Re: [Qemu-devel] [PATCH] i386: Fix signedness of hyperv_spinlock_attempts

[Roman Kagan]

On Sat, Jun 15, 2019 at 05:05:05PM -0300, Eduardo Habkost wrote:
> The current default value for hv-spinlocks is 0xFFFFFFFF (meaning
> "never retry").  However, the value is stored as a signed
> integer, making the getter of the hv-spinlocks QOM property
> return -1 instead of 0xFFFFFFFF.
> 
> Fix this by changing the type of X86CPU::hyperv_spinlock_attempts
> to uint32_t.  This has no visible effect to guest operating
> systems, affecting just the behavior of the QOM getter.
> 
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
>  target/i386/cpu.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Roman Kagan <address@hidden>

That said, it's tempting to just nuke qdev_prop_spinlocks and make
hv-spinlocks a regular DEFINE_PROP_UINT32...

> 
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index 0732e059ec..8158d0de73 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -1372,7 +1372,7 @@ struct X86CPU {
>  
>      bool hyperv_vapic;
>      bool hyperv_relaxed_timing;
> -    int hyperv_spinlock_attempts;
> +    uint32_t hyperv_spinlock_attempts;
>      char *hyperv_vendor_id;
>      bool hyperv_time;
>      bool hyperv_crash;
> -- 
> 2.18.0.rc1.1.g3f1ff2140
>