PCKMO-Encrypt-AES-256-Key which deal
with protected keys. These pckmo subfunctions derive a protected key
from an AES clear key by encrypting it with an internal AES wrapping
key. More details about protected keys can be found in the
"z/Architecture Prinziples of Operation" document.

The qemu version provided here is only a fake intended to make
protected key available for developing and testing purpose:
* The protected key is 'derived' from the clear key by xoring
  the fixed pattern 0xAAAA... onto the key value.
* The AES Wrapping Key Verification Pattern is a fixed
  value of 32 bytes 0x0F0A0C0E0F0A0C0E...

Add preprocessor defines for the xor pattern and wkvp used to
construct ('encrypt') a protected key from a clear key value with
this implementation. Also add some static functions to 'encrypt'
from clear key to protected key and 'decrypt' back to cpacf_aes.c.

The preprocessor defines shall be used later in testcases to
construct and decode protected keys.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Tested-by: Holger Dengler <dengler@linux.ibm.com>
Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/qemu-devel/20260824083204.40877-14-freude@linux.ibm.com
Signed-off-by: Eric Farman <farman@linux.ibm.com>
---
 target/s390x/gen-features.c      |  3 ++
 target/s390x/tcg/cpacf-arch.h    | 25 +++++++++++++
 target/s390x/tcg/cpacf.h         |  2 +
 target/s390x/tcg/cpacf_aes.c     | 64 ++++++++++++++++++++++++++++++++
 target/s390x/tcg/crypto_helper.c | 21 +++++++++++
 target/s390x/tcg/translate.c     | 14 +++++--
 6 files changed, 126 insertions(+), 3 deletions(-)

diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
index ad99f9ff85..e00255af67 100644
--- a/target/s390x/gen-features.c
+++ b/target/s390x/gen-features.c
@@ -942,6 +942,9 @@ static uint16_t qemu_MAX[] = {
     S390_FEAT_KMCTR_AES_256,
     S390_FEAT_PCC_XTS_AES_128,
     S390_FEAT_PCC_XTS_AES_256,
+    S390_FEAT_PCKMO_AES_128,
+    S390_FEAT_PCKMO_AES_192,
+    S390_FEAT_PCKMO_AES_256,
 };
 
 /****** END FEATURE DEFS ******/
diff --git a/target/s390x/tcg/cpacf-arch.h b/target/s390x/tcg/cpacf-arch.h
index f92e4b44e3..cd51169c45 100644
--- a/target/s390x/tcg/cpacf-arch.h
+++ b/target/s390x/tcg/cpacf-arch.h
@@ -223,4 +223,29 @@
 #define CPACF_KDSA_PSIGN_ED25519   48
 #define CPACF_KDSA_PSIGN_ED448     52
 
+/*
+ * Support for protected key cpacf functions. Note that this is
+ * a fake implementation intended for debugging and development.
+ * Do not use for production load !
+ */
+
+/*
+ * Hard coded pattern xored with the AES clear key
+ * to 'produce' the protected key.
+ */
+#define PROTKEY_XOR_PATTERN { \
+    0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, \
+    0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, \
+    0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, \
+    0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA }
+
+/*
+ * Hard coded wkvp ("Wrapping Key Verification Pattern")
+ */
+#define PROTKEY_WKVP { \
+    0x0F, 0x0A, 0x0C, 0x0E, 0x0F, 0x0A, 0x0C, 0x0E, \
+    0x0F, 0x0A, 0x0C, 0x0E, 0x0F, 0x0A, 0x0C, 0x0E, \
+    0x0F, 0x0A, 0x0C, 0x0E, 0x0F, 0x0A, 0x0C, 0x0E, \
+    0x0F, 0x0A, 0x0C, 0x0E, 0x0F, 0x0A, 0x0C, 0x0E }
+
 #endif /* S390X_CPACF_ARCH_H */
diff --git a/target/s390x/tcg/cpacf.h b/target/s390x/tcg/cpacf.h
index 5013e19907..1964de5b6d 100644
--- a/target/s390x/tcg/cpacf.h
+++ b/target/s390x/tcg/cpacf.h
@@ -38,5 +38,7 @@ int cpacf_aes_xts(CPUS390XState *env, const int mmu_idx, uintptr_t ra,
                   uint64_t param_addr, uint64_t *dst_ptr_reg,
                   uint64_t *src_ptr_reg, uint64_t *src_len_reg,
                   uint32_t type, uint8_t fc, uint8_t mod);
+int cpacf_aes_pckmo(CPUS390XState *env, const int mmu_idx, uintptr_t ra,
+                    uint64_t param_addr, uint8_t fc);
 
 #endif /* S390X_CPACF_H */
diff --git a/target/s390x/tcg/cpacf_aes.c b/target/s390x/tcg/cpacf_aes.c
index f705bd6677..5a835016df 100644
--- a/target/s390x/tcg/cpacf_aes.c
+++ b/target/s390x/tcg/cpacf_aes.c
@@ -454,3 +454,67 @@ int cpacf_aes_xts(CPUS390XState *env, const int mmu_idx, uintptr_t ra,
 
