On 9/16/25 10:40 PM, LIU Zhiwei wrote:
On 9/16/25 8:49 PM, Daniel Henrique Barboza wrote:
Hi!
On 9/9/25 10:25 AM, LIU Zhiwei wrote:
This patch set introduces support for the RISC-V Smmpt (Supervisor
Domain Access Protection) extension. It only includes two sub-extensions:
SMSDID and SMMPT.
This patch set implements the v0.3.4 version of Smmpt
(https://github.com/riscv/riscv-smmtt/releases/tag/v0.3.4).
As there are newer SMMPT specification versions, this patch set is
not intend for merging.
I'm not sure I understood. Do you mean this patch set isn't supposed to be
merged even after review?
Hi Daniel,
Thanks for the follow-up.
My primary goal is to have this feature merged eventually. I marked this version as
"not for merging" because I'm aware it's based on an older specification, and I
plan to update it to the latest one.
However, if the community finds this specific version (v0.3.4) useful for
current development, such as for CoVE or other ongoing work, I am open to
having it merged as is.
Having any implementation merged is better than no implementation. As long as
we document
it properly I don't see any problems. Let people use it for their own work and
we can
update it to a newer version as we go along.
Thanks,
Daniel
In any case, I will continue to work on an implementation aligned with the
newest specification. I would greatly appreciate any review comments or
feedback on the current approach.
Best regards,
Zhiwei
Daniel
The implementation is broken down into a series of logical steps:
Patch 1 adds the fundamental definitions for the Smmpt extension,
including
new CSRs (mmpt, msdcfg), their bit-field layouts, and the corresponding
CPU
configuration flags (ext_smmpt, ext_smsdid).
Patch 2 introduces the core logic for Memory Protection Table (MPT)
lookups.
It includes a new file, riscv_smmpt.c, which implements the multi-level
table walk to determine permissions for a given physical address.
Patch 3 integrates the MPT permission checks into the main MMU and TLB
handling pathways. This ensures that both page table walks and final
data accesses are subject to Smmpt protection rules.
Patch 4 adds support for the new fence instructions defined by the Smmpt
extension, specifically `mfence.spa` and `minval.spa`.
Patch 5 enables smmpt and smsdia extendion.
With this series, QEMU can now model systems that utilize the Smmpt
extension for enhanced memory security.
LIU Zhiwei (5):
target/riscv: Add basic definitions and CSRs for SMMPT
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: Enable SMMPT extension
target/riscv/cpu.c | 4 +
target/riscv/cpu.h | 9 +-
target/riscv/cpu_bits.h | 27 ++
target/riscv/cpu_cfg_fields.h.inc | 2 +
target/riscv/cpu_helper.c | 81 +++++-
target/riscv/csr.c | 83 ++++++
target/riscv/insn32.decode | 2 +
.../riscv/insn_trans/trans_privileged.c.inc | 30 ++
target/riscv/meson.build | 1 +
target/riscv/pmp.h | 3 +
target/riscv/riscv_smmpt.c | 273 ++++++++++++++++++
target/riscv/riscv_smmpt.h | 38 +++
12 files changed, 548 insertions(+), 5 deletions(-)
create mode 100644 target/riscv/riscv_smmpt.c
create mode 100644 target/riscv/riscv_smmpt.h
