[PATCH v2 2/5] target/arm: Honor HCR_EL2.TID1 trapping requirements

[Marc Zyngier <maz@kernel.org>]

HCR_EL2.TID1 mandates that access from EL1 to REVIDR_EL1, AIDR_EL1
(and their 32bit equivalents) as well as TCMTR, TLBTR are trapped
to EL2. QEMU ignores it, making it harder for a hypervisor to
virtualize the HW (though to be fair, no known hypervisor actually
cares).

Do the right thing by trapping to EL2 if HCR_EL2.TID1 is set.

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 target/arm/helper.c | 36 ++++++++++++++++++++++++++++++++----
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 1e546096b8..93ecab27c0 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -1973,6 +1973,26 @@ static uint64_t isr_read(CPUARMState *env, const ARMCPRegInfo *ri)
     return ret;
 }
 
+static CPAccessResult access_aa64_tid1(CPUARMState *env, const ARMCPRegInfo *ri,
+                                       bool isread)
+{
+    if (arm_current_el(env) == 1 && (arm_hcr_el2_eff(env) & HCR_TID1)) {
+        return CP_ACCESS_TRAP_EL2;
+    }
+
+    return CP_ACCESS_OK;
+}
+
+static CPAccessResult access_aa32_tid1(CPUARMState *env, const ARMCPRegInfo *ri,
+                                       bool isread)
+{
+    if (arm_feature(env, ARM_FEATURE_V8)) {
+        return access_aa64_tid1(env, ri, isread);
+    }
+
+    return CP_ACCESS_OK;
+}
+
 static const ARMCPRegInfo v7_cp_reginfo[] = {
     /* the old v6 WFI, UNPREDICTABLE in v7 but we choose to NOP */
     { .name = "NOP", .cp = 15, .crn = 7, .crm = 0, .opc1 = 0, .opc2 = 4,
@@ -2136,7 +2156,9 @@ static const ARMCPRegInfo v7_cp_reginfo[] = {
      */
     { .name = "AIDR", .state = ARM_CP_STATE_BOTH,
       .opc0 = 3, .opc1 = 1, .crn = 0, .crm = 0, .opc2 = 7,
-      .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = 0 },
+      .access = PL1_R, .type = ARM_CP_CONST,
+      .accessfn = access_aa64_tid1,
+      .resetvalue = 0 },
     /* Auxiliary fault status registers: these also are IMPDEF, and we
      * choose to RAZ/WI for all cores.
      */
@@ -6732,7 +6754,9 @@ void register_cp_regs_for_features(ARMCPU *cpu)
               .access = PL1_R, .resetvalue = cpu->midr },
             { .name = "REVIDR_EL1", .state = ARM_CP_STATE_BOTH,
               .opc0 = 3, .opc1 = 0, .crn = 0, .crm = 0, .opc2 = 6,
-              .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = cpu->revidr },
+              .access = PL1_R,
+              .accessfn = access_aa64_tid1,
+              .type = ARM_CP_CONST, .resetvalue = cpu->revidr },
             REGINFO_SENTINEL
         };
         ARMCPRegInfo id_cp_reginfo[] = {
@@ -6748,14 +6772,18 @@ void register_cp_regs_for_features(ARMCPU *cpu)
             /* TCMTR and TLBTR exist in v8 but have no 64-bit versions */
             { .name = "TCMTR",
               .cp = 15, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 2,
-              .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = 0 },
+              .access = PL1_R,
+              .accessfn = access_aa32_tid1,
+              .type = ARM_CP_CONST, .resetvalue = 0 },
             REGINFO_SENTINEL
         };
         /* TLBTR is specific to VMSA */
         ARMCPRegInfo id_tlbtr_reginfo = {
               .name = "TLBTR",
               .cp = 15, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 3,
-              .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = 0,
+              .access = PL1_R,
+              .accessfn = access_aa32_tid1,
+              .type = ARM_CP_CONST, .resetvalue = 0,
         };
         /* MPUIR is specific to PMSA V6+ */
         ARMCPRegInfo id_mpuir_reginfo = {
-- 
2.20.1