gpu: nova-core: gsp: add tests for continuation records

Add tests for continuation record splitting. They cover boundary
conditions at the split points to make sure the right number of
continuation records are made. They also check that the data
concatenated is correct.

Tested-by: Zhi Wang <zhiw@nvidia.com>
Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
Link: https://patch.msgid.link/20260306-cmdq-continuation-v6-9-cc7b629200ee@nvidia.com
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>

diff --git a/drivers/gpu/nova-core/gsp/cmdq/continuation.rs b/drivers/gpu/nova-core/gsp/cmdq/continuation.rs
index 67b3e03fd8ea576376e38ef6ba7853f05c2dc242..2aa17caac2e0c7ab073759c3b5919fe4da427fd6 100644 (file)
--- a/drivers/gpu/nova-core/gsp/cmdq/continuation.rs
+++ b/drivers/gpu/nova-core/gsp/cmdq/continuation.rs
@@ -161,3 +161,141 @@ impl<C: CommandToGsp> CommandToGsp for SplitCommand<C> {
         dst.write_all(&self.payload)
     }
 }
+
+#[kunit_tests(nova_core_gsp_continuation)]
+mod tests {
+    use super::*;
+
+    use kernel::transmute::{
+        AsBytes,
+        FromBytes, //
+    };
+
+    /// Non-zero-sized command header for testing.
+    #[repr(C)]
+    #[derive(Clone, Copy, Zeroable)]
+    struct TestHeader([u8; 64]);
+
+    // SAFETY: `TestHeader` is a plain array of bytes for which all bit patterns are valid.
+    unsafe impl FromBytes for TestHeader {}
+
+    // SAFETY: `TestHeader` is a plain array of bytes for which all bit patterns are valid.
+    unsafe impl AsBytes for TestHeader {}
+
+    struct TestPayload {
+        data: KVVec<u8>,
+    }
+
+    impl TestPayload {
+        fn generate_pattern(len: usize) -> Result<KVVec<u8>> {
+            let mut data = KVVec::with_capacity(len, GFP_KERNEL)?;
+            for i in 0..len {
+                // Mix in higher bits so the pattern does not repeat every 256 bytes.
+                data.push((i ^ (i >> 8)) as u8, GFP_KERNEL)?;
+            }
+            Ok(data)
+        }
+
+        fn new(len: usize) -> Result<Self> {
+            Ok(Self {
+                data: Self::generate_pattern(len)?,
+            })
+        }
+    }
+
+    impl CommandToGsp for TestPayload {
+        const FUNCTION: MsgFunction = MsgFunction::Nop;
+        type Command = TestHeader;
+        type InitError = Infallible;
+
+        fn init(&self) -> impl Init<Self::Command, Self::InitError> {
+            TestHeader::init_zeroed()
+        }
+
+        fn variable_payload_len(&self) -> usize {
+            self.data.len()
+        }
+
+        fn init_variable_payload(
+            &self,
+            dst: &mut SBufferIter<core::array::IntoIter<&mut [u8], 2>>,
+        ) -> Result {
+            dst.write_all(self.data.as_slice())
+        }
+    }
+
+    /// Maximum variable payload size that fits in the first command alongside the header.
+    const MAX_FIRST_PAYLOAD: usize = SplitState::<TestPayload>::MAX_FIRST_PAYLOAD;
+
+    fn read_payload(cmd: impl CommandToGsp) -> Result<KVVec<u8>> {
+        let len = cmd.variable_payload_len();
+        let mut buf = KVVec::from_elem(0u8, len, GFP_KERNEL)?;
+        let mut sbuf = SBufferIter::new_writer([buf.as_mut_slice(), &mut []]);
+        cmd.init_variable_payload(&mut sbuf)?;
+        drop(sbuf);
+        Ok(buf)
+    }
+
+    struct SplitTest {
+        payload_size: usize,
+        num_continuations: usize,
+    }
+
+    fn check_split(t: SplitTest) -> Result {
+        let payload = TestPayload::new(t.payload_size)?;
+        let mut num_continuations = 0;
+
+        let buf = match SplitState::new(payload)? {
+            SplitState::Single(cmd) => read_payload(cmd)?,
+            SplitState::Split(cmd, mut continuations) => {
+                let mut buf = read_payload(cmd)?;
+                assert!(size_of::<TestHeader>() + buf.len() <= MAX_CMD_SIZE);
+
+                while let Some(cont) = continuations.next() {
+                    let payload = read_payload(cont)?;
+                    assert!(payload.len() <= MAX_CMD_SIZE);
+                    buf.extend_from_slice(&payload, GFP_KERNEL)?;
+                    num_continuations += 1;
+                }
+
+                buf
+            }
+        };
+
+        assert_eq!(num_continuations, t.num_continuations);
+        assert_eq!(
+            buf.as_slice(),
+            TestPayload::generate_pattern(t.payload_size)?.as_slice()
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn split_command() -> Result {
+        check_split(SplitTest {
+            payload_size: 0,
+            num_continuations: 0,
+        })?;
+        check_split(SplitTest {
+            payload_size: MAX_FIRST_PAYLOAD,
+            num_continuations: 0,
+        })?;
+        check_split(SplitTest {
+            payload_size: MAX_FIRST_PAYLOAD + 1,
+            num_continuations: 1,
+        })?;
+        check_split(SplitTest {
+            payload_size: MAX_FIRST_PAYLOAD + MAX_CMD_SIZE,
+            num_continuations: 1,
+        })?;
+        check_split(SplitTest {
+            payload_size: MAX_FIRST_PAYLOAD + MAX_CMD_SIZE + 1,
+            num_continuations: 2,
+        })?;
+        check_split(SplitTest {
+            payload_size: MAX_FIRST_PAYLOAD + MAX_CMD_SIZE * 3 + MAX_CMD_SIZE / 2,
+            num_continuations: 4,
+        })?;
+        Ok(())
+    }
+}