[PATCH v5 03/13] KVM: Add "old" memslot parameter to kvm_arch_prepare_memory_region()

["Maciej S. Szmigiero" <mail@maciej.szmigiero.name>]

From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com>

This is needed for the next commit, which moves n_memslots_pages
recalculation from kvm_arch_commit_memory_region() to the aforementioned
function to allow for returning an error code.

While we are at it let's also rename the "memslot" parameter to "new" for
consistency with kvm_arch_commit_memory_region(), which uses the same
argument set now.

No functional change intended.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
---
 arch/arm64/kvm/mmu.c       | 7 ++++---
 arch/mips/kvm/mips.c       | 3 ++-
 arch/powerpc/kvm/powerpc.c | 5 +++--
 arch/s390/kvm/kvm-s390.c   | 3 ++-
 arch/x86/kvm/x86.c         | 5 +++--
 include/linux/kvm_host.h   | 3 ++-
 virt/kvm/kvm_main.c        | 2 +-
 7 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 1a94a7ca48f2..6d93ae1edb6d 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1486,7 +1486,8 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
 }
 
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
-				   struct kvm_memory_slot *memslot,
+				   const struct kvm_memory_slot *old,
+				   struct kvm_memory_slot *new,
 				   const struct kvm_userspace_memory_region *mem,
 				   enum kvm_mr_change change)
 {
@@ -1502,7 +1503,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 	 * Prevent userspace from creating a memory region outside of the IPA
 	 * space addressable by the KVM guest IPA space.
 	 */
-	if ((memslot->base_gfn + memslot->npages) > (kvm_phys_size(kvm) >> PAGE_SHIFT))
+	if ((new->base_gfn + new->npages) > (kvm_phys_size(kvm) >> PAGE_SHIFT))
 		return -EFAULT;
 
 	mmap_read_lock(current->mm);
@@ -1534,7 +1535,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 
 		if (vma->vm_flags & VM_PFNMAP) {
 			/* IO region dirty page logging not allowed */
-			if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES) {
+			if (new->flags & KVM_MEM_LOG_DIRTY_PAGES) {
 				ret = -EINVAL;
 				break;
 			}
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 75c6f264c626..8587c260c6fb 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -233,7 +233,8 @@ void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
 }
 
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
-				   struct kvm_memory_slot *memslot,
+				   const struct kvm_memory_slot *old,
+				   struct kvm_memory_slot *new,
 				   const struct kvm_userspace_memory_region *mem,
 				   enum kvm_mr_change change)
 {
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index b4e6f70b97b9..6ecb6a51d82f 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -706,11 +706,12 @@ void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
 }
 
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
-				   struct kvm_memory_slot *memslot,
+				   const struct kvm_memory_slot *old,
+				   struct kvm_memory_slot *new,
 				   const struct kvm_userspace_memory_region *mem,
 				   enum kvm_mr_change change)
 {
-	return kvmppc_core_prepare_memory_region(kvm, memslot, mem, change);
+	return kvmppc_core_prepare_memory_region(kvm, new, mem, change);
 }
 
 void kvm_arch_commit_memory_region(struct kvm *kvm,
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 752a0ffab9bf..3fd0f4afe742 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -5016,7 +5016,8 @@ vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
 
 /* Section: memory related */
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
-				   struct kvm_memory_slot *memslot,
+				   const struct kvm_memory_slot *old,
+				   struct kvm_memory_slot *new,
 				   const struct kvm_userspace_memory_region *mem,
 				   enum kvm_mr_change change)
 {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2e4fe2511c5d..97d86223427d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11506,12 +11506,13 @@ void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen)
 }
 
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
-				struct kvm_memory_slot *memslot,
+				const struct kvm_memory_slot *old,
+				struct kvm_memory_slot *new,
 				const struct kvm_userspace_memory_region *mem,
 				enum kvm_mr_change change)
 {
 	if (change == KVM_MR_CREATE || change == KVM_MR_MOVE)
-		return kvm_alloc_memslot_metadata(kvm, memslot,
+		return kvm_alloc_memslot_metadata(kvm, new,
 						  mem->memory_size >> PAGE_SHIFT);
 	return 0;
 }
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 041ca7f15ea4..c6963f6f1eb8 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -832,7 +832,8 @@ int __kvm_set_memory_region(struct kvm *kvm,
 void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot);
 void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen);
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
-				struct kvm_memory_slot *memslot,
+				const struct kvm_memory_slot *old,
+				struct kvm_memory_slot *new,
 				const struct kvm_userspace_memory_region *mem,
 				enum kvm_mr_change change);
 void kvm_arch_commit_memory_region(struct kvm *kvm,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 439d3b4cd1a9..c3c71a9e85c9 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1571,7 +1571,7 @@ static int kvm_set_memslot(struct kvm *kvm,
 		kvm_copy_memslots(slots, __kvm_memslots(kvm, as_id));
 	}
 
-	r = kvm_arch_prepare_memory_region(kvm, new, mem, change);
+	r = kvm_arch_prepare_memory_region(kvm, old, new, mem, change);
 	if (r)
 		goto out_slots;