Nouveau - Dec 2025 - [RFC 5/7] gpu: nova-core: set RMSetSriovMode when NVIDIA vGPU is enabled

The registry object "RMSetSriovMode" is required to be set when vGPU
is
enabled.

Set "RMSetSriovMode" to 1 when nova-core is loading the GSP firmware
and
initialize the GSP registry objects, if vGPU is enabled.

Signed-off-by: Zhi Wang <zhiw at nvidia.com>
---
 drivers/gpu/nova-core/gsp/boot.rs     |  3 ++-
 drivers/gpu/nova-core/gsp/commands.rs | 23 +++++++++++++++--------
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/nova-core/gsp/boot.rs
b/drivers/gpu/nova-core/gsp/boot.rs
index 5016c630cec3..847ce550eccf 100644
--- a/drivers/gpu/nova-core/gsp/boot.rs
+++ b/drivers/gpu/nova-core/gsp/boot.rs
@@ -168,7 +168,8 @@ pub(crate) fn boot(
 
         self.cmdq
             .send_command(bar, commands::SetSystemInfo::new(pdev, vf_info))?;
-        self.cmdq.send_command(bar, commands::SetRegistry::new())?;
+        self.cmdq
+            .send_command(bar, commands::SetRegistry::new(vgpu_support))?;
 
         gsp_falcon.reset(bar)?;
         let libos_handle = self.libos.dma_handle();
diff --git a/drivers/gpu/nova-core/gsp/commands.rs
b/drivers/gpu/nova-core/gsp/commands.rs
index 1d519c4ed232..00ba48a25444 100644
--- a/drivers/gpu/nova-core/gsp/commands.rs
+++ b/drivers/gpu/nova-core/gsp/commands.rs
@@ -64,16 +64,18 @@ struct RegistryEntry {
 
 /// The `SetRegistry` command.
 pub(crate) struct SetRegistry {
-    entries: [RegistryEntry; Self::NUM_ENTRIES],
+    entries: [RegistryEntry; Self::MAX_NUM_ENTRIES],
+    num_entries: usize,
 }
 
 impl SetRegistry {
     // For now we hard-code the registry entries. Future work will allow others
to
     // be added as module parameters.
-    const NUM_ENTRIES: usize = 3;
+    const MAX_NUM_ENTRIES: usize = 4;
 
     /// Creates a new `SetRegistry` command, using a set of hardcoded entries.
-    pub(crate) fn new() -> Self {
+    pub(crate) fn new(vgpu_support: bool) -> Self {
+        let num_entries = if vgpu_support { 4 } else { 3 };
         Self {
             entries: [
                 // RMSecBusResetEnable - enables PCI secondary bus reset
@@ -93,7 +95,12 @@ pub(crate) fn new() -> Self {
                     key: "RMDevidCheckIgnore",
                     value: 1,
                 },
+                RegistryEntry {
+                    key: "RMSetSriovMode",
+                    value: 1,
+                },
             ],
+            num_entries,
         }
     }
 }
@@ -104,15 +111,15 @@ impl CommandToGsp for SetRegistry {
     type InitError = Infallible;
 
     fn init(&self) -> impl Init<Self::Command, Self::InitError> {
-        PackedRegistryTable::init(Self::NUM_ENTRIES as u32,
self.variable_payload_len() as u32)
+        PackedRegistryTable::init(self.num_entries as u32,
self.variable_payload_len() as u32)
     }
 
     fn variable_payload_len(&self) -> usize {
         let mut key_size = 0;
-        for i in 0..Self::NUM_ENTRIES {
+        for i in 0..self.num_entries {
             key_size += self.entries[i].key.len() + 1; // +1 for NULL
terminator
         }
-        Self::NUM_ENTRIES * size_of::<PackedRegistryEntry>() + key_size
+        self.num_entries * size_of::<PackedRegistryEntry>() + key_size
     }
 
     fn init_variable_payload(
@@ -120,12 +127,12 @@ fn init_variable_payload(
         dst: &mut SBufferIter<core::array::IntoIter<&mut [u8],
2>>,
     ) -> Result {
         let string_data_start_offset -           
size_of::<PackedRegistryTable>() + Self::NUM_ENTRIES *
size_of::<PackedRegistryEntry>();
+            size_of::<PackedRegistryTable>() + self.num_entries *
size_of::<PackedRegistryEntry>();
 
         // Array for string data.
         let mut string_data = KVec::new();
 
-        for entry in self.entries.iter().take(Self::NUM_ENTRIES) {
+        for entry in self.entries.iter().take(self.num_entries) {
             dst.write_all(
                 PackedRegistryEntry::new(
                     (string_data_start_offset + string_data.len()) as u32,
-- 
2.51.0

On Sat, 2025-12-06 at 12:42 +0000, Zhi Wang wrote:
> -??? pub(crate) fn new() -> Self {
> +??? pub(crate) fn new(vgpu_support: bool) -> Self {
> +??????? let num_entries = if vgpu_support { 4 } else { 3 };
Instead of passing a bool, and then hard-coding the length based on that bool
(which would
require that RMSetSriovMode always be the last entry in the array), you need to
do what Nouveau
does: if VGPU is enabled, then dynamically append the entry to the array.