On Thu, Sep 22, 2022, isaku.yamahata@intel.com wrote:
> From: Isaku Yamahata <isaku.yamahata@intel.com>
>
> Provide the name of the calling function to hardware_enable_nolock() and
> include it in the error message to provide additional information on
> exactly what path failed.
Changelog doesn't match the code.
> Opportunistically bump the pr_info() to pr_warn(), failure to enable
> virtualization support is warn-worthy as _something_ is wrong with the
> system.
>
> Suggested-by: Chao Gao <chao.gao@intel.com>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
> virt/kvm/kvm_main.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 4243a9541543..4f19c47aab1c 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -5006,7 +5006,8 @@ static void hardware_enable_nolock(void *junk)
> if (r) {
> cpumask_clear_cpu(cpu, cpus_hardware_enabled);
> atomic_inc(&hardware_enable_failed);
> - pr_info("kvm: enabling virtualization on CPU%d failed\n", cpu);
> + pr_warn("kvm: enabling virtualization on CPU%d failed during %pSb\n",
> + cpu, __builtin_return_address(0));
I vote to drop this patch. Trying to capture the caller is just a poor man's
version of WARN, and at the end of this series KVM should be at a point where KVM
can WARN when hardware enabling indicates a potentially fatal issue.
Specifically, kvm_arch_add_vm() shouldn't WARN since x86 can fail due a misbehaving
userspace. kvm_arch_online_cpu() on the other hand can and should WARN since
failure in that case means hardware enabling succeeded on other CPUs, and in the x86
case, that KVM is actively running VMs.