Re: [PATCH v1 4/4] KVM: PPC: Book3S HV: migrate hot plugged memory

[Laurent Dufour <ldufour@linux.ibm.com>]

Le 31/05/2020 à 04:27, Ram Pai a écrit :
> From: Laurent Dufour <ldufour@linux.ibm.com>
> 
> When a memory slot is hot plugged to a SVM, GFNs associated with that
> memory slot automatically default to secure GFN. Hence migrate the
> PFNs associated with these GFNs to device-PFNs.
> 
> uv_migrate_mem_slot() is called to achieve that. It will not call
> UV_PAGE_IN since this request is ignored by the Ultravisor.
> NOTE: Ultravisor does not trust any page content provided by
> the Hypervisor, ones the VM turns secure.
> 
> Cc: Paul Mackerras <paulus@ozlabs.org>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Bharata B Rao <bharata@linux.ibm.com>
> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
> Cc: Laurent Dufour <ldufour@linux.ibm.com>
> Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
> Cc: David Gibson <david@gibson.dropbear.id.au>
> Cc: Claudio Carvalho <cclaudio@linux.ibm.com>
> Cc: kvm-ppc@vger.kernel.org
> Cc: linuxppc-dev@lists.ozlabs.org
> Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> 	(fixed merge conflicts. Modified the commit message)
> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
> ---
>   arch/powerpc/include/asm/kvm_book3s_uvmem.h |  4 ++++
>   arch/powerpc/kvm/book3s_hv.c                | 11 +++++++----
>   arch/powerpc/kvm/book3s_hv_uvmem.c          |  3 +--
>   3 files changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/kvm_book3s_uvmem.h b/arch/powerpc/include/asm/kvm_book3s_uvmem.h
> index f0c5708..2ec2e5afb 100644
> --- a/arch/powerpc/include/asm/kvm_book3s_uvmem.h
> +++ b/arch/powerpc/include/asm/kvm_book3s_uvmem.h
> @@ -23,6 +23,7 @@ unsigned long kvmppc_h_svm_page_out(struct kvm *kvm,
>   void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free,
>   			     struct kvm *kvm, bool skip_page_out,
>   			     bool purge_gfn);
> +int uv_migrate_mem_slot(struct kvm *kvm, const struct kvm_memory_slot *memslot);
>   #else
>   static inline int kvmppc_uvmem_init(void)
>   {
> @@ -78,5 +79,8 @@ static inline int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn)
>   kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free,
>   			struct kvm *kvm, bool skip_page_out,
>   			bool purge_gfn) { }
> +
> +static int uv_migrate_mem_slot(struct kvm *kvm,
> +		const struct kvm_memory_slot *memslot);

That line was not part of the patch I sent to you!


>   #endif /* CONFIG_PPC_UV */
>   #endif /* __ASM_KVM_BOOK3S_UVMEM_H__ */
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 4c62bfe..604d062 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -4516,13 +4516,16 @@ static void kvmppc_core_commit_memory_region_hv(struct kvm *kvm,
>   	case KVM_MR_CREATE:
>   		if (kvmppc_uvmem_slot_init(kvm, new))
>   			return;
> -		uv_register_mem_slot(kvm->arch.lpid,
> -				     new->base_gfn << PAGE_SHIFT,
> -				     new->npages * PAGE_SIZE,
> -				     0, new->id);
> +		if (uv_register_mem_slot(kvm->arch.lpid,
> +					 new->base_gfn << PAGE_SHIFT,
> +					 new->npages * PAGE_SIZE,
> +					 0, new->id))
> +			return;
> +		uv_migrate_mem_slot(kvm, new);
>   		break;
>   	case KVM_MR_DELETE:
>   		uv_unregister_mem_slot(kvm->arch.lpid, old->id);
> +		kvmppc_uvmem_drop_pages(old, kvm, true, true);

Again that line has been changed from the patch I sent to you. The last 'true' 
argument has nothing to do here.

Is that series really building?

>   		kvmppc_uvmem_slot_free(kvm, old);
>   		break;
>   	default:
> diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
> index 36dda1d..1fa5f2a 100644
> --- a/arch/powerpc/kvm/book3s_hv_uvmem.c
> +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
> @@ -377,8 +377,7 @@ static int kvmppc_svm_migrate_page(struct vm_area_struct *vma,
>   	return ret;
>   }
>   
> -static int uv_migrate_mem_slot(struct kvm *kvm,
> -		const struct kvm_memory_slot *memslot)
> +int uv_migrate_mem_slot(struct kvm *kvm, const struct kvm_memory_slot *memslot)
>   {
>   	unsigned long gfn = memslot->base_gfn;
>   	unsigned long end;
>