[PATCH 1/3] target/arm: Honor HCR_EL2.TID2 trapping requirements

[Marc Zyngier]

HCR_EL2.TID2 mandates that access from EL1 to CTR_EL0, CCSIDR_EL1,
CCSIDR2_EL1, CLIDR_EL1, CSSELR_EL1 are trapped to EL2, and QEMU
completely ignores it, making impossible for hypervisors to
virtualize the cache hierarchy.

Do the right thing by trapping to EL2 if HCR_EL2.TID2 is set.

Signed-off-by: Marc Zyngier <address@hidden>
---
 target/arm/helper.c | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 0bf8f53d4b..0b6887b100 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -1910,6 +1910,17 @@ static void scr_write(CPUARMState *env, const 
ARMCPRegInfo *ri, uint64_t value)
     raw_write(env, ri, value);
 }
 
+static CPAccessResult access_aa64_tid2(CPUARMState *env,
+                                       const ARMCPRegInfo *ri,
+                                       bool isread)
+{
+    if (arm_current_el(env) == 1 && (arm_hcr_el2_eff(env) & HCR_TID2)) {
+        return CP_ACCESS_TRAP_EL2;
+    }
+
+    return CP_ACCESS_OK;
+}
+
 static uint64_t ccsidr_read(CPUARMState *env, const ARMCPRegInfo *ri)
 {
     ARMCPU *cpu = env_archcpu(env);
@@ -2110,10 +2121,14 @@ static const ARMCPRegInfo v7_cp_reginfo[] = {
       .writefn = pmintenclr_write },
     { .name = "CCSIDR", .state = ARM_CP_STATE_BOTH,
       .opc0 = 3, .crn = 0, .crm = 0, .opc1 = 1, .opc2 = 0,
-      .access = PL1_R, .readfn = ccsidr_read, .type = ARM_CP_NO_RAW },
+      .access = PL1_R,
+      .accessfn = access_aa64_tid2,
+      .readfn = ccsidr_read, .type = ARM_CP_NO_RAW },
     { .name = "CSSELR", .state = ARM_CP_STATE_BOTH,
       .opc0 = 3, .crn = 0, .crm = 0, .opc1 = 2, .opc2 = 0,
-      .access = PL1_RW, .writefn = csselr_write, .resetvalue = 0,
+      .access = PL1_RW,
+      .accessfn = access_aa64_tid2,
+      .writefn = csselr_write, .resetvalue = 0,
       .bank_fieldoffsets = { offsetof(CPUARMState, cp15.csselr_s),
                              offsetof(CPUARMState, cp15.csselr_ns) } },
     /* Auxiliary ID register: this actually has an IMPDEF value but for now
@@ -5204,6 +5219,11 @@ static CPAccessResult ctr_el0_access(CPUARMState *env, 
const ARMCPRegInfo *ri,
     if (arm_current_el(env) == 0 && !(env->cp15.sctlr_el[1] & SCTLR_UCT)) {
         return CP_ACCESS_TRAP;
     }
+
+    if (arm_hcr_el2_eff(env) & HCR_TID2) {
+        return CP_ACCESS_TRAP_EL2;
+    }
+
     return CP_ACCESS_OK;
 }
 
@@ -6184,7 +6204,9 @@ void register_cp_regs_for_features(ARMCPU *cpu)
         ARMCPRegInfo clidr = {
             .name = "CLIDR", .state = ARM_CP_STATE_BOTH,
             .opc0 = 3, .crn = 0, .crm = 0, .opc1 = 1, .opc2 = 1,
-            .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = cpu->clidr
+            .access = PL1_R, .type = ARM_CP_CONST,
+            .accessfn = access_aa64_tid2,
+            .resetvalue = cpu->clidr
         };
         define_one_arm_cp_reg(cpu, &clidr);
         define_arm_cp_regs(cpu, v7_cp_reginfo);
-- 
2.20.1