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

[Ram Pai]

On Tue, Jun 02, 2020 at 10:31:32AM +0200, Laurent Dufour wrote:
> Le 31/05/2020 à 04:27, Ram Pai a écrit :
> >From: Laurent Dufour <ldufour at 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 at ozlabs.org>
> >Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> >Cc: Michael Ellerman <mpe at ellerman.id.au>
> >Cc: Bharata B Rao <bharata at linux.ibm.com>
> >Cc: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>
> >Cc: Sukadev Bhattiprolu <sukadev at linux.vnet.ibm.com>
> >Cc: Laurent Dufour <ldufour at linux.ibm.com>
> >Cc: Thiago Jung Bauermann <bauerman at linux.ibm.com>
> >Cc: David Gibson <david at gibson.dropbear.id.au>
> >Cc: Claudio Carvalho <cclaudio at linux.ibm.com>
> >Cc: kvm-ppc at vger.kernel.org
> >Cc: linuxppc-dev at lists.ozlabs.org
> >Signed-off-by: Ram Pai <linuxram at us.ibm.com>
> >	(fixed merge conflicts. Modified the commit message)
> >Signed-off-by: Laurent Dufour <ldufour at 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!

Your patch is rebased on top of my patches. This prototype declaration
is for the ifndef CONFIG_PPC_UV   case.

> 
> 
> >  #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.

yes. i did add another parameter to kvmppc_uvmem_drop_pages() in my
patch series. So had to adapt your patch to operate on top my mine.
> 
> Is that series really building?

yes. it built for me.

RP