diff mbox series

[RFC] target/ppc: Implement hashst(p) and hashchk(p) instructions

Message ID 20220622171943.90786-1-victor.colombo@eldorado.org.br (mailing list archive)
State New, archived
Headers show
Series [RFC] target/ppc: Implement hashst(p) and hashchk(p) instructions | expand

Commit Message

Víctor Colombo June 22, 2022, 5:19 p.m. UTC
Implementation for instructions hashst, hashchk, and its privileged
versions.

It was decided to implement the hash algorithm from ground up in this
patch exactly as described in Power ISA.

Signed-off-by: Víctor Colombo <victor.colombo@eldorado.org.br>

---

RFC because I need some feedback on if the approach of implementing
the algorithm is a good idea. Also, it seems that the kernel/kvm are
not implementing the necessary registers?

What do you think about the choice to implement the hash algorithm
from the ground up, following the SIMON-like algorithm presented in
Power ISA? IIUC, this algorithm is not the same as the original[1].
Other options would be to use other algorithm already implemented
in QEMU, or even make this instruction a nop for all Power versions.

Based-on: ppc-next, with 
    <20220620210540.112153-1-leandro.lupori@eldorado.org.br> and
    <20220615192006.3075821-1-lucas.coutinho@eldorado.org.br>
    applied on top. The relevant patches are:
    [PATCH 01/11] target/ppc: receive DisasContext explicitly in GEN_PRIV
    [PATCH 02/11] target/ppc: add macros to check privilege level

[1] https://eprint.iacr.org/2013/404.pdf
---
 linux-headers/asm-powerpc/kvm.h            |  3 +
 target/ppc/cpu.h                           |  2 +
 target/ppc/cpu_init.c                      |  7 ++
 target/ppc/excp_helper.c                   | 82 ++++++++++++++++++++++
 target/ppc/helper.h                        |  4 ++
 target/ppc/insn32.decode                   | 10 +++
 target/ppc/translate.c                     |  5 ++
 target/ppc/translate/fixedpoint-impl.c.inc | 34 +++++++++
 8 files changed, 147 insertions(+)
diff mbox series

Patch

diff --git a/linux-headers/asm-powerpc/kvm.h b/linux-headers/asm-powerpc/kvm.h
index 9f18fa090f..4ae4718143 100644
--- a/linux-headers/asm-powerpc/kvm.h
+++ b/linux-headers/asm-powerpc/kvm.h
@@ -646,6 +646,9 @@  struct kvm_ppc_cpu_char {
 #define KVM_REG_PPC_SIER3	(KVM_REG_PPC | KVM_REG_SIZE_U64 | 0xc3)
 #define KVM_REG_PPC_DAWR1	(KVM_REG_PPC | KVM_REG_SIZE_U64 | 0xc4)
 #define KVM_REG_PPC_DAWRX1	(KVM_REG_PPC | KVM_REG_SIZE_U64 | 0xc5)
+/* FIXME: KVM hasn't exposed these registers yet */
+#define KVM_REG_PPC_HASHKEYR    (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x00)
+#define KVM_REG_PPC_HASHPKEYR   (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x00)
 
 /* Transactional Memory checkpointed state:
  * This is all GPRs, all VSX regs and a subset of SPRs
diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 6d78078f37..d982b779ca 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -1665,6 +1665,8 @@  void ppc_compat_add_property(Object *obj, const char *name,
 #define SPR_BOOKE_GIVOR14     (0x1BD)
 #define SPR_TIR               (0x1BE)
 #define SPR_PTCR              (0x1D0)
+#define SPR_POWER_HASHKEYR    (0x1D4)
+#define SPR_POWER_HASHPKEYR   (0x1D5)
 #define SPR_BOOKE_SPEFSCR     (0x200)
 #define SPR_Exxx_BBEAR        (0x201)
 #define SPR_Exxx_BBTAR        (0x202)
diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index b802bbb641..3ec9e4a27f 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -6484,6 +6484,13 @@  static void init_proc_POWER10(CPUPPCState *env)
                         spr_read_generic, spr_write_generic,
                         KVM_REG_PPC_PSSCR, 0);
 
+    spr_register_kvm(env, SPR_POWER_HASHKEYR, "HASHPKEYR",
+        SPR_NOACCESS, SPR_NOACCESS, &spr_read_generic, &spr_write_generic,
+        KVM_REG_PPC_HASHKEYR, 0x0);
+    spr_register_kvm(env, SPR_POWER_HASHPKEYR, "HASHPKEYR",
+        SPR_NOACCESS, SPR_NOACCESS, &spr_read_generic, &spr_write_generic,
+        KVM_REG_PPC_HASHPKEYR, 0x0);
+
     /* env variables */
     env->dcache_line_size = 128;
     env->icache_line_size = 128;
diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
index cb752b184a..0998e8374e 100644
--- a/target/ppc/excp_helper.c
+++ b/target/ppc/excp_helper.c
@@ -2174,6 +2174,88 @@  void helper_td(CPUPPCState *env, target_ulong arg1, target_ulong arg2,
 #endif
 #endif
 
