[PATCH RFC v2 0/3] riscv: add Svukte extension

[Max Hsu <max.hsu@sifive.com>]

RISC-V privileged spec will be added with Svukte extension [1]

Svukte introduce senvcfg.UKTE and hstatus.HUKTE bitfield.
which makes user-mode access to supervisor memory raise page faults
in constant time, mitigating attacks that attempt to discover the
supervisor software's address-space layout.

The following patches add
- dt-binding of Svukte ISA string
- CSR bit definition, ISA detection, senvcfg.UKTE enablement in kernel
- KVM ONE_REG support for Svukte extension

Changes in v2:
- rebase on riscv/for-next (riscv-for-linus-6.12-mw1)
- modify the description of dt-binding on Svukte ISA string
- Link to v1: https://lore.kernel.org/all/20240920-dev-maxh-svukte-rebase-v1-0-7864a88a62bd@sifive.com/

Link: https://github.com/riscv/riscv-isa-manual/pull/1564 [1]

Signed-off-by: Max Hsu <max.hsu@sifive.com>
---
Max Hsu (3):
      dt-bindings: riscv: Add Svukte entry
      riscv: Add Svukte extension support
      riscv: KVM: Add Svukte extension support for Guest/VM

 Documentation/devicetree/bindings/riscv/extensions.yaml | 9 +++++++++
 arch/riscv/include/asm/csr.h                            | 2 ++
 arch/riscv/include/asm/hwcap.h                          | 1 +
 arch/riscv/include/uapi/asm/kvm.h                       | 1 +
 arch/riscv/kernel/cpufeature.c                          | 4 ++++
 arch/riscv/kvm/vcpu_onereg.c                            | 1 +
 6 files changed, 18 insertions(+)
---
base-commit: b3f835cd7339919561866252a11831ead72e7073
change-id: 20240927-dev-maxh-svukte-rebase-2-5c4d296d1940

Best regards,
-- 
Max Hsu <max.hsu@sifive.com>