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

From: Ram Pai <[email-masked]>
Date: Sat, 30 May 2020 19:27:51 -0700

From: Laurent Dufour <[email-masked]>

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 <[email-masked]>
Cc: Benjamin Herrenschmidt <[email-masked]>
Cc: Michael Ellerman <[email-masked]>
Cc: Bharata B Rao <[email-masked]>
Cc: Aneesh Kumar K.V <[email-masked]>
Cc: Sukadev Bhattiprolu <[email-masked]>
Cc: Laurent Dufour <[email-masked]>
Cc: Thiago Jung Bauermann <[email-masked]>
Cc: David Gibson <[email-masked]>
Cc: Claudio Carvalho <[email-masked]>
Cc: [email-masked]
Cc: [email-masked]
Signed-off-by: Ram Pai <[email-masked]>
	(fixed merge conflicts. Modified the commit message)
Signed-off-by: Laurent Dufour <[email-masked]>
---
 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);
 #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);
 		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;
-- 
1.8.3.1