KVM: set_memory_region: Refactor commit_memory_region()

This patch makes the parameter old a const pointer to the old memory
slot and adds a new parameter named change to know the change being
requested: the former is for removing extra copying and the latter is
for cleaning up the code.

Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

11 files changed, 24 insertions, 18 deletions

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 96ebab7a1959..b32dc446e802 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -238,7 +238,8 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 
 void kvm_arch_commit_memory_region(struct kvm *kvm,
                                    struct kvm_userspace_memory_region *mem,
-                                   struct kvm_memory_slot old)
+                                   const struct kvm_memory_slot *old,
+                                   enum kvm_mr_change change)
 {
 }
 
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 5c2b07e8c3d6..7a54455dde39 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1591,7 +1591,8 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 
 void kvm_arch_commit_memory_region(struct kvm *kvm,
                 struct kvm_userspace_memory_region *mem,
-                struct kvm_memory_slot old)
+                const struct kvm_memory_slot *old,
+                enum kvm_mr_change change)
 {
         return;
 }
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 44a657adf416..44fa9ad1d62c 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -152,7 +152,7 @@ extern int kvmppc_core_prepare_memory_region(struct kvm *kvm,
                                 struct kvm_userspace_memory_region *mem);
 extern void kvmppc_core_commit_memory_region(struct kvm *kvm,
                                 struct kvm_userspace_memory_region *mem,
-                                struct kvm_memory_slot old);
+                                const struct kvm_memory_slot *old);
 extern int kvm_vm_ioctl_get_smmu_info(struct kvm *kvm,
                                       struct kvm_ppc_smmu_info *info);
 extern void kvmppc_core_flush_memslot(struct kvm *kvm,
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 80dcc53a1aba..1e521baf9a7d 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1639,12 +1639,12 @@ int kvmppc_core_prepare_memory_region(struct kvm *kvm,
 
 void kvmppc_core_commit_memory_region(struct kvm *kvm,
                                       struct kvm_userspace_memory_region *mem,
-                                      struct kvm_memory_slot old)
+                                      const struct kvm_memory_slot *old)
 {
         unsigned long npages = mem->memory_size >> PAGE_SHIFT;
         struct kvm_memory_slot *memslot;
 
-        if (npages && old.npages) {
+        if (npages && old->npages) {
                 /*
                  * If modifying a memslot, reset all the rmap dirty bits.
                  * If this is a new memslot, we don't need to do anything
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 5e93438afb06..286e23e6b92d 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -1283,7 +1283,7 @@ int kvmppc_core_prepare_memory_region(struct kvm *kvm,
 
 void kvmppc_core_commit_memory_region(struct kvm *kvm,
                                 struct kvm_userspace_memory_region *mem,
-                                struct kvm_memory_slot old)
+                                const struct kvm_memory_slot *old)
 {
 }
 
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 020923e43134..eb88fa621073 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -1531,7 +1531,7 @@ int kvmppc_core_prepare_memory_region(struct kvm *kvm,
 
 void kvmppc_core_commit_memory_region(struct kvm *kvm,
                                 struct kvm_userspace_memory_region *mem,
-                                struct kvm_memory_slot old)
+                                const struct kvm_memory_slot *old)
 {
 }
 
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 8aa51cd67c28..7b5d4d20cdc5 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -420,7 +420,8 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 
 void kvm_arch_commit_memory_region(struct kvm *kvm,
                                    struct kvm_userspace_memory_region *mem,
-                                   struct kvm_memory_slot old)
+                                   const struct kvm_memory_slot *old,
+                                   enum kvm_mr_change change)
 {
         kvmppc_core_commit_memory_region(kvm, mem, old);
 }
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 4288780c86b8..6cae4ad647a9 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1001,7 +1001,8 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 
 void kvm_arch_commit_memory_region(struct kvm *kvm,
                                 struct kvm_userspace_memory_region *mem,
-                                struct kvm_memory_slot old)
+                                const struct kvm_memory_slot *old,
+                                enum kvm_mr_change change)
 {
         int rc;
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7198234fa088..35b491229c3a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6935,16 +6935,17 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 
 void kvm_arch_commit_memory_region(struct kvm *kvm,
                                 struct kvm_userspace_memory_region *mem,
-                                struct kvm_memory_slot old)
+                                const struct kvm_memory_slot *old,
+                                enum kvm_mr_change change)
 {
 
-        int nr_mmu_pages = 0, npages = mem->memory_size >> PAGE_SHIFT;
+        int nr_mmu_pages = 0;
 
-        if ((mem->slot >= KVM_USER_MEM_SLOTS) && old.npages && !npages) {
+        if ((mem->slot >= KVM_USER_MEM_SLOTS) && (change == KVM_MR_DELETE)) {
                 int ret;
 
-                ret = vm_munmap(old.userspace_addr,
-                                old.npages * PAGE_SIZE);
+                ret = vm_munmap(old->userspace_addr,
+                                old->npages * PAGE_SIZE);
                 if (ret < 0)
                         printk(KERN_WARNING
                                "kvm_vm_ioctl_set_memory_region: "
@@ -6961,13 +6962,13 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
          * Existing largepage mappings are destroyed here and new ones will
          * not be created until the end of the logging.
          */
-        if (npages && (mem->flags & KVM_MEM_LOG_DIRTY_PAGES))
+        if ((change != KVM_MR_DELETE) && (mem->flags & KVM_MEM_LOG_DIRTY_PAGES))
                 kvm_mmu_slot_remove_write_access(kvm, mem->slot);
         /*
          * If memory slot is created, or moved, we need to clear all
          * mmio sptes.
          */
-        if (npages && old.base_gfn != mem->guest_phys_addr >> PAGE_SHIFT) {
+        if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) {
                 kvm_mmu_zap_all(kvm);
                 kvm_reload_remote_mmus(kvm);
         }
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index caa72cf7e8e7..ac584cc53581 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -483,7 +483,8 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
                                 enum kvm_mr_change change);
 void kvm_arch_commit_memory_region(struct kvm *kvm,
                                 struct kvm_userspace_memory_region *mem,
-                                struct kvm_memory_slot old);
+                                const struct kvm_memory_slot *old,
+                                enum kvm_mr_change change);
 bool kvm_largepages_enabled(void);
 void kvm_disable_largepages(void);
 /* flush all memory translations */
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 8f85bae862c7..0e919a1d4d56 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -896,7 +896,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
 
         old_memslots = install_new_memslots(kvm, slots, &new);
 
-        kvm_arch_commit_memory_region(kvm, mem, old);
+        kvm_arch_commit_memory_region(kvm, mem, &old, change);
 
         kvm_free_physmem_slot(&old, &new);
         kfree(old_memslots);