RISC-V: KVM: Widen G-stage fault address to gpa_t

fault_addr in gstage_page_fault() and the fault_addr parameter of
kvm_riscv_vcpu_mmio_load/store() are unsigned long.  On RV32 with
Sv32x4, guest physical addresses are 34 bits, so a 32-bit unsigned
long truncates bits 32/33 at two points:

  - reconstruction: fault_addr = (trap->htval << 2) | ... is evaluated
    in 32-bit arithmetic, dropping bits 32/33 before widening;
  - the MMIO handler call: even with the local widened, the handler's
    unsigned long parameter narrows it back to 32 bits, aliasing
    accesses above 4 GB into the low 4 GB.

Widen fault_addr 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().  The handlers' internal uses
(run->mmio.phys_addr is __u64, kvm_io_bus_read/write() take gpa_t) are
already 64-bit, so no further changes are needed.

Also in preparation for sharing a common struct kvm_page_fault across
architectures, where fault_addr is gpa_t.  No functional change on RV64.

Fixes: 9d05c1fee837 ("RISC-V: KVM: Implement stage2 page table programming")
Assisted-by: YuanSheng: deepseek-v4-pro
Co-developed-by: Quan Zhou <zhouquan@iscas.ac.cn>
Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
Signed-off-by: Bingyu Xian <shanbeeyoo@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20260729120733.829457-4-shanbeeyoo@gmail.com
Signed-off-by: Anup Patel <anup@brainfault.org>

0 files changed, 0 insertions, 0 deletions