[RFC PATCH v9 04/23] target/arm: Implement ALLINT MSR (immediate)

[Jinjie Ruan via <qemu-devel@nongnu.org>]

Add ALLINT MSR (immediate) to decodetree, in which the CRm is 0b000x. The
EL0 check is necessary to ALLINT, and the EL1 check is necessary when
imm == 1. So implement it inline for EL2/3, or EL1 with imm==0. Avoid the
unconditional write to pc and use raise_exception_ra to unwind.

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
v7:
- Add Reviewed-by.
v6:
- Fix DISAS_TOO_MANY to DISAS_UPDATE_EXIT and add the comment.
v5:
- Drop the & 1 in trans_MSR_i_ALLINT().
- Simplify and merge msr_i_allint() and allint_check().
- Rename msr_i_allint() to msr_set_allint_el1().
v4:
- Fix the ALLINT MSR (immediate) decodetree implementation.
- Remove arm_is_el2_enabled() check in allint_check().
- Update env->allint to env->pstate.
- Only call allint_check() when imm == 1.
- Simplify the allint_check() to not pass "op" and extract.
- Implement it inline for EL2/3, or EL1 with imm==0.
- Pass (a->imm & 1) * PSTATE_ALLINT (i64) to simplfy the ALLINT set/clear.
v3:
- Remove EL0 check in allint_check().
- Add TALLINT check for EL1 in allint_check().
- Remove unnecessarily arm_rebuild_hflags() in msr_i_allint helper.
---
 target/arm/tcg/a64.decode      |  1 +
 target/arm/tcg/helper-a64.c    | 12 ++++++++++++
 target/arm/tcg/helper-a64.h    |  1 +
 target/arm/tcg/translate-a64.c | 19 +++++++++++++++++++
 4 files changed, 33 insertions(+)

diff --git a/target/arm/tcg/a64.decode b/target/arm/tcg/a64.decode
index 8a20dce3c8..0e7656fd15 100644
--- a/target/arm/tcg/a64.decode
+++ b/target/arm/tcg/a64.decode
@@ -207,6 +207,7 @@ MSR_i_DIT       1101 0101 0000 0 011 0100 .... 010 11111 @msr_i
 MSR_i_TCO       1101 0101 0000 0 011 0100 .... 100 11111 @msr_i
 MSR_i_DAIFSET   1101 0101 0000 0 011 0100 .... 110 11111 @msr_i
 MSR_i_DAIFCLEAR 1101 0101 0000 0 011 0100 .... 111 11111 @msr_i
+MSR_i_ALLINT    1101 0101 0000 0 001 0100 000 imm:1 000 11111
 MSR_i_SVCR      1101 0101 0000 0 011 0100 0 mask:2 imm:1 011 11111
 
 # MRS, MSR (register), SYS, SYSL. These are all essentially the
diff --git a/target/arm/tcg/helper-a64.c b/target/arm/tcg/helper-a64.c
index ebaa7f00df..7818537890 100644
--- a/target/arm/tcg/helper-a64.c
+++ b/target/arm/tcg/helper-a64.c
@@ -66,6 +66,18 @@ void HELPER(msr_i_spsel)(CPUARMState *env, uint32_t imm)
     update_spsel(env, imm);
 }
 
+void HELPER(msr_set_allint_el1)(CPUARMState *env)
+{
+    /* ALLINT update to PSTATE. */
+    if (arm_hcrx_el2_eff(env) & HCRX_TALLINT) {
+        raise_exception_ra(env, EXCP_UDEF,
+                           syn_aa64_sysregtrap(0, 1, 0, 4, 1, 0x1f, 0),
+                           exception_target_el(env), GETPC());
+    }
+
+    env->pstate |= PSTATE_ALLINT;
+}
+
 static void daif_check(CPUARMState *env, uint32_t op,
                        uint32_t imm, uintptr_t ra)
 {
diff --git a/target/arm/tcg/helper-a64.h b/target/arm/tcg/helper-a64.h
index 575a5dab7d..0518165399 100644
--- a/target/arm/tcg/helper-a64.h
+++ b/target/arm/tcg/helper-a64.h
@@ -22,6 +22,7 @@ DEF_HELPER_FLAGS_1(rbit64, TCG_CALL_NO_RWG_SE, i64, i64)
 DEF_HELPER_2(msr_i_spsel, void, env, i32)
 DEF_HELPER_2(msr_i_daifset, void, env, i32)
 DEF_HELPER_2(msr_i_daifclear, void, env, i32)
+DEF_HELPER_1(msr_set_allint_el1, void, env)
 DEF_HELPER_3(vfp_cmph_a64, i64, f16, f16, ptr)
 DEF_HELPER_3(vfp_cmpeh_a64, i64, f16, f16, ptr)
 DEF_HELPER_3(vfp_cmps_a64, i64, f32, f32, ptr)
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index 340265beb0..21758b290d 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -2036,6 +2036,25 @@ static bool trans_MSR_i_DAIFCLEAR(DisasContext *s, arg_i *a)
     return true;
 }
 
+static bool trans_MSR_i_ALLINT(DisasContext *s, arg_i *a)
+{
+    if (!dc_isar_feature(aa64_nmi, s) || s->current_el == 0) {
+        return false;
+    }
+
+    if (a->imm == 0) {
+        clear_pstate_bits(PSTATE_ALLINT);
+    } else if (s->current_el > 1) {
+        set_pstate_bits(PSTATE_ALLINT);
+    } else {
+        gen_helper_msr_set_allint_el1(tcg_env);
+    }
+
+    /* Exit the cpu loop to re-evaluate pending IRQs. */
+    s->base.is_jmp = DISAS_UPDATE_EXIT;
+    return true;
+}
+
 static bool trans_MSR_i_SVCR(DisasContext *s, arg_MSR_i_SVCR *a)
 {
     if (!dc_isar_feature(aa64_sme, s) || a->mask == 0) {
-- 
2.34.1