On 7/23/26 3:52 AM, Daniel Henrique Barboza wrote:
On 7/22/2026 12:11 AM, LIU Zhiwei wrote:
On 7/22/26 8:56 AM, Alistair wrote:
On Wed, 2026-07-15 at 22:50 +0800, LIU Zhiwei wrote:
This patch set introduces support for the RISC-V Smsdid and Smmpt
(Supervisor Domain Identifier and Memory Protection Table) extensions
v0.4.9(https://github.com/riscv/riscv-smmtt/releases/tag/v0.4.9).
Smmpt provides a hardware mechanism for fine-grained memory
protection,
checked after address translation, which is particularly useful for
supervisor-level sandboxing and security monitoring.
Hi Alistair,
Can you include a link to the upstream submitted patches to use this
functionality
Xiangyi is currently working on OpenSBI support for SMMPT, and we
already have an internal implementation in place. We plan to upstream
the OpenSBI support as soon as possible, and once that is done, I’ll
be able to include a link here.
Hi Daniel
Please be aware that Rahul already sent OpenSBI patches for smmpt and
smsdid:
[RFC PATCH 0/5] Add Smsdid and Smmpt supervisor domain protection
https://lists.infradead.org/pipermail/opensbi/2026-July/010235.html
In fact, as I said in another thread [1], Rahul also has a QEMU
implementation of his own.
His OpenSBI patches works with his QEMU changes:
https://github.com/pathakraul/qemu/tree/rpathak_smmpt_v1
Thank you very much for pointing this out and for coordinating between
us. I was not aware of Rahul's OpenSBI patches and QEMU implementation.
But seems like his OpenSBI patches does *not* work with this QEMU patches,
It seams probe_sdidlen in OpenSBI write a sdid to mmpt with bare mode.
According to the specification, in bare mode, "The remaining fields in
mmpt (SDID, PPN) must
be set to zeros.
but works
with his QEMU implementation. Seems like there might be things to
improve in both
implementations.
I asked him to not send his QEMU patches on top of yours because I'd
rather work in
collaboration on top of a single series, and I advise to not send
another OpenSBI support
for the same stuff in that mailing as well.
IMO you and Rahul should sync up in both OpenSBI and QEMU bits to
avoid effort duplication
on both sides.
I agree with your suggestion that it is better to avoid duplicated
effort and collaborate on a single direction for both the QEMU and
OpenSBI sides.
Since the SMMPT v0.4.9 specification is already close to stabilization,
and implementation work has already started in both OpenSBI and QEMU, I
believe we should be able to converge quickly through collaboration and
help move SMMPT upstream sooner.
Xiangyi and I will continue to review Rahul's OpenSBI patches to
understand the current differences and why they are not yet compatible
with our QEMU series. I will also reach out to Rahul directly so that we
can sync up and work toward a common implementation.
Thanks again for the pointers.
Best regards,
Zhiwei
Cheers,
Daniel
[1]
https://lore.kernel.org/qemu-devel/[email protected]/
Thanks,
Zhiwei
Alistair
The rfc patch set:
https://mail.gnu.org/archive/html/qemu-riscv/2025-09/msg00216.html
v6->v7:
The implementation is updated from the v0.3.4 specification to
v0.4.9. The main changes are:
1. Update the mmpt CSR number to 0x382 and msdcfg to 0x74E.
2. Update the mmpt register layout: the SDID and PPN field
positions
changed and the RV64 PPN is now 44 bits.
3. Rework the MPTE format: the N (NAPOT) bit now lives at bit 2,
the
non-leaf NAPOT form is removed, NAPOT leaf entries encode a
single
XWR tuple plus a G granularity field, and non-NAPOT leaf
entries
hold per-page XWR tuples.
4. Treat XWR=000 as "no access" and a non-leaf entry with N=1 as
a
fault.
5. Enforce the Smmpt64 root-table PPN alignment (low 3 bits
zero).
6. Rename the fence instructions mfence.spa/minval.spa to
mfence.pa/minval.pa.
7. Drop stale Reviewed-by tags on the substantially reworked
patches.
8. Introduce the configurable "smmpt-sdidlen" CPU property.
9. Add disassembly support for the Smmpt.
10. Add bare-metal M-mode system tests.
11. Rebase to master.
v5->v6:
1. Use explicitly bit fields extract instead of mpte_union_t.
2. Use the same exception behavior for MPT valiation as PMP
valiation.
3. Use PAGE_* instead of MPT_ACCESS_* as they have same value.
4. Use address_space_*_le instead of address_space_* for SMMPT.
5. Only print SMMPT address check log when SMMPT is enabled.
6. Add implied rule for SMMPT as it depends on SMSDID.
7. Rebase to master.
v4->v5:
1. Rebase to master.
v3->v4:
1. Add missing review tags.
v2->v3:
1. Fix build error in patch 2.
2. Rebase to master.
rfc->v2:
1. When ext_smmpt is false or BARE mode, make other fields in
mmpt
CSR zero.
2. Add patch 5 to fix smrnmi ISA string order.
3. Fix patch 6 smmpt and smsdid ISA string order.
4. Make smmpt and smsdid experiment extensions.
5. Add review tags.
LIU Zhiwei (11):
target/riscv: Add basic definitions and CSRs for SMMPT
target/riscv: Add smmpt-sdidlen property for the mmpt SDID field
target/riscv: Implement core SMMPT lookup logic
target/riscv: Integrate SMMPT checks into MMU and TLB fill
target/riscv: Implement SMMPT fence instructions
target/riscv: Fix smrnmi isa alphabetical order
target/riscv: Add disassembly for Smmpt instructions and CSRs
target/riscv: Enable SMMPT extension
target/riscv: Add system test for SMMPT extension
target/riscv: Add system tests for Smmpt52 and Smmpt64
target/riscv: Add system test for Smmpt34
disas/riscv.c | 9 +-
target/riscv/cpu.c | 60 +++-
target/riscv/cpu.h | 8 +
target/riscv/cpu_bits.h | 27 ++
target/riscv/cpu_cfg_fields.h.inc | 3 +
target/riscv/insn32.decode | 2 +
target/riscv/meson.build | 1 +
target/riscv/riscv_smmpt.c | 339
++++++++++++++++++
target/riscv/riscv_smmpt.h | 26 ++
target/riscv/tcg/cpu_helper.c | 119 +++++-
target/riscv/tcg/csr.c | 106 ++++++
.../tcg/insn_trans/trans_privileged.c.inc | 30 ++
target/riscv/tcg/pmp.h | 3 +
tests/tcg/riscv64/Makefile.softmmu-target | 12 +
tests/tcg/riscv64/smmpt-common.S | 256 +++++++++++++
tests/tcg/riscv64/test-smmpt.S | 85 +++++
tests/tcg/riscv64/test-smmpt34.S | 97 +++++
tests/tcg/riscv64/test-smmpt52.S | 91 +++++
tests/tcg/riscv64/test-smmpt64.S | 98 +++++
19 files changed, 1353 insertions(+), 19 deletions(-)
create mode 100644 target/riscv/riscv_smmpt.c
create mode 100644 target/riscv/riscv_smmpt.h
create mode 100644 tests/tcg/riscv64/smmpt-common.S
create mode 100644 tests/tcg/riscv64/test-smmpt.S
create mode 100644 tests/tcg/riscv64/test-smmpt34.S
create mode 100644 tests/tcg/riscv64/test-smmpt52.S
create mode 100644 tests/tcg/riscv64/test-smmpt64.S
base-commit: 499039798cdad7d86b787fec0eaf1da4151c0f05
