[PATCH v3 kvm/queue 15/16] KVM: Use kvm_userspace_memory_region_ext

[Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>]

Use the new extended memslot structure kvm_userspace_memory_region_ext
which includes two additional fd/ofs fields comparing to the current
kvm_userspace_memory_region. The fields fd/ofs will be copied from
userspace only when KVM_MEM_PRIVATE is set.

Internal the KVM we change all existing kvm_userspace_memory_region to
kvm_userspace_memory_region_ext since the new extended structure covers
all the existing fields in kvm_userspace_memory_region.

Signed-off-by: Yu Zhang <yu.c.zhang@xxxxxxxxxxxxxxx>
Signed-off-by: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>
---
 arch/x86/kvm/x86.c       |  2 +-
 include/linux/kvm_host.h |  4 ++--
 virt/kvm/kvm_main.c      | 19 +++++++++++++------
 3 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 42bde45a1bc2..52942195def3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11551,7 +11551,7 @@ void __user * __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa,
 	}
 
 	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
-		struct kvm_userspace_memory_region m;
+		struct kvm_userspace_memory_region_ext m;
 
 		m.slot = id | (i << 16);
 		m.flags = 0;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ad89a0e8bf6b..fabab3b77d57 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -981,9 +981,9 @@ enum kvm_mr_change {
 };
 
 int kvm_set_memory_region(struct kvm *kvm,
-			  const struct kvm_userspace_memory_region *mem);
+			  const struct kvm_userspace_memory_region_ext *mem);
 int __kvm_set_memory_region(struct kvm *kvm,
-			    const struct kvm_userspace_memory_region *mem);
+			    const struct kvm_userspace_memory_region_ext *mem);
 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,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 36dd2adcd7fc..cf8dcb3b8c7f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1514,7 +1514,7 @@ static void kvm_replace_memslot(struct kvm *kvm,
 	}
 }
 
-static int check_memory_region_flags(const struct kvm_userspace_memory_region *mem)
+static int check_memory_region_flags(const struct kvm_userspace_memory_region_ext *mem)
 {
 	u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
 
@@ -1907,7 +1907,7 @@ static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id,
  * Must be called holding kvm->slots_lock for write.
  */
 int __kvm_set_memory_region(struct kvm *kvm,
-			    const struct kvm_userspace_memory_region *mem)
+			    const struct kvm_userspace_memory_region_ext *mem)
 {
 	struct kvm_memory_slot *old, *new;
 	struct kvm_memslots *slots;
@@ -2011,7 +2011,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
 EXPORT_SYMBOL_GPL(__kvm_set_memory_region);
 
 int kvm_set_memory_region(struct kvm *kvm,
-			  const struct kvm_userspace_memory_region *mem)
+			  const struct kvm_userspace_memory_region_ext *mem)
 {
 	int r;
 
@@ -2023,7 +2023,7 @@ int kvm_set_memory_region(struct kvm *kvm,
 EXPORT_SYMBOL_GPL(kvm_set_memory_region);
 
 static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
-					  struct kvm_userspace_memory_region *mem)
+				struct kvm_userspace_memory_region_ext *mem)
 {
 	if ((u16)mem->slot >= KVM_USER_MEM_SLOTS)
 		return -EINVAL;
@@ -4569,12 +4569,19 @@ static long kvm_vm_ioctl(struct file *filp,
 		break;
 	}
 	case KVM_SET_USER_MEMORY_REGION: {
-		struct kvm_userspace_memory_region kvm_userspace_mem;
+		struct kvm_userspace_memory_region_ext kvm_userspace_mem;
 
 		r = -EFAULT;
 		if (copy_from_user(&kvm_userspace_mem, argp,
-						sizeof(kvm_userspace_mem)))
+				sizeof(struct kvm_userspace_memory_region)))
 			goto out;
+		if (kvm_userspace_mem.flags & KVM_MEM_PRIVATE) {
+			int offset = offsetof(
+				struct kvm_userspace_memory_region_ext, ofs);
+			if (copy_from_user(&kvm_userspace_mem.ofs, argp + offset,
+					   sizeof(kvm_userspace_mem) - offset))
+				goto out;
+		}
 
 		r = kvm_vm_ioctl_set_memory_region(kvm, &kvm_userspace_mem);
 		break;
-- 
2.17.1