id = 1793
title = "getauxval(AT_HWCAP) returns different value under qemu-system-riscv64 and qemu-riscv64"
state = "closed"
created_at = "2023-07-27T00:12:49.466Z"
closed_at = "2023-08-07T01:16:42.433Z"
labels = ["Closed::Fixed", "linux-user", "target: riscv"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/1793"
host-os = "Gentoo Linux"
host-arch = "x86_64"
qemu-version = "qemu-riscv64 version 8.0.3"
guest-os = "Gentoo Linux"
guest-arch = "riscv64"
description = """I have a test program that checks for the presence of the RISC-V Vector extension (RVV) via getauxval().

```c
#include <sys/auxv.h>
#include <stdio.h>

#define ISA_V_HWCAP (1 << ('v' - 'a'))

void main() {
  unsigned long hw_cap = getauxval(AT_HWCAP);
  printf("RVV %s\\n", hw_cap & ISA_V_HWCAP ? "detected" : "not found");
}
```

When run inside `qemu-system-riscv64` with a 6.5-rc3 kernel where `CONFIG_RISCV_ISA_V=y` and `CONFIG_RISCV_ISA_V_DEFAULT_ENABLE=y` it correctly shows:

```
$ ./hwcap
RVV detected
```

However when executed with `qemu-riscv64` it does not return the V bit set:

```
$ qemu-riscv64 hwcap
RVV not found
```"""
reproduce = """1. Boot 6.5-rc3 kernel with `CONFIG_RISCV_ISA_V=y` and `CONFIG_RISCV_ISA_V_DEFAULT_ENABLE=y`
2. In guest run test program hwcap (source above)
3. On host run `qemu-riscv64 hwcap`"""
additional = """"""