On Fri, Sep 16, 2022 at 04:14:29PM +0700, Bagas Sanjaya wrote:

On Thu, Sep 15, 2022 at 10:29:07PM +0800, Chao Peng wrote:

quoted

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index abd7c32126ce..c1fac1e9f820 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst

@@ -1319,7 +1319,7 @@ yet and must be cleared on entry.
 :Capability: KVM_CAP_USER_MEMORY
 :Architectures: all
 :Type: vm ioctl
-:Parameters: struct kvm_userspace_memory_region (in)
+:Parameters: struct kvm_userspace_memory_region(_ext) (in)
 :Returns: 0 on success, -1 on error
 
 ::

@@ -1332,9 +1332,18 @@ yet and must be cleared on entry.
 	__u64 userspace_addr; /* start of the userspace allocated memory */
   };
 
+  struct kvm_userspace_memory_region_ext {
+	struct kvm_userspace_memory_region region;
+	__u64 private_offset;
+	__u32 private_fd;
+	__u32 pad1;
+	__u64 pad2[14];
+  };
+
   /* for kvm_memory_region::flags */
   #define KVM_MEM_LOG_DIRTY_PAGES	(1UL << 0)
   #define KVM_MEM_READONLY	(1UL << 1)
+  #define KVM_MEM_PRIVATE		(1UL << 2)
 
 This ioctl allows the user to create, modify or delete a guest physical
 memory slot.  Bits 0-15 of "slot" specify the slot id and this value

@@ -1365,12 +1374,27 @@ It is recommended that the lower 21 bits of guest_phys_addr and userspace_addr
 be identical.  This allows large pages in the guest to be backed by large
 pages in the host.
 
-The flags field supports two flags: KVM_MEM_LOG_DIRTY_PAGES and
-KVM_MEM_READONLY.  The former can be set to instruct KVM to keep track of
-writes to memory within the slot.  See KVM_GET_DIRTY_LOG ioctl to know how to
-use it.  The latter can be set, if KVM_CAP_READONLY_MEM capability allows it,
-to make a new slot read-only.  In this case, writes to this memory will be
-posted to userspace as KVM_EXIT_MMIO exits.
+kvm_userspace_memory_region_ext includes all the kvm_userspace_memory_region
+fields. It also includes additional fields for some specific features. See
+below description of flags field for more information. It's recommended to use
+kvm_userspace_memory_region_ext in new userspace code.

Better say "kvm_userspace_memory_region_ext includes all fields of
kvm_userspace_memory_region struct, while also adds additional fields ..."

quoted

+
+The flags field supports below flags:

s/below/following/

quoted

+
+- KVM_MEM_LOG_DIRTY_PAGES can be set to instruct KVM to keep track of writes to
+  memory within the slot.  See KVM_GET_DIRTY_LOG ioctl to know how to use it.
+

Better say "... For more details, see KVM_GET_DIRTY_LOG."

quoted

+- KVM_MEM_READONLY can be set, if KVM_CAP_READONLY_MEM capability allows it, to
+  make a new slot read-only.  In this case, writes to this memory will be posted
+  to userspace as KVM_EXIT_MMIO exits.
+

Better say "if KVM_CAP_READONLY_MEM allows, KVM_MEM_READONLY makes a new
slot read-only ..."

quoted

+- KVM_MEM_PRIVATE can be set to indicate a new slot has private memory backed by
+  a file descirptor(fd) and the content of the private memory is invisible to
+  userspace. In this case, userspace should use private_fd/private_offset in
+  kvm_userspace_memory_region_ext to instruct KVM to provide private memory to
+  guest. Userspace should guarantee not to map the same pfn indicated by
+  private_fd/private_offset to different gfns with multiple memslots. Failed to
+  do this may result undefined behavior.
 

For the lists above,
s/can be set/

It all looks good, thanks!

Thanks. 

-- 
An old man doll... just what I always wanted! - Clara