Re: [PATCH v2 1/2] xen/domain: introduce non-x86 hardware emulation flags

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Fri, May 16, 2025 at 02:29:09AM +0000, dmkhn@xxxxxxxxx wrote:
> From: Denis Mukhin <dmukhin@xxxxxxxx>
> 
> Define per-architecture emulation_flags for configuring domain emulation
> features.
> 
> Print d->arch.emulation_flags from 'q' keyhandler for better traceability
> while debugging.
> 
> Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
> ---
> Changes since v1:
> - dropped comments
> ---
>  xen/arch/arm/include/asm/domain.h   | 1 +
>  xen/arch/ppc/include/asm/domain.h   | 1 +
>  xen/arch/riscv/include/asm/domain.h | 1 +
>  xen/common/keyhandler.c             | 1 +
>  4 files changed, 4 insertions(+)
> 
> diff --git a/xen/arch/arm/include/asm/domain.h 
> b/xen/arch/arm/include/asm/domain.h
> index a3487ca713..70e6e7d49b 100644
> --- a/xen/arch/arm/include/asm/domain.h
> +++ b/xen/arch/arm/include/asm/domain.h
> @@ -121,6 +121,7 @@ struct arch_domain
>      void *tee;
>  #endif
>  
> +    uint32_t emulation_flags;
>  }  __cacheline_aligned;
>  
>  struct arch_vcpu
> diff --git a/xen/arch/ppc/include/asm/domain.h 
> b/xen/arch/ppc/include/asm/domain.h
> index 3a447272c6..001116a0ab 100644
> --- a/xen/arch/ppc/include/asm/domain.h
> +++ b/xen/arch/ppc/include/asm/domain.h
> @@ -21,6 +21,7 @@ struct arch_vcpu {
>  
>  struct arch_domain {
>      struct hvm_domain hvm;
> +    uint32_t emulation_flags;
>  };
>  
>  #include <xen/sched.h>
> diff --git a/xen/arch/riscv/include/asm/domain.h 
> b/xen/arch/riscv/include/asm/domain.h
> index c3d965a559..7bc242da55 100644
> --- a/xen/arch/riscv/include/asm/domain.h
> +++ b/xen/arch/riscv/include/asm/domain.h
> @@ -18,6 +18,7 @@ struct arch_vcpu {
>  
>  struct arch_domain {
>      struct hvm_domain hvm;
> +    uint32_t emulation_flags;
>  };
>  
>  #include <xen/sched.h>
> diff --git a/xen/common/keyhandler.c b/xen/common/keyhandler.c
> index 0bb842ec00..73f5134b68 100644
> --- a/xen/common/keyhandler.c
> +++ b/xen/common/keyhandler.c
> @@ -306,6 +306,7 @@ static void cf_check dump_domains(unsigned char key)
>              if ( test_bit(i, &d->watchdog_inuse_map) )
>                  printk("    watchdog %d expires in %d seconds\n",
>                         i, (u32)((d->watchdog_timer[i].expires - NOW()) >> 
> 30));
> +        printk("    emulation_flags %#x\n", d->arch.emulation_flags);
>  
>          arch_dump_domain_info(d);

Hello,

I think it might be easier to print emulation_flags in
arch_dump_domain_info(), ideally it would be helpful if this could be
printed in a user friendly way apart from the raw dump:

printk("    emulation_flags:%s%s... (%#x)\n",
       !d->arch.emulation_flags ? " none" : "",
       has_vlapic(d) ? " lapic" : "", ...
       d->arch.emulation_flags);

Regards, Roger.