[Qemu-devel] [PATCH v6 2/7] target-arm: Add CNTHCTL_EL2

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com>

Adds control for trapping selected timer and counter accesses to EL2.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
---
 target-arm/cpu.h    |  1 +
 target-arm/helper.c | 33 +++++++++++++++++++++++++++++++--
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index b1fa287..ea41052 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -358,6 +358,7 @@ typedef struct CPUARMState {
         };
         uint64_t c14_cntfrq; /* Counter Frequency register */
         uint64_t c14_cntkctl; /* Timer Control register */
+        uint32_t cnthctl_el2; /* Counter/Timer Hyp Control register */
         uint64_t cntvoff_el2; /* Counter Virtual Offset register */
         ARMGenericTimer c14_timer[NUM_GTIMERS];
         uint32_t c15_cpar; /* XScale Coprocessor Access Register */
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 26e8336..de9b246 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -1154,23 +1154,41 @@ static CPAccessResult gt_cntfrq_access(CPUARMState *env, const ARMCPRegInfo *ri)
 
 static CPAccessResult gt_counter_access(CPUARMState *env, int timeridx)
 {
+    unsigned int cur_el = arm_current_el(env);
+    bool secure = arm_is_secure(env);
+
     /* CNT[PV]CT: not visible from PL0 if ELO[PV]CTEN is zero */
-    if (arm_current_el(env) == 0 &&
+    if (cur_el == 0 &&
         !extract32(env->cp15.c14_cntkctl, timeridx, 1)) {
         return CP_ACCESS_TRAP;
     }
+
+    if (arm_feature(env, ARM_FEATURE_EL2) &&
+        timeridx == GTIMER_PHYS && !secure && cur_el < 2 &&
+        !extract32(env->cp15.cnthctl_el2, 0, 1)) {
+        return CP_ACCESS_TRAP_EL2;
+    }
     return CP_ACCESS_OK;
 }
 
 static CPAccessResult gt_timer_access(CPUARMState *env, int timeridx)
 {
+    unsigned int cur_el = arm_current_el(env);
+    bool secure = arm_is_secure(env);
+
     /* CNT[PV]_CVAL, CNT[PV]_CTL, CNT[PV]_TVAL: not visible from PL0 if
      * EL0[PV]TEN is zero.
      */
-    if (arm_current_el(env) == 0 &&
+    if (cur_el == 0 &&
         !extract32(env->cp15.c14_cntkctl, 9 - timeridx, 1)) {
         return CP_ACCESS_TRAP;
     }
+
+    if (arm_feature(env, ARM_FEATURE_EL2) &&
+        timeridx == GTIMER_PHYS && !secure && cur_el < 2 &&
+        !extract32(env->cp15.cnthctl_el2, 1, 1)) {
+        return CP_ACCESS_TRAP_EL2;
+    }
     return CP_ACCESS_OK;
 }
 
@@ -2631,6 +2649,9 @@ static const ARMCPRegInfo el3_no_el2_cp_reginfo[] = {
     { .name = "HTTBR", .cp = 15, .opc1 = 4, .crm = 2,
       .access = PL2_RW, .type = ARM_CP_64BIT | ARM_CP_CONST,
       .resetvalue = 0 },
+    { .name = "CNTHCTL_EL2", .state = ARM_CP_STATE_BOTH,
+      .opc0 = 3, .opc1 = 4, .crn = 14, .crm = 1, .opc2 = 0,
+      .access = PL2_RW, .type = ARM_CP_CONST, .resetvalue = 0 },
     { .name = "CNTVOFF_EL2", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 4, .crn = 14, .crm = 0, .opc2 = 3,
       .access = PL2_RW, .type = ARM_CP_CONST, .resetvalue = 0 },
@@ -2749,6 +2770,14 @@ static const ARMCPRegInfo el2_cp_reginfo[] = {
       .type = ARM_CP_NO_RAW, .access = PL2_W,
       .writefn = tlbi_aa64_vaa_write },
 #ifndef CONFIG_USER_ONLY
+    { .name = "CNTHCTL_EL2", .state = ARM_CP_STATE_BOTH,
+      .opc0 = 3, .opc1 = 4, .crn = 14, .crm = 1, .opc2 = 0,
+      /* ARMv7 requires bit 0 and 1 to reset to 1. ARMv8 defines the
+       * reset values as IMPDEF. We choose to reset to 3 to comply with
+       * both ARMv7 and ARMv8.
+       */
+      .access = PL2_RW, .resetvalue = 3,
+      .fieldoffset = offsetof(CPUARMState, cp15.cnthctl_el2) },
     { .name = "CNTVOFF_EL2", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 4, .crn = 14, .crm = 0, .opc2 = 3,
       .access = PL2_RW, .type = ARM_CP_IO, .resetvalue = 0,
-- 
1.9.1