[PATCH v3 0/3] RISC-V: KVM: G-stage fault path fix and cleanup

[Bingyu.Xian]

Three small changes to the RISC-V G-stage page fault path, sent as
separate patches per review feedback.

  1/3: Treat -EEXIST from kvm_riscv_gstage_map_page() as a quiet
       success, aligning RISC-V with x86 and arm64.  Real bug fix;
       Fixes: 9d05c1fee837, Cc: stable.

  2/3: vma_pageshift: short -> unsigned int.  No-functional-change
       type cleanup in preparation for sharing a common
       struct kvm_page_fault across architectures.

  3/3: Widen the G-stage fault address to gpa_t end to end -- the
       local in gstage_page_fault(), the (gpa_t) cast before the <<2
       shift, and the fault_addr parameters of kvm_riscv_vcpu_mmio_load/
       store().  This completes the RV32 34-bit GPA fix that v2 only
       half-addressed: v2 widened the local and cast the shift, but the
       address was still narrowed to 32 bits at the MMIO handler call
       (unsigned long parameter), aliasing accesses above 4 GB into the
       low 4 GB.  The handlers' internal uses (run->mmio.phys_addr is
       __u64, kvm_io_bus_read/write() take gpa_t) are already 64-bit.
       Also in preparation for sharing a common struct kvm_page_fault.
       No functional change on RV64.  Not Cc'd to stable: RV32 KVM is
       unsupported and this is untested at runtime.

Changes since v2 [1]:
  - Split into separate patches per feedback.
  - Completed the fault_addr widening v2 left half-done: widened the
    kvm_riscv_vcpu_mmio_load/store() fault_addr parameters to gpa_t so
    the 34-bit address is not truncated at the MMIO handler call.

The KVM_MEM_USERFAULT port that motivated this cleanup will follow as a
separate RFC.

[1] https://lore.kernel.org/kvm/20260729075230.743030-1-shanbeeyoo@gmail.com/

Bingyu.Xian (3):
  RISC-V: KVM: Treat -EEXIST from G-stage map as success
  RISC-V: KVM: Use unsigned int for vma_pageshift
  RISC-V: KVM: Widen G-stage fault address to gpa_t

 arch/riscv/include/asm/kvm_vcpu_insn.h | 4 ++--
 arch/riscv/kvm/mmu.c                   | 8 +++++---
 arch/riscv/kvm/vcpu_exit.c             | 5 +++--
 arch/riscv/kvm/vcpu_insn.c             | 4 ++--
 4 files changed, 12 insertions(+), 9 deletions(-)

-- 
2.54.0