+static uint32_t helper_SIMON_LIKE_32_64(uint32_t x, uint64_t key, uint32_t lane)
+{
+    const uint16_t c = 0xfffc;
+    const uint64_t z0 = 0xfa2561cdf44ac398ULL;
+    uint16_t z = 0, temp;
+    uint16_t k[32], eff_k[32], xleft[33], xright[33], fxleft[32];
+
+    for (int i = 3; i >= 0; i--) {
+        k[i] = key & 0xffff;
+        key >>= 16;
+    }
+    xleft[0] = x & 0xffff;
+    xright[0] = (x >> 16) & 0xffff;
+
+    for (int i = 0; i < 28; i++) {
+        z = (z0 >> (63 - i)) & 1;
+        temp = ror16(k[i + 3], 3) ^ k[i + 1];
+        k[i + 4] = c ^ z ^ k[i] ^ temp ^ ror16(temp, 1);
+    }
+
+    for (int i = 0; i < 8; i++) {
+        eff_k[4 * i + 0] = k[4 * i + ((0 + lane) % 4)];
+        eff_k[4 * i + 1] = k[4 * i + ((1 + lane) % 4)];
+        eff_k[4 * i + 2] = k[4 * i + ((2 + lane) % 4)];
+        eff_k[4 * i + 3] = k[4 * i + ((3 + lane) % 4)];
+    }
+
+    for (int i = 0; i < 32; i++) {
+        fxleft[i] = (rol16(xleft[i], 1) &
+            rol16(xleft[i], 8)) ^ rol16(xleft[i], 2);
+        xleft[i + 1] = xright[i] ^ fxleft[i] ^ eff_k[i];
+        xright[i + 1] = xleft[i];
+    }
+
+    return (((uint32_t)xright[32]) << 16) | xleft[32];
+}
+
+static uint64_t hash_digest(uint64_t ra, uint64_t rb, uint64_t key)
+{
+    uint64_t stage0_h = 0ULL, stage0_l = 0ULL;
+    uint64_t stage1_h, stage1_l;
+
+    for (int i = 0; i < 4; i++) {
+        stage0_h |= ror64(rb & 0xff, 8 * (2 * i + 1));
+        stage0_h |= ((ra >> 32) & 0xff) << (8 * 2 * i);
+        stage0_l |= ror64((rb >> 32) & 0xff, 8 * (2 * i + 1));
+        stage0_l |= (ra & 0xff) << (8 * 2 * i);
+        rb >>= 8;
+        ra >>= 8;
+    }
+
+    stage1_h = (uint64_t)helper_SIMON_LIKE_32_64(stage0_h >> 32, key, 0) << 32;
+    stage1_h |= helper_SIMON_LIKE_32_64(stage0_h, key, 1);
+    stage1_l = (uint64_t)helper_SIMON_LIKE_32_64(stage0_l >> 32, key, 2) << 32;
+    stage1_l |= helper_SIMON_LIKE_32_64(stage0_l, key, 3);
+
+    return stage1_h ^ stage1_l;
+}
+
+#define HELPER_HASH(op, key, store)                                           \
+void helper_##op(CPUPPCState *env, target_ulong ea, target_ulong ra,          \
+                 target_ulong rb)                                             \
+{                                                                             \
+    uint64_t chash = hash_digest(ra, rb, key), lhash;                         \
+                                                                              \
+    if (store) {                                                              \
+        cpu_stq_data_ra(env, ea, chash, GETPC());                             \
+    } else {                                                                  \
+        lhash = cpu_ldq_data_ra(env, ea, GETPC());                            \
+        if (lhash != chash) {                                                 \
+            /* hashes don't match, trap */                                    \
+            raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,                 \
+                POWERPC_EXCP_TRAP, GETPC());                                  \
+        }                                                                     \
+    }                                                                         \
+}
+
+HELPER_HASH(HASHST, env->spr[SPR_POWER_HASHKEYR], true)
+HELPER_HASH(HASHCHK, env->spr[SPR_POWER_HASHKEYR], false)
+HELPER_HASH(HASHSTP, env->spr[SPR_POWER_HASHPKEYR], true)
+HELPER_HASH(HASHCHKP, env->spr[SPR_POWER_HASHPKEYR], false)
+
 #if !defined(CONFIG_USER_ONLY)
 
