qemu-user fails to run 32-bit x86 binaries on hosts with a page size > 4KB

Host environment

• Operating system: ALT Linux sisyphus
• OS/kernel version: Linux 6.7.3 loongarch64
• Architecture: LoongArch, ARM64
• QEMU flavor: qemu-i386 (Linux userspace emulation)
• QEMU version: 8.2.0
• QEMU command line: qemu-i386

Emulated/Virtualized environment

• Operating system: Linux userspace emulation
• OS/kernel version: not applicable
• Architecture: 32-bit x86

Description of problem

qemu-i386 refuses to run 32-bit x86 binaries on hosts with a page size > 4KB (such as LoongArch, ppc64le, arm64 with 3 level page tables).

Steps to reproduce

1. Compile x86 binary which makes a single exit(0) syscall:

cat > exit0.S << EOF
#include <sys/syscall.h>
.text
.global _start
 _start:
   movl $__NR_exit, %eax
   movl $0, %ebx
   int $0x80
EOF
i586-linux-gnu-gcc -nostdlib -static -no-pie -o exit0 exit0.S

Alternatively one might compile it on a x86 host:

gcc -m32 -nostdlib -static -no-pie -o exit0 exit0.S

and transfer the exit0 binary to ppc64/LoongArch/arm64 system

2. Run the exit0 binary with qemu-i386

qemu-i386-static ./exit0

Expected result

exit0 binary runs (and exits with 0 status)

Actual result

 qemu-i386-static: ../linux-user/elfload.c:3019: pgb_dynamic: Assertion `QEMU_IS_ALIGNED(guest_loaddr, align)' failed.

Additional information

.text segment of (32-bit) x86 binaries is typically aligned at 4KB:

Program Headers:
  Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
  LOAD           0x000000 0x08048000 0x08048000 0x00100 0x00100 R   0x1000
  LOAD           0x001000 0x08049000 0x08049000 0x0000c 0x0000c R E 0x1000
  NOTE           0x0000b4 0x080480b4 0x080480b4 0x0004c 0x0004c R   0x4
  GNU_PROPERTY   0x0000d8 0x080480d8 0x080480d8 0x00028 0x00028 R   0x4

Thus on a host with a page size being 64 KB (ppc64, arm64 with 3 level page tables) or 16 KB (LoongArch) alignment requirements in pbg_dynamic can not be satisfied.