target/riscv: Fix update of hstatus.GVA in riscv_cpu_do_interrupt

The hstatus.GVA bit was not set if the faulting guest virtual address
was zero.

Signed-off-by: Georg Kotheimer <georg.kotheimer@kernkonzept.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20201013173054.451135-1-georg.kotheimer@kernkonzept.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu_helper.c

@@ -852,6 +852,7 @@ void riscv_cpu_do_interrupt(CPUState *cs)
     bool async = !!(cs->exception_index & RISCV_EXCP_INT_FLAG);
     target_ulong cause = cs->exception_index & RISCV_EXCP_INT_MASK;
     target_ulong deleg = async ? env->mideleg : env->medeleg;
+    bool write_tval = false;
     target_ulong tval = 0;
     target_ulong htval = 0;
     target_ulong mtval2 = 0;
@@ -873,6 +874,7 @@ void riscv_cpu_do_interrupt(CPUState *cs)
         case RISCV_EXCP_INST_PAGE_FAULT:
         case RISCV_EXCP_LOAD_PAGE_FAULT:
         case RISCV_EXCP_STORE_PAGE_FAULT:
+            write_tval  = true;
             tval = env->badaddr;
             break;
         default:
@@ -910,7 +912,7 @@ void riscv_cpu_do_interrupt(CPUState *cs)
             target_ulong hdeleg = async ? env->hideleg : env->hedeleg;
 
             if ((riscv_cpu_virt_enabled(env) ||
-                 riscv_cpu_two_stage_lookup(env)) && tval) {
+                 riscv_cpu_two_stage_lookup(env)) && write_tval) {
                 /*
                  * If we are writing a guest virtual address to stval, set
                  * this to 1. If we are trapping to VS we will set this to 0