netkvm: init-time decide about maximum RX buffer size

Currently the driver always assume the maximim packet size is ~64K as it is compiled with RSC support. The initial reason was that if the RSC is disabled by admin (registry value of the driver), it can be turned on by command, i.e. without disable-enable. However this depends also on host features. If the host does not support the GUEST_TSOx, RSC will be reported to the OS as not supported but the buffers are still huge without any reason. (In such case the powershell reports IPv4 and IPv6 operational state as Off even if the RSC keywords are enabled). The commit moves the decision to initialization time - if the RSC is not supported, the buffers are sized accoring to MTU. The memory consumption is lower 16 times. Signed-off-by: Yuri Benditovich <[email protected]>
virtio-win · Nov 28, 2024 · 48cdf5f · 48cdf5f
1 parent 8860475
commit 48cdf5f
Showing 1 changed file with 14 additions and 9 deletions.
diff --git a/NetKVM/Common/ParaNdis_Common.cpp b/NetKVM/Common/ParaNdis_Common.cpp
@@ -863,15 +863,6 @@ NDIS_STATUS ParaNdis_InitializeContext(
         return status;
     }
 
-    pContext->MaxPacketSize.nMaxFullSizeOS = pContext->MaxPacketSize.nMaxDataSize + ETH_HEADER_SIZE;
-    pContext->MaxPacketSize.nMaxFullSizeHwTx = pContext->MaxPacketSize.nMaxFullSizeOS;
-#if PARANDIS_SUPPORT_RSC
-    pContext->MaxPacketSize.nMaxDataSizeHwRx = MAX_HW_RX_PACKET_SIZE;
-    pContext->MaxPacketSize.nMaxFullSizeOsRx = MAX_OS_RX_PACKET_SIZE;
-#else
-    pContext->MaxPacketSize.nMaxDataSizeHwRx = pContext->MaxPacketSize.nMaxFullSizeOS + ETH_PRIORITY_HEADER_SIZE;
-    pContext->MaxPacketSize.nMaxFullSizeOsRx = pContext->MaxPacketSize.nMaxFullSizeOS;
-#endif
     if (pContext->ulPriorityVlanSetting)
         pContext->MaxPacketSize.nMaxFullSizeHwTx = pContext->MaxPacketSize.nMaxFullSizeOS + ETH_PRIORITY_HEADER_SIZE;
 
@@ -930,6 +921,20 @@ NDIS_STATUS ParaNdis_InitializeContext(
 
     InitializeRSCState(pContext);
 
+    pContext->MaxPacketSize.nMaxFullSizeOS = pContext->MaxPacketSize.nMaxDataSize + ETH_HEADER_SIZE;
+    pContext->MaxPacketSize.nMaxFullSizeHwTx = pContext->MaxPacketSize.nMaxFullSizeOS;
+
+    if (pContext->RSC.bIPv4SupportedHW || pContext->RSC.bIPv6SupportedHW)
+    {
+        pContext->MaxPacketSize.nMaxDataSizeHwRx = MAX_HW_RX_PACKET_SIZE;
+        pContext->MaxPacketSize.nMaxFullSizeOsRx = MAX_OS_RX_PACKET_SIZE;
+    }
+    else
+    {
+        pContext->MaxPacketSize.nMaxDataSizeHwRx = pContext->MaxPacketSize.nMaxFullSizeOS + ETH_PRIORITY_HEADER_SIZE;
+        pContext->MaxPacketSize.nMaxFullSizeOsRx = pContext->MaxPacketSize.nMaxFullSizeOS;
+    }
+
     // now, after we checked the capabilities, we can initialize current
     // configuration of offload tasks
     ParaNdis_ResetOffloadSettings(pContext, NULL, NULL);