[RFC 3/7] gpu: nova-core: introduce vgpu_support module param.

[Zhi Wang <zhiw@nvidia.com>]

Introduce a kernel module param to set vGPU support in nova-core.

vgpu_support = 1 (default): automatic

The driver automatically enables or disables vGPU support based on if the
GPU advertises SRIOV caps.

vgpu_support = 0: disabled

Explicitly disables vGPU support. The driver will not enable vGPU support
regardless.

Signed-off-by: Zhi Wang <zhiw@nvidia.com>
---
 drivers/gpu/nova-core/gpu.rs       |  4 ++++
 drivers/gpu/nova-core/nova_core.rs | 15 +++++++++++++++
 drivers/gpu/nova-core/vgpu.rs      | 26 ++++++++++++++++++++++++++
 3 files changed, 45 insertions(+)
 create mode 100644 drivers/gpu/nova-core/vgpu.rs

diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 629c9d2dc994..10c5ae07a891 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -20,6 +20,7 @@
     gfw,
     gsp::Gsp,
     regs,
+    vgpu::Vgpu, //
 };
 
 macro_rules! define_chipset {
@@ -252,6 +253,7 @@ pub(crate) struct Gpu {
     /// GSP runtime data. Temporarily an empty placeholder.
     #[pin]
     gsp: Gsp,
+    vgpu: Vgpu,
 }
 
 impl Gpu {
@@ -271,6 +273,8 @@ pub(crate) fn new<'a>(
                     .inspect_err(|_| dev_err!(pdev.as_ref(), "GFW boot did not complete"))?;
             },
 
+            vgpu: Vgpu::new(pdev)?,
+
             sysmem_flush: SysmemFlush::register(pdev.as_ref(), bar, spec.chipset)?,
 
             gsp_falcon: Falcon::new(
diff --git a/drivers/gpu/nova-core/nova_core.rs b/drivers/gpu/nova-core/nova_core.rs
index b98a1c03f13d..e034353f69ab 100644
--- a/drivers/gpu/nova-core/nova_core.rs
+++ b/drivers/gpu/nova-core/nova_core.rs
@@ -18,6 +18,7 @@
 mod sbuffer;
 mod util;
 mod vbios;
+mod vgpu;
 
 pub(crate) const MODULE_NAME: &kernel::str::CStr = <LocalModule as kernel::ModuleMetadata>::NAME;
 
@@ -28,6 +29,20 @@
     description: "Nova Core GPU driver",
     license: "GPL v2",
     firmware: [],
+    params: {
+        // vgpu_support = 1 (default): automatic
+        //
+        // The driver automatically enables or disables vGPU support based on if the GPU
+        // advertises SRIOV caps.
+        //
+        // vgpu_support = 0: disabled
+        //
+        // Explicitly disables vGPU support. The driver will not enable vGPU support regardless.
+        vgpu_support: u32 {
+            default: 1,
+            description: "Enable vGPU support - (1 = auto (default), 0 = disable)",
+        },
+    },
 }
 
 kernel::module_firmware!(firmware::ModInfoBuilder);
diff --git a/drivers/gpu/nova-core/vgpu.rs b/drivers/gpu/nova-core/vgpu.rs
new file mode 100644
index 000000000000..9701b97bf6bf
--- /dev/null
+++ b/drivers/gpu/nova-core/vgpu.rs
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+use kernel::{
+    device,
+    pci,
+    prelude::*, //
+};
+
+use crate::{
+    module_parameters, //
+};
+
+pub(crate) struct Vgpu {
+    pub vgpu_support: bool,
+}
+
+impl Vgpu {
+    pub(crate) fn new(pdev: &pci::Device<device::Bound>) -> Result<Vgpu> {
+        Ok(Vgpu {
+            vgpu_support: match *module_parameters::vgpu_support.value() {
+                0 => false,
+                _ => pdev.sriov_get_totalvfs().is_ok(),
+            },
+        })
+    }
+}
-- 
2.51.0