Re: [Xen-devel] [PATCH 2/3] x86 / hvm: add domain_relinquish_resources() method

[Jan Beulich <jbeulich@xxxxxxxx>]

On 21.01.2020 13:00, Paul Durrant wrote:
> There are two functions in hvm.c to deal with tear-down and a domain:
> hvm_domain_relinquish_resources() and hvm_domain_destroy(). However, only
> the latter has an associated method in 'hvm_funcs'. This patch adds
> a method for the former and stub definitions for SVM and VMX.

Why the stubs? Simply ...

> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -715,6 +715,8 @@ int hvm_domain_initialise(struct domain *d)
>  
>  void hvm_domain_relinquish_resources(struct domain *d)
>  {
> +    hvm_funcs.domain_relinquish_resources(d);

... stick a NULL check around this one. I also wonder whether, it
being entirely new, this wouldn't better use alternative call
patching right from the beginning. It's not the hottest path, but
avoiding indirect calls seems quite desirable, especially when
doing so is relatively cheap.

Jan

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