Re: [PATCH v5 6/7] KVM: x86: Combine .gmem_prepare()+.gmem_invalidate() into .gmem_convert()

[Ackerley Tng]

Sean Christopherson <seanjc@xxxxxxxxxx> writes:

> +int sev_gmem_convert(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
> +		     kvm_pfn_t nr_pages, int order, bool to_private)
> +{
> +	if (to_private) {
> +		if (WARN_ON_ONCE(!kvm || gfn >> (kvm_host.maxphyaddr - PAGE_SHIFT)))

Omg, maxphyaddr is actually the number of bits in an address and not an
address!

Thanks for explaining on v4.

> +			return -EIO;
> +
> +		return sev_gmem_make_private(kvm, gfn, pfn, nr_pages, order);
> +	}
> +
> +	sev_gmem_make_shared(pfn, nr_pages);
> +	return 0;
> +}
> +
>
> [...snip...]
>

>  #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_RECLAIM
>  void kvm_arch_gmem_reclaim(kvm_pfn_t pfn, kvm_pfn_t nr_pages, int max_order)
>  {
> -	kvm_x86_call(gmem_invalidate)(pfn, pfn + nr_pages);
> +	WARN_ON_ONCE(kvm_x86_call(gmem_convert)(NULL, -1ull, pfn, nr_pages, max_order, false));

This setup means later pKVM would have to define a .gmem_convert but
actually only use it for reclaim, which seems kind of an odd
definition. (We can fix this later.)

Reviewed-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>

>  }
>  #endif
>
> --
> 2.55.0.141.g00534a21ce-goog