Re: [PATCH v1 2/3] x86/domain: add helpers to simplify emulation flags management

[Jan Beulich <jbeulich@xxxxxxxx>]

On 01.04.2025 02:52, dmkhn@xxxxxxxxx wrote:
> From: Denis Mukhin <dmukhin@xxxxxxxx>
> 
> Introduce XEN_X86_EMU_BASELINE and XEN_X86_EMU_OPTIONAL to simplify
> d->arch.emulation_flags management in the code.

If the simplification is limited to ...

> --- a/tools/python/xen/lowlevel/xc/xc.c
> +++ b/tools/python/xen/lowlevel/xc/xc.c
> @@ -159,9 +159,7 @@ static PyObject *pyxc_domain_create(XcObject *self,
>  
>  #if defined (__i386) || defined(__x86_64__)
>      if ( config.flags & XEN_DOMCTL_CDF_hvm )
> -        config.arch.emulation_flags = XEN_X86_EMU_ALL &
> -                                      ~(XEN_X86_EMU_VPCI |
> -                                        XEN_X86_EMU_USE_PIRQ);
> +        config.arch.emulation_flags = XEN_X86_EMU_BASELINE;
>  #elif defined (__arm__) || defined(__aarch64__)
>      config.arch.gic_version = XEN_DOMCTL_CONFIG_GIC_NATIVE;
>  #else

... just this, I'm not convinced that's worth introducing yet two more items
into the namespace.

> --- a/xen/include/public/arch-x86/xen.h
> +++ b/xen/include/public/arch-x86/xen.h
> @@ -290,6 +290,13 @@ struct xen_arch_domainconfig {
>                                       XEN_X86_EMU_VGA | XEN_X86_EMU_IOMMU |   
> \
>                                       XEN_X86_EMU_PIT | XEN_X86_EMU_USE_PIRQ 
> |\
>                                       XEN_X86_EMU_VPCI)
> +
> +#define XEN_X86_EMU_OPTIONAL        (XEN_X86_EMU_VPCI | \
> +                                     XEN_X86_EMU_USE_PIRQ)
> +
> +#define XEN_X86_EMU_BASELINE        (XEN_X86_EMU_ALL & ~XEN_X86_EMU_OPTIONAL)
> +
> +    /* Hardware emulation flags. */
>      uint32_t emulation_flags;

The comment isn't quite accurate here (and hence perhaps also not in the
earlier patch): XEN_X86_EMU_USE_PIRQ isn't exactly about emulation of anything
hardware-ish.

Jan