id = 2977
title = "QEMU SVM VMCB exit_code is uint32_t when AMD spec requires uint64_t"
state = "opened"
created_at = "2025-05-22T14:39:46.478Z"
closed_at = "n/a"
labels = []
url = "https://gitlab.com/qemu-project/qemu/-/issues/2977"
host-os = "Linux"
host-arch = "x86_64"
qemu-version = "QEMU emulator version 10.0.0"
guest-os = "Custom Type 1 Hypervisor"
guest-arch = "x86_64"
description = """QEMU's SVM implementation incorrectly uses a 32-bit parameter for the exit code in the `cpu_vmexit` function, despite the AMD SVM specification requiring a 64-bit exit code field in the VMCB (Virtual Machine Control Block).

I think the issue is in `target/i386/svm.c` in the `cpu_vmexit` function.

The `exit_code` parameter is declared as `uint32_t` but should be `uint64_t` according to the AMD SVM specification. This causes exit codes to be truncated to 32 bits, resulting in values like 0xffff_ffff instead of the expected 0xffff_ffff_ffff_ffff."""
reproduce = """"""
additional = """[this](https://stackoverflow.com/questions/79632531/qemu-svm-vmcb-exit-code-is-uint32-t-when-amd-spec-requires-uint64-t?noredirect=1#comment140448815_79632531) question I posted on stack overflow"""