 #ifdef CONFIG_TCG
diff --git a/target/ppc/helper.h b/target/ppc/helper.h
index 4287f41880..c7ff3eb169 100644
--- a/target/ppc/helper.h
+++ b/target/ppc/helper.h
@@ -4,6 +4,10 @@  DEF_HELPER_FLAGS_4(tw, TCG_CALL_NO_WG, void, env, tl, tl, i32)
 #if defined(TARGET_PPC64)
 DEF_HELPER_FLAGS_4(td, TCG_CALL_NO_WG, void, env, tl, tl, i32)
 #endif
+DEF_HELPER_4(HASHST, void, env, tl, tl, tl)
+DEF_HELPER_4(HASHCHK, void, env, tl, tl, tl)
+DEF_HELPER_4(HASHSTP, void, env, tl, tl, tl)
+DEF_HELPER_4(HASHCHKP, void, env, tl, tl, tl)
 #if !defined(CONFIG_USER_ONLY)
 DEF_HELPER_2(store_msr, void, env, tl)
 DEF_HELPER_1(rfi, void, env)
diff --git a/target/ppc/insn32.decode b/target/ppc/insn32.decode
index b36a093828..e0fc9ecb7f 100644
--- a/target/ppc/insn32.decode
+++ b/target/ppc/insn32.decode
@@ -157,6 +157,9 @@ 
 @X_TSX          ...... ..... ra:5 rb:5 .......... .             &X rt=%x_rt_tsx
 @X_TSXP         ...... ..... ra:5 rb:5 .......... .             &X rt=%rt_tsxp
 
+%x_dw           0:1 21:5 !function=dw_compose_ea
+@X_DW           ...... ..... ra:5 rb:5 .......... .             &X rt=%x_dw
+
 &X_frtp_vrb     frtp vrb
 @X_frtp_vrb     ...... ....0 ..... vrb:5 .......... .           &X_frtp_vrb frtp=%x_frtp
 
@@ -308,6 +311,13 @@  CNTTZDM         011111 ..... ..... ..... 1000111011 -   @X
 PDEPD           011111 ..... ..... ..... 0010011100 -   @X
 PEXTD           011111 ..... ..... ..... 0010111100 -   @X
 
+# Fixed-Point Hash Instructions
+
+HASHST          011111 ..... ..... ..... 1011010010 .   @X_DW
+HASHCHK         011111 ..... ..... ..... 1011110010 .   @X_DW
+HASHSTP         011111 ..... ..... ..... 1010010010 .   @X_DW
+HASHCHKP        011111 ..... ..... ..... 1010110010 .   @X_DW
+
 ### Float-Point Load Instructions
 
 LFS             110000 ..... ..... ................     @D
diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index a918575fa9..c870bbedad 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -6410,6 +6410,11 @@  static int times_16(DisasContext *ctx, int x)
     return x * 16;
 }
 
+static int64_t dw_compose_ea(DisasContext *ctx, int x)
+{
+    return deposit64(0xfffffffffffffe00, 3, 6, x);
+}
+
 /*
  * Helpers for trans_* functions to check for specific insns flags.
  * Use token pasting to ensure that we use the proper flag with the
diff --git a/target/ppc/translate/fixedpoint-impl.c.inc b/target/ppc/translate/fixedpoint-impl.c.inc
index 77d449c3cd..d0a8269ea6 100644
--- a/target/ppc/translate/fixedpoint-impl.c.inc
+++ b/target/ppc/translate/fixedpoint-impl.c.inc
@@ -489,3 +489,37 @@  static bool trans_PEXTD(DisasContext *ctx, arg_X *a)
 #endif
     return true;
 }
+
+static bool do_hash(DisasContext *ctx, arg_X *a, bool priv,
+    void (*helper)(TCGv_ptr, TCGv, TCGv, TCGv))
+{
+    TCGv ea;
+
+    if (!(ctx->insns_flags2 & PPC2_ISA310)) {
+        /* if version is before v3.1, this operation is a nop */
+        return true;
+    }
+
+    if (priv) {
+        /* if instruction is privileged but the context is in user space */
+        REQUIRE_SV(ctx);
+    }
+
+    if (unlikely(a->ra == 0)) {
+        /* if RA=0, the instruction form is invalid */
+        gen_invalid(ctx);
+        return true;
+    }
+
+    ea = do_ea_calc(ctx, a->ra, tcg_constant_tl(a->rt));
+    helper(cpu_env, ea, cpu_gpr[a->ra], cpu_gpr[a->rb]);
+
+    tcg_temp_free(ea);
+
+    return true;
+}
+
+TRANS(HASHST, do_hash, false, gen_helper_HASHST)
+TRANS(HASHCHK, do_hash, false, gen_helper_HASHCHK)
+TRANS(HASHSTP, do_hash, true, gen_helper_HASHSTP)
+TRANS(HASHCHKP, do_hash, true, gen_helper_HASHCHKP)