arm, kvm: enable running 32-bit Guest under ARM KVM64

1) Pass KVM_ARM_VCPU_EL1_32BIT to kvmArmVCpuInit
   when running 32-bit OS

2) Correctly map 64-bit registers to banked 32-bit ones

Change-Id: I1dec6427d6f5c3bba599ccdd804f1dfe80d3e670
Reviewed-on: https://gem5-review.googlesource.com/2261
Maintainer: Rahul Thakur <rjthakur@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

diff --git a/src/arch/arm/kvm/armv8_cpu.cc b/src/arch/arm/kvm/armv8_cpu.cc
index 08b9011233ab662b18fcc3fddf499b7dc69c3f56..67e2e465ea35bbe8a5954d5da96bb17dad1bf505 100644 (file)
--- a/src/arch/arm/kvm/armv8_cpu.cc
+++ b/src/arch/arm/kvm/armv8_cpu.cc
@@ -268,7 +268,13 @@ ArmV8KvmCPU::updateThreadContext()
     for (int i = 0; i < NUM_XREGS; ++i) {
         const auto value(getOneRegU64(kvmXReg(i)));
         DPRINTF(KvmContext, "  X%i := 0x%x\n", i, value);
-        tc->setIntReg(INTREG_X0 + i, value);
+        // KVM64 returns registers in 64-bit layout. If we are in aarch32
+        // mode, we need to map these to banked ARM32 registers.
+        if (inAArch64(tc)) {
+            tc->setIntReg(INTREG_X0 + i, value);
+        } else {
+            tc->setIntRegFlat(IntReg64Map[INTREG_X0 + i], value);
+        }
     }
 
     for (const auto &ri : intRegMap) {

diff --git a/src/arch/arm/kvm/base_cpu.cc b/src/arch/arm/kvm/base_cpu.cc
index e511fd6613fca5029853c744d6baf5a3d4e8f84a..e25112cae70e5a6a59f641b3815642d5e345580d 100644 (file)
--- a/src/arch/arm/kvm/base_cpu.cc
+++ b/src/arch/arm/kvm/base_cpu.cc
@@ -79,6 +79,9 @@ BaseArmKvmCPU::startup()
     memset(&target_config, 0, sizeof(target_config));
 
     vm.kvmArmPreferredTarget(target_config);
+    if (!((ArmSystem *)system)->highestELIs64()) {
+        target_config.features[0] |= (1 << KVM_ARM_VCPU_EL1_32BIT);
+    }
     kvmArmVCpuInit(target_config);
 }