target/riscv/csr.c: do not allow mstatus MPV/GVA writes

The priv spec states the following about mstatus.MPV:

"The MPV bit (Machine Previous Virtualization Mode) is written by the
implementation whenever a trap is taken into M-mode."

And, about mstatus.GVA:

"Field GVA (Guest Virtual Address) is written by the implementation
whenever a trap is taken into M-mode."

Both are written during riscv_cpu_do_interrupt().  They're not supposed
to be written by userspace.  As far as write_mstatus goes these fields
are read only.  The same applies for mstatush.MPV/mstatush.GVA.

Fixes: 03dd405dd5 ("target/riscv: Support MSTATUS.MPV/GVA only when RVH is enabled")
Signed-off-by: Daniel Henrique Barboza <daniel.barboza@oss.qualcomm.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20260514194537.2416243-2-daniel.barboza@oss.qualcomm.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
(cherry picked from commit 18645f19578955ec5ff2c40cd2c8753d6bc460c2)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

1 files changed, 1 insertions, 4 deletions

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index a62b16feae..5e1b840087 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -2014,9 +2014,6 @@ static RISCVException write_mstatus(CPURISCVState *env, int csrno,
     }
 
     if (xl != MXL_RV32 || env->debugger) {
-        if (riscv_has_ext(env, RVH)) {
-            mask |= MSTATUS_MPV | MSTATUS_GVA;
-        }
         if ((val & MSTATUS64_UXL) != 0) {
             mask |= MSTATUS64_UXL;
         }
@@ -2053,7 +2050,7 @@ static RISCVException write_mstatush(CPURISCVState *env, int csrno,
                                      target_ulong val)
 {
     uint64_t valh = (uint64_t)val << 32;
-    uint64_t mask = riscv_has_ext(env, RVH) ? MSTATUS_MPV | MSTATUS_GVA : 0;
+    uint64_t mask = 0;
 
     if (riscv_cpu_cfg(env)->ext_smdbltrp) {
         mask |= MSTATUS_MDT;