Change setup of virtual device support (o3de#17640)

Signed-off-by: Martin Winter <[email protected]>

Author: martinwinter-huawei

Gems/Atom/RHI/Code/Include/Atom/RHI/RHISystem.h

@@ -38,9 +38,9 @@ namespace AZ::RHI
         , public RHIMemoryStatisticsInterface
     {
     public:
-        //! This function just initializes the native device and RHI::Device as a result.
-        //! We can use this device to then query for device capabilities.
-        ResultCode InitDevices(InitDevicesFlags initializationVariant = InitDevicesFlags::SingleDevice);
+        //! This function just initializes the native devices and RHI::Device as a result.
+        //! We can use these devices to then query for device capabilities.
+        ResultCode InitDevices(int deviceCount = 1);
 
         //! This function initializes the rest of the RHI/RHI backend.
         //! bindlessSrgLayout in this case is layout associated with the bindless srg (Bindless.azsli).
@@ -97,7 +97,7 @@ namespace AZ::RHI
     private:
 
         //! Enumerates the Physical devices and picks one (or multiple) to be used to initialize the RHI::Device(s) with
-        ResultCode InitInternalDevices(InitDevicesFlags initializationVariant);
+        ResultCode InitInternalDevices(int deviceCount);
 
         AZStd::vector<DrawListTag> m_drawListTagsDisabledByDefault;
         AZStd::vector<RHI::Ptr<RHI::Device>> m_devices;

Gems/Atom/RHI/Code/Source/RHI/RHISystem.cpp

@@ -35,11 +35,11 @@ namespace AZ::RHI
         return Interface<RHIMemoryStatisticsInterface>::Get();
     }
 
-    ResultCode RHISystem::InitDevices(InitDevicesFlags initializationVariant)
+    ResultCode RHISystem::InitDevices(int deviceCount)
     {
         Interface<RHISystemInterface>::Register(this);
         Interface<RHIMemoryStatisticsInterface>::Register(this);
-        return InitInternalDevices(initializationVariant);
+        return InitInternalDevices(deviceCount);
     }
 
     void RHISystem::Init(RHI::Ptr<RHI::ShaderResourceGroupLayout> bindlessSrgLayout)
@@ -100,7 +100,7 @@ namespace AZ::RHI
         RHISystemNotificationBus::Broadcast(&RHISystemNotificationBus::Events::OnRHISystemInitialized);
     }
 
-    ResultCode RHISystem::InitInternalDevices(InitDevicesFlags initializationVariant)
+    ResultCode RHISystem::InitInternalDevices(int deviceCount)
     {
         RHI::PhysicalDeviceList physicalDevices = RHI::Factory::Get().EnumeratePhysicalDevices();
 
@@ -114,7 +114,7 @@ namespace AZ::RHI
 
         RHI::PhysicalDeviceList usePhysicalDevices;
 
-        if (initializationVariant == InitDevicesFlags::MultiDevice)
+        if (deviceCount > 1)
         {
             AZ_Printf("RHISystem", "\tUsing multiple devices\n");
 
@@ -197,6 +197,14 @@ namespace AZ::RHI
             }
         }
 
+        for (auto index{ 0 }; m_devices.size() < deviceCount; index++)
+        {
+            // We do not have enough physical devices for the requested device count
+            // Virtualize the existing devices up to the required number
+            auto deviceIndex{ AddVirtualDevice(m_devices[index]->GetDeviceIndex()) };
+            AZ_Printf("RHISystem", "\tVirtualized device %d from device %d\n", deviceIndex.value(), m_devices[index]->GetDeviceIndex());
+        }
+
         if (m_devices.empty())
         {
             AZ_Error("RHISystem", false, "Failed to initialize RHI device.");

Gems/Atom/RHI/Code/Tests/DrawPacketTests.cpp

@@ -178,7 +178,7 @@ namespace UnitTest
             m_drawListTagRegistry = RHI::DrawListTagRegistry::Create();
 
             m_rhiSystem.reset(aznew AZ::RHI::RHISystem);
-            m_rhiSystem->InitDevices(AZ::RHI::InitDevicesFlags::SingleDevice);
+            m_rhiSystem->InitDevices();
             m_rhiSystem->Init();
         }
 

Gems/Atom/RHI/Code/Tests/RHITestFixture.h

@@ -22,6 +22,7 @@
 
 #include <Atom/RHI.Reflect/Base.h>
 #include <Atom/RHI/RHISystem.h>
+#include <Tests/Device.h>
 #include <Tests/Factory.h>
 
 namespace UnitTest
@@ -71,7 +72,7 @@ namespace UnitTest
 
             m_rhiSystem.reset(aznew AZ::RHI::RHISystem);
 
-            m_rhiSystem->InitDevices(AZ::RHI::InitDevicesFlags::MultiDevice);
+            m_rhiSystem->InitDevices(DeviceCount);
             m_rhiSystem->Init();
         }
 

Gems/Atom/RPI/Code/Source/RPI.Public/RPISystem.cpp

@@ -81,7 +81,8 @@ namespace AZ
         void RPISystem::Initialize(const RPISystemDescriptor& rpiSystemDescriptor)
         {
             // Init RHI device(s)
-            m_rhiSystem.InitDevices(AzFramework::StringFunc::Equal(RHI::GetCommandLineValue("enableMultipleDevices").c_str(), "enable") ? RHI::InitDevicesFlags::MultiDevice : RHI::InitDevicesFlags::SingleDevice);
+            auto commandLineMultipleDevicesValue{ RHI::GetCommandLineValue("device-count") };
+            m_rhiSystem.InitDevices((commandLineMultipleDevicesValue != "") ? AZStd::stoi(commandLineMultipleDevicesValue) : 1);
 
             // Gather asset handlers from sub-systems.
             ImageSystem::GetAssetHandlers(m_assetHandlers);