Re: [PATCH V2 1/2] KVM: arm/arm64: Enable KVM_CAP_NR_MEMSLOTS on arm/arm64

[Christoffer Dall <cdall@linaro.org>]

On Wed, Feb 08, 2017 at 12:45:40PM +0530, linucherian@gmail.com wrote:
> From: Linu Cherian <linu.cherian@cavium.com>
> 
> Return KVM_USER_MEM_SLOTS for userspace capability query on
> NR_MEMSLOTS.

This feature seems to be undocumented (I cannot find it in
Documentation/virtual/kvm/api.txt).

Can we add documentation for it?

What does user space do currently without this capability?  Does it just
rely on some default?

Thanks,
-Christoffer

> 
> Signed-off-by: Linu Cherian <linu.cherian@cavium.com>
> ---
>  arch/arm/kvm/arm.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index 9d74464..b64b47f 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -221,6 +221,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
>  	case KVM_CAP_MAX_VCPUS:
>  		r = KVM_MAX_VCPUS;
>  		break;
> +	case KVM_CAP_NR_MEMSLOTS:
> +		r = KVM_USER_MEM_SLOTS;
> +		break;
>  	case KVM_CAP_MSI_DEVID:
>  		if (!kvm)
>  			r = -EINVAL;
> -- 
> 1.9.1
>