[PATCH v5 4/6] target-arm: kvm64 sync FP register state

["Alex Bennée" <alex.bennee@linaro.org>]

For migration to work we need to sync all of the register state. This is
especially noticeable when GCC starts using FP registers as spill
registers even with integer programs.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

---

v4:
  - fixed merge conflicts
  - rm superfluous reg.id++
v5:
  - use interim float128 to deal with endianess
  - correctly map into vfp.regs[]
  - fix spacing around []s

diff --git a/target-arm/kvm64.c b/target-arm/kvm64.c
index fed03f2..857e970 100644
--- a/target-arm/kvm64.c
+++ b/target-arm/kvm64.c
@@ -126,9 +126,16 @@ bool kvm_arm_reg_syncs_via_cpreg_list(uint64_t regidx)
 #define AARCH64_CORE_REG(x)   (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \
                  KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(x))
 
+#define AARCH64_SIMD_CORE_REG(x)   (KVM_REG_ARM64 | KVM_REG_SIZE_U128 | \
+                 KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(x))
+
+#define AARCH64_SIMD_CTRL_REG(x)   (KVM_REG_ARM64 | KVM_REG_SIZE_U32 | \
+                 KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(x))
+
 int kvm_arch_put_registers(CPUState *cs, int level)
 {
     struct kvm_one_reg reg;
+    uint32_t fpr;
     uint64_t val;
     int i;
     int ret;
@@ -207,15 +214,42 @@ int kvm_arch_put_registers(CPUState *cs, int level)
         }
     }
 
+    /* Advanced SIMD and FP registers
+     * We map Qn = regs[2n+1]:regs[2n]
+     */
+    for (i = 0; i < 32; i++) {
+        int rd = i << 1;
+        float128 fp_val = make_float128(env->vfp.regs[rd + 1],
+                                        env->vfp.regs[rd]);
+        reg.id = AARCH64_SIMD_CORE_REG(fp_regs.vregs[i]);
+        reg.addr = (uintptr_t)(&fp_val);
+        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
+        if (ret) {
+            return ret;
+        }
+    }
+
+    reg.addr = (uintptr_t)(&fpr);
+    fpr = vfp_get_fpsr(env);
+    reg.id = AARCH64_SIMD_CTRL_REG(fp_regs.fpsr);
+    ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
+    if (ret) {
+        return ret;
+    }
+
+    fpr = vfp_get_fpcr(env);
+    reg.id = AARCH64_SIMD_CTRL_REG(fp_regs.fpcr);
+    ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
+    if (ret) {
+        return ret;
+    }
+
     if (!write_list_to_kvmstate(cpu)) {
         return EINVAL;
     }
 
     kvm_arm_sync_mpstate_to_kvm(cpu);
 
-    /* TODO:
-     * FP state
-     */
     return ret;
 }
 
@@ -223,6 +257,7 @@ int kvm_arch_get_registers(CPUState *cs)
 {
     struct kvm_one_reg reg;
     uint64_t val;
+    uint32_t fpr;
     int i;
     int ret;
 
@@ -304,6 +339,38 @@ int kvm_arch_get_registers(CPUState *cs)
         }
     }
 
+    /* Advanced SIMD and FP registers
+     * We map Qn = regs[2n+1]:regs[2n]
+     */
+    for (i = 0; i < 32; i++) {
+        float128 fp_val;
+        reg.id = AARCH64_SIMD_CORE_REG(fp_regs.vregs[i]);
+        reg.addr = (uintptr_t)(&fp_val);
+        ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+        if (ret) {
+            return ret;
+        } else {
+            int rd = i << 1;
+            env->vfp.regs[rd + 1] = fp_val.high;
+            env->vfp.regs[rd] = fp_val.low;
+        }
+    }
+
+    reg.addr = (uintptr_t)(&fpr);
+    reg.id = AARCH64_SIMD_CTRL_REG(fp_regs.fpsr);
+    ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+    if (ret) {
+        return ret;
+    }
+    vfp_set_fpsr(env, fpr);
+
+    reg.id = AARCH64_SIMD_CTRL_REG(fp_regs.fpcr);
+    ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+    if (ret) {
+        return ret;
+    }
+    vfp_set_fpcr(env, fpr);
+
     if (!write_kvmstate_to_list(cpu)) {
         return EINVAL;
     }
-- 
2.3.2