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| author | Christian Krinitsin <mail@krinitsin.com> | 2025-05-30 16:52:07 +0200 |
|---|---|---|
| committer | Christian Krinitsin <mail@krinitsin.com> | 2025-05-30 16:52:17 +0200 |
| commit | 9260319e7411ff8281700a532caa436f40120ec4 (patch) | |
| tree | 2f6bfe5f3458dd49d328d3a9eb508595450adec0 /gitlab/issues_text/target_riscv/host_missing/accel_missing/1793 | |
| parent | 225caa38269323af1bfc2daadff5ec8bd930747f (diff) | |
| download | qemu-analysis-9260319e7411ff8281700a532caa436f40120ec4.tar.gz qemu-analysis-9260319e7411ff8281700a532caa436f40120ec4.zip | |
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Diffstat (limited to 'gitlab/issues_text/target_riscv/host_missing/accel_missing/1793')
| -rw-r--r-- | gitlab/issues_text/target_riscv/host_missing/accel_missing/1793 | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/gitlab/issues_text/target_riscv/host_missing/accel_missing/1793 b/gitlab/issues_text/target_riscv/host_missing/accel_missing/1793 new file mode 100644 index 000000000..ff880bfa1 --- /dev/null +++ b/gitlab/issues_text/target_riscv/host_missing/accel_missing/1793 @@ -0,0 +1,35 @@ +getauxval(AT_HWCAP) returns different value under qemu-system-riscv64 and qemu-riscv64 +Description of problem: +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 +``` +Steps to 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 information: + |