[PATCH v5 06/13] KVM: Use kvm_userspace_memory_region_ext

[Chao Peng]

Use the new extended memslot structure kvm_userspace_memory_region_ext.
The extended part (private_fd/ private_offset) will be copied from
userspace only when KVM_MEM_PRIVATE is set. Internally old
kvm_userspace_memory_region will still be used for places where the
extended fields are not needed.

Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
---
 arch/x86/kvm/x86.c       | 12 ++++++------
 include/linux/kvm_host.h |  4 ++--
 virt/kvm/kvm_main.c      | 30 ++++++++++++++++++++----------
 3 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8c06b8204fca..1d9dbef67715 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11757,13 +11757,13 @@ 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;
-               m.guest_phys_addr = gpa;
-               m.userspace_addr = hva;
-               m.memory_size = size;
+               m.region.slot = id | (i << 16);
+               m.region.flags = 0;
+               m.region.guest_phys_addr = gpa;
+               m.region.userspace_addr = hva;
+               m.region.memory_size = size;
                r = __kvm_set_memory_region(kvm, &m);
                if (r < 0)
                        return ERR_PTR_USR(r);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 3be8116079d4..c92c70174248 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1082,9 +1082,9 @@ 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 *region_ext);
 int __kvm_set_memory_region(struct kvm *kvm,
-                           const struct kvm_userspace_memory_region *mem);
+               const struct kvm_userspace_memory_region_ext *region_ext);
 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 69c318fdff61..d11a2628b548 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1809,8 +1809,9 @@ 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 *region_ext)
 {
+       const struct kvm_userspace_memory_region *mem = &region_ext->region;
        struct kvm_memory_slot *old, *new;
        struct kvm_memslots *slots;
        enum kvm_mr_change change;
@@ -1913,24 +1914,24 @@ 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 *region_ext)
 {
        int r;
 
        mutex_lock(&kvm->slots_lock);
-       r = __kvm_set_memory_region(kvm, mem);
+       r = __kvm_set_memory_region(kvm, region_ext);
        mutex_unlock(&kvm->slots_lock);
        return r;
 }
 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 *region_ext)
 {
-       if ((u16)mem->slot >= KVM_USER_MEM_SLOTS)
+       if ((u16)region_ext->region.slot >= KVM_USER_MEM_SLOTS)
                return -EINVAL;
 
-       return kvm_set_memory_region(kvm, mem);
+       return kvm_set_memory_region(kvm, region_ext);
 }
 
 #ifndef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
@@ -4476,14 +4477,23 @@ 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 region_ext;
 
                r = -EFAULT;
-               if (copy_from_user(&kvm_userspace_mem, argp,
-                                               sizeof(kvm_userspace_mem)))
+               if (copy_from_user(&region_ext, argp,
+                               sizeof(struct kvm_userspace_memory_region)))
                        goto out;
+               if (region_ext.region.flags & KVM_MEM_PRIVATE) {
+                       int offset = offsetof(
+                               struct kvm_userspace_memory_region_ext,
+                               private_offset);
+                       if (copy_from_user(&region_ext.private_offset,
+                                          argp + offset,
+                                          sizeof(region_ext) - offset))
+                               goto out;
+               }
 
-               r = kvm_vm_ioctl_set_memory_region(kvm, &kvm_userspace_mem);
+               r = kvm_vm_ioctl_set_memory_region(kvm, &region_ext);
                break;
        }
        case KVM_GET_DIRTY_LOG: {
-- 
2.17.1