Re: [PATCH v2 03/13] KVM: selftests: Fudge around an apparent gcc bug in arm64's PMU test

Sean Christopherson
2024-09-30T21:57:02Z

On Wed, Sep 11, 2024, Sean Christopherson wrote:
> Use u64_replace_bits() instead of u64p_replace_bits() to set PMCR.N in
> arm64's vPMU counter access test to fudge around what appears to be a gcc
> bug. With the recent change to have vcpu_get_reg() return a value in lieu
> of an out-param, some versions of gcc completely ignore the operation
> performed by set_pmcr_n(), i.e. ignore the output param.

Filed a gcc bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116912

I'll report back if anything interesting comes out of that bug.