Re: [PATCH v4 05/20] KVM: s390: vsie: Move pin/unpin_scb methods

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Moving `pin_scb()` and `unpin_scb()` above `pin_guest_page()` and `unpin_guest_page()` breaks the build due to implicit function declarations.
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--- Patch [5]: [PATCH v4 05/20] KVM: s390: vsie: Move pin/unpin_scb methods ---
commit 9ab8e79b084bfe3f666a241f273dcfef094a8a8b
Author: Christoph Schlameuss <[email protected]>

KVM: s390: vsie: Move pin/unpin_scb methods

This commit moves the pin_scb() and unpin_scb() functions higher up in
arch/s390/kvm/vsie.c in preparation for subsequent patches.

> diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
> index eea670530acbc..4b67bde0535fc 100644
> --- a/arch/s390/kvm/vsie.c
> +++ b/arch/s390/kvm/vsie.c
> @@ -660,6 +660,39 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
>  	return rc;
>  }
>  
> +/* unpin the scb provided by guest 2, marking it as dirty */
> +static void unpin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
> +		      gpa_t gpa)
> +{
> +	hpa_t hpa = virt_to_phys(vsie_page->scb_o);
> +
> +	if (hpa)
> +		unpin_guest_page(vcpu->kvm, gpa, hpa);

[Severity: Low]
Does moving this function up here cause a build failure?

It looks like unpin_guest_page() is defined later in the file. Calling it
here before it is declared or defined might result in an implicit function
declaration error during compilation.

> +	vsie_page->scb_o = NULL;
> +}
> +
> +/*
> + * Pin the scb at gpa provided by guest 2 at vsie_page->scb_o.
> + *
> + * Returns: - 0 if the scb was pinned.
> + *          - > 0 if control has to be given to guest 2
> + */
> +static int pin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
> +		   gpa_t gpa)
> +{
> +	hpa_t hpa;
> +	int rc;
> +
> +	rc = pin_guest_page(vcpu->kvm, gpa, &hpa);

[Severity: Low]
Similarly, does this call to pin_guest_page() also trigger an implicit
function declaration error, since it appears to be defined further down in
the file without a forward declaration?

> +	if (rc) {
> +		rc = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
> +		WARN_ON_ONCE(rc);
> +		return 1;
> +	}
> +	vsie_page->scb_o = phys_to_virt(hpa);
> +	return 0;
> +}

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=5