Re: [PATCH 09/12] KVM: PPC: Book3S HV nestedv2: Do not call H_COPY_TOFROM_GUEST

[Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org>]

Vaibhav Jain <vaibhav@linux.ibm.com> writes:

> From: Jordan Niethe <jniethe5@gmail.com>
>
> H_COPY_TOFROM_GUEST is part of the nestedv1 API and so should not be
> called by a nestedv2 host. Do not attempt to call it.
>

May be we should use
firmware_has_feature(FW_FEATURE_H_COPY_TOFROM_GUEST))?

the nestedv2 can end up using the above hcall if it is supported by the
hypervisor right? In its absence we will have to translate the guest ea
using xlate and then use kvm_guest_read to read location using the guest
real address right? That xlate will also involves multiple kvm_guest_read.


> Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
> ---
>  arch/powerpc/kvm/book3s_64_mmu_radix.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> index 916af6c153a5..4a1abb9f7c05 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> @@ -40,6 +40,9 @@ unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid,
>  	unsigned long quadrant, ret = n;
>  	bool is_load = !!to;
>  
> +	if (kvmhv_is_nestedv2())
> +		return H_UNSUPPORTED;
> +
>  	/* Can't access quadrants 1 or 2 in non-HV mode, call the HV to do it */
>  	if (kvmhv_on_pseries())
>  		return plpar_hcall_norets(H_COPY_TOFROM_GUEST, lpid, pid, eaddr,
> -- 
> 2.42.0