From 4f4c385a8eedcace1f6c17b0d0ca41a53e0842b4 Mon Sep 17 00:00:00 2001
From: Richard Henderson <richard.henderson@linaro.org>
Date: Sat, 21 Mar 2020 13:50:32 -0400
Subject: [PATCH] target/arm: Update CNTVCT_EL0 for VHE

The virtual offset may be 0 depending on EL, E2H and TGE.

Backports commit 53d1f85608f83d645491eba6581d1f300dba2384 from qemu
---
 qemu/target/arm/helper.c | 40 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 37 insertions(+), 3 deletions(-)

diff --git a/qemu/target/arm/helper.c b/qemu/target/arm/helper.c
index b02c29c2..a99ffd41 100644
--- a/qemu/target/arm/helper.c
+++ b/qemu/target/arm/helper.c
@@ -2292,9 +2292,31 @@ static uint64_t gt_cnt_read(CPUARMState *env, const ARMCPRegInfo *ri)
     return gt_get_countervalue(env);
 }
 
+static uint64_t gt_virt_cnt_offset(CPUARMState *env)
+{
+    uint64_t hcr;
+
+    switch (arm_current_el(env)) {
+    case 2:
+        hcr = arm_hcr_el2_eff(env);
+        if (hcr & HCR_E2H) {
+            return 0;
+        }
+        break;
+    case 0:
+        hcr = arm_hcr_el2_eff(env);
+        if ((hcr & (HCR_E2H | HCR_TGE)) == (HCR_E2H | HCR_TGE)) {
+            return 0;
+        }
+        break;
+    }
+
+    return env->cp15.cntvoff_el2;
+}
+
 static uint64_t gt_virt_cnt_read(CPUARMState *env, const ARMCPRegInfo *ri)
 {
-    return gt_get_countervalue(env) - env->cp15.cntvoff_el2;
+    return gt_get_countervalue(env) - gt_virt_cnt_offset(env);
 }
 
 static void gt_cval_write(CPUARMState *env, const ARMCPRegInfo *ri,
@@ -2310,7 +2332,13 @@ static void gt_cval_write(CPUARMState *env, const ARMCPRegInfo *ri,
 static uint64_t gt_tval_read(CPUARMState *env, const ARMCPRegInfo *ri,
                              int timeridx)
 {
-    uint64_t offset = timeridx == GTIMER_VIRT ? env->cp15.cntvoff_el2 : 0;
+    uint64_t offset = 0;
+
+    switch (timeridx) {
+    case GTIMER_VIRT:
+        offset = gt_virt_cnt_offset(env);
+        break;
+    }
 
     return (uint32_t)(env->cp15.c14_timer[timeridx].cval -
                       (gt_get_countervalue(env) - offset));
@@ -2320,7 +2348,13 @@ static void gt_tval_write(CPUARMState *env, const ARMCPRegInfo *ri,
                           int timeridx,
                           uint64_t value)
 {
-    uint64_t offset = timeridx == GTIMER_VIRT ? env->cp15.cntvoff_el2 : 0;
+    uint64_t offset = 0;
+
+    switch (timeridx) {
+    case GTIMER_VIRT:
+        offset = gt_virt_cnt_offset(env);
+        break;
+    }
 
     // Unicorn: commented out
     //trace_arm_gt_tval_write(timeridx, value);