QEMU 2.13 Privileged ISA emulation updates

[Qemu-devel] [PATCH v8 19/35] RISC-V: Allow S-mode mxr access when priv ISA >= v1.10

Posted by Michael Clark 7 years, 9 months ago

The mstatus.MXR alias in sstatus should only be writable
by S-mode if the privileged ISA version >= v1.10. Also MXR
was masked in sstatus CSR read but not sstatus CSR writes.
Now we correctly mask sstatus.mxr in both read and write.

Cc: Sagar Karandikar <sagark@eecs.berkeley.edu>
Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Alistair Francis <Alistair.Francis@wdc.com>
Signed-off-by: Michael Clark <mjc@sifive.com>
---
 target/riscv/op_helper.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
index b81b9b6..88c263a 100644
--- a/target/riscv/op_helper.c
+++ b/target/riscv/op_helper.c
@@ -236,7 +236,10 @@ void csr_write_helper(CPURISCVState *env, target_ulong val_to_write,
         target_ulong ms = env->mstatus;
         target_ulong mask = SSTATUS_SIE | SSTATUS_SPIE | SSTATUS_UIE
             | SSTATUS_UPIE | SSTATUS_SPP | SSTATUS_FS | SSTATUS_XS
-            | SSTATUS_SUM | SSTATUS_MXR | SSTATUS_SD;
+            | SSTATUS_SUM | SSTATUS_SD;
+        if (env->priv_ver >= PRIV_VERSION_1_10_0) {
+            mask |= SSTATUS_MXR;
+        }
         ms = (ms & ~mask) | (val_to_write & mask);
         csr_write_helper(env, ms, CSR_MSTATUS);
         break;
@@ -439,7 +442,7 @@ target_ulong csr_read_helper(CPURISCVState *env, target_ulong csrno)
     case CSR_SSTATUS: {
         target_ulong mask = SSTATUS_SIE | SSTATUS_SPIE | SSTATUS_UIE
             | SSTATUS_UPIE | SSTATUS_SPP | SSTATUS_FS | SSTATUS_XS
-            | SSTATUS_SUM |  SSTATUS_SD;
+            | SSTATUS_SUM | SSTATUS_SD;
         if (env->priv_ver >= PRIV_VERSION_1_10_0) {
             mask |= SSTATUS_MXR;
         }
-- 
2.7.0

Re: [Qemu-devel] [PATCH v8 19/35] RISC-V: Allow S-mode mxr access when priv ISA >= v1.10

Posted by Alistair Francis 7 years, 9 months ago

On Wed, Apr 25, 2018 at 5:10 PM Michael Clark <mjc@sifive.com> wrote:

> The mstatus.MXR alias in sstatus should only be writable
> by S-mode if the privileged ISA version >= v1.10. Also MXR
> was masked in sstatus CSR read but not sstatus CSR writes.
> Now we correctly mask sstatus.mxr in both read and write.

> Cc: Sagar Karandikar <sagark@eecs.berkeley.edu>
> Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
> Cc: Palmer Dabbelt <palmer@sifive.com>
> Cc: Alistair Francis <Alistair.Francis@wdc.com>
> Signed-off-by: Michael Clark <mjc@sifive.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>   target/riscv/op_helper.c | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)

> diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
> index b81b9b6..88c263a 100644
> --- a/target/riscv/op_helper.c
> +++ b/target/riscv/op_helper.c
> @@ -236,7 +236,10 @@ void csr_write_helper(CPURISCVState *env,
target_ulong val_to_write,
>           target_ulong ms = env->mstatus;
>           target_ulong mask = SSTATUS_SIE | SSTATUS_SPIE | SSTATUS_UIE
>               | SSTATUS_UPIE | SSTATUS_SPP | SSTATUS_FS | SSTATUS_XS
> -            | SSTATUS_SUM | SSTATUS_MXR | SSTATUS_SD;
> +            | SSTATUS_SUM | SSTATUS_SD;
> +        if (env->priv_ver >= PRIV_VERSION_1_10_0) {
> +            mask |= SSTATUS_MXR;
> +        }
>           ms = (ms & ~mask) | (val_to_write & mask);
>           csr_write_helper(env, ms, CSR_MSTATUS);
>           break;
> @@ -439,7 +442,7 @@ target_ulong csr_read_helper(CPURISCVState *env,
target_ulong csrno)
>       case CSR_SSTATUS: {
>           target_ulong mask = SSTATUS_SIE | SSTATUS_SPIE | SSTATUS_UIE
>               | SSTATUS_UPIE | SSTATUS_SPP | SSTATUS_FS | SSTATUS_XS
> -            | SSTATUS_SUM |  SSTATUS_SD;
> +            | SSTATUS_SUM | SSTATUS_SD;
>           if (env->priv_ver >= PRIV_VERSION_1_10_0) {
>               mask |= SSTATUS_MXR;
>           }
> --
> 2.7.0