ivshmem: add API for kernel space mapping

Let also kernel mode clients to use shared memory. Signed-off-by: Yuri Benditovich <yuri.benditovich@daynix.com>
virtio-win · May 5, 2020 · 1716901 · 1716901
1 parent e6d9d7a
commit 1716901
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Showing 2 changed files with 10 additions and 5 deletions.
diff --git a/ivshmem/Public.h b/ivshmem/Public.h
@@ -67,3 +67,4 @@ IVSHMEM_EVENT, *PIVSHMEM_EVENT;
 #define IOCTL_IVSHMEM_RELEASE_MMAP   CTL_CODE(FILE_DEVICE_UNKNOWN, 0x803, METHOD_BUFFERED, FILE_ANY_ACCESS)
 #define IOCTL_IVSHMEM_RING_DOORBELL  CTL_CODE(FILE_DEVICE_UNKNOWN, 0x804, METHOD_BUFFERED, FILE_ANY_ACCESS)
 #define IOCTL_IVSHMEM_REGISTER_EVENT CTL_CODE(FILE_DEVICE_UNKNOWN, 0x805, METHOD_BUFFERED, FILE_ANY_ACCESS)
+#define IOCTL_IVSHMEM_REQUEST_KMAP   CTL_CODE(FILE_DEVICE_UNKNOWN, 0x806, METHOD_BUFFERED, FILE_ANY_ACCESS)
diff --git a/ivshmem/Queue.c b/ivshmem/Queue.c
@@ -36,7 +36,8 @@ static NTSTATUS ioctl_request_mmap(
     const size_t          InputBufferLength,
     const size_t          OutputBufferLength,
     const WDFREQUEST      Request,
-    size_t              * BytesReturned
+    size_t              * BytesReturned,
+    BOOLEAN               ForKernel
 );
 
 static NTSTATUS ioctl_release_mmap(
@@ -108,9 +109,11 @@ IVSHMEMEvtIoDeviceControl(
             break;
 
         case IOCTL_IVSHMEM_REQUEST_MMAP:
-            status = ioctl_request_mmap(deviceContext, InputBufferLength, OutputBufferLength, Request, &bytesReturned);
+            status = ioctl_request_mmap(deviceContext, InputBufferLength, OutputBufferLength, Request, &bytesReturned, FALSE);
+            break;
+        case IOCTL_IVSHMEM_REQUEST_KMAP:
+            status = ioctl_request_mmap(deviceContext, InputBufferLength, OutputBufferLength, Request, &bytesReturned, TRUE);
             break;
-
         case IOCTL_IVSHMEM_RELEASE_MMAP:
             status = ioctl_release_mmap(deviceContext, Request, &bytesReturned);
             break;
@@ -235,7 +238,8 @@ static NTSTATUS ioctl_request_mmap(
     const size_t          InputBufferLength,
     const size_t          OutputBufferLength,
     const WDFREQUEST      Request,
-    size_t              * BytesReturned
+    size_t              * BytesReturned,
+    BOOLEAN               ForKernel
 )
 {
     // only one mapping at a time is allowed
@@ -291,7 +295,7 @@ static NTSTATUS ioctl_request_mmap(
     {
         DeviceContext->shmemMap = MmMapLockedPagesSpecifyCache(
           DeviceContext->shmemMDL,
-          UserMode,
+          ForKernel ? KernelMode : UserMode,
           cacheType,
           NULL,
           FALSE,