     return !len ? 0 : 3;
 }
+
+/*
+ * Support for protected key cpacf functions. Note that this is
+ * a fake implementation intended for debugging and development.
+ * Do not use for production load !
+ */
+
+/*
+ * Hard coded pattern xored with the AES clear key
+ * to 'produce' the protected key.
+ */
+static const uint8_t protkey_xor_pattern[32] = PROTKEY_XOR_PATTERN;
+
+/*
+ * Hard coded wkvp ("Wrapping Key Verification Pattern")
+ */
+static const uint8_t protkey_wkvp[32] = PROTKEY_WKVP;
+
+/*
+ * 'encrypt' the clear key value into a protected key
+ * by xor-ing the protkey_xor_pattern onto it.
+ */
+static void encrypt_clrkey(uint8_t *key, int keysize)
+{
+    for (int i = 0; i < keysize; i++) {
+        key[i] ^= protkey_xor_pattern[i];
+    }
+}
+
+int cpacf_aes_pckmo(CPUS390XState *env, const int mmu_idx, uintptr_t ra,
+                    uint64_t param_addr, uint8_t fc)
+{
+    uint8_t key[32];
+    int keysize;
+
+    switch (fc) {
+    case CPACF_PCKMO_ENC_AES_128_KEY:
+        keysize = 16;
+        break;
+    case CPACF_PCKMO_ENC_AES_192_KEY:
+        keysize = 24;
+        break;
+    case CPACF_PCKMO_ENC_AES_256_KEY:
+        keysize = 32;
+        break;
+    default:
+        g_assert_not_reached();
+    }
+
+    /* fetch key from param block */
+    read_guest_wrap_u8(env, mmu_idx, ra, param_addr, key, keysize);
+
+    /* 'derive' the protected key from the clear key */
+    encrypt_clrkey(key, keysize);
+
+    /* store the protected key into param block */
+    write_guest_wrap_u8(env, mmu_idx, ra, param_addr, key, keysize);
+    /* followed by the fake wkvp */
+    write_guest_wrap_u8(env, mmu_idx, ra,
+                        param_addr + keysize,
+                        protkey_wkvp, sizeof(protkey_wkvp));
+
+    return 0;
+}
diff --git a/target/s390x/tcg/crypto_helper.c b/target/s390x/tcg/crypto_helper.c
index 2bd39f8978..191b30e0f8 100644
--- a/target/s390x/tcg/crypto_helper.c
+++ b/target/s390x/tcg/crypto_helper.c
@@ -205,6 +205,24 @@ static int cpacf_pcc(CPUS390XState *env, const int mmu_idx, uintptr_t ra,
     return rc;
 }
 
+static int cpacf_pckmo(CPUS390XState *env, const int mmu_idx, uintptr_t ra,
+                       uint8_t fc)
+{
+    int rc = 0;
+
+    switch (fc) {
+    case CPACF_PCKMO_ENC_AES_128_KEY:
+    case CPACF_PCKMO_ENC_AES_192_KEY:
+    case CPACF_PCKMO_ENC_AES_256_KEY:
+        rc = cpacf_aes_pckmo(env, mmu_idx, ra, env->regs[1], fc);
+        break;
+    default:
+        tcg_s390_program_interrupt(env, PGM_SPECIFICATION, ra);
+    }
+
+    return rc;
+}
+
 uint32_t HELPER(msa)(CPUS390XState *env, uint32_t r1, uint32_t r2, uint32_t r3,
                      uint32_t type)
 {
@@ -264,6 +282,9 @@ uint32_t HELPER(msa)(CPUS390XState *env, uint32_t r1, uint32_t r2, uint32_t r3,
     case S390_FEAT_TYPE_PCC:
         rc = cpacf_pcc(env, mmu_idx, ra, fc);
         break;
+    case S390_FEAT_TYPE_PCKMO:
+        rc = cpacf_pckmo(env, mmu_idx, ra, fc);
+        break;
     case S390_FEAT_TYPE_PPNO:
         rc = cpacf_ppno(env, mmu_idx, ra, r1, r2, r3, fc);
         break;
diff --git a/target/s390x/tcg/translate.c b/target/s390x/tcg/translate.c
index 7e74e9742f..474d604ed1 100644
--- a/target/s390x/tcg/translate.c
+++ b/target/s390x/tcg/translate.c
@@ -2558,6 +2558,7 @@ static DisasJumpType op_msa(DisasContext *s, DisasOps *o)
     int r2 = have_field(s, r2) ? get_field(s, r2) : 0;
     int r3 = have_field(s, r3) ? get_field(s, r3) : 0;
     TCGv_i32 t_r1, t_r2, t_r3, type;
+    bool update_cc = true;
 
     switch (s->insn->data) {
     case S390_FEAT_TYPE_KMA:
@@ -2590,8 +2591,10 @@ static DisasJumpType op_msa(DisasContext *s, DisasOps *o)
             gen_program_exception(s, PGM_SPECIFICATION);
             return DISAS_NORETURN;
         }
-        /* FALL THROUGH */
+        break;
     case S390_FEAT_TYPE_PCKMO:
+        update_cc = false;
+        /* FALL THROUGH */
     case S390_FEAT_TYPE_PCC:
         break;
     default:
@@ -2602,8 +2605,13 @@ static DisasJumpType op_msa(DisasContext *s, DisasOps *o)
     t_r2 = tcg_constant_i32(r2);
     t_r3 = tcg_constant_i32(r3);
     type = tcg_constant_i32(s->insn->data);
-    gen_helper_msa(cc_op, tcg_env, t_r1, t_r2, t_r3, type);
-    set_cc_static(s);
+    if (update_cc) {
+        gen_helper_msa(cc_op, tcg_env, t_r1, t_r2, t_r3, type);
+        set_cc_static(s);
+    } else {
+        TCGv_i32 cc_dummy = tcg_temp_new_i32();
+        gen_helper_msa(cc_dummy, tcg_env, t_r1, t_r2, t_r3, type);
+    }
     return DISAS_NEXT;
 }
 
-- 
2.55.0