From: Christian Bruel christian.bruel@foss.st.com
[ Upstream commit cc8e391067164f45f89b6132a5aaa18c33a0e32b ]
The pci_endpoint_test tests the 32-bit MSI range. However, the device might not have all vectors configured. For example, if msi_interrupts is 8 in the ep function space or if the MSI Multiple Message Capable value is configured as 4 (maximum 16 vectors).
In this case, do not attempt to run the test to avoid timeouts and directly return the error value.
Signed-off-by: Christian Bruel christian.bruel@foss.st.com Signed-off-by: Manivannan Sadhasivam mani@kernel.org Link: https://patch.msgid.link/20250804170916.3212221-2-christian.bruel@foss.st.co... Signed-off-by: Sasha Levin sashal@kernel.org ---
LLM Generated explanations, may be completely bogus:
YES
Explanation: - What it fixes: The endpoint host test currently tries every MSI/MSI-X vector in the nominal 32/2048 range even when the device only enabled fewer vectors. For disabled/out-of-range vectors, no interrupt ever arrives from the endpoint side, so the host side waits 1 second and fails with a timeout (-ETIMEDOUT) per attempt. This is both slow and semantically wrong: the error is “invalid vector” rather than “timeout”. - Core change: The patch adds an early range check using `pci_irq_vector()` before attempting to trigger an interrupt. If the requested vector is not valid for the device, it returns immediately with the error from `pci_irq_vector()` (typically -EINVAL), skipping the test and avoiding a 1s timeout. - Early check added: drivers/misc/pci_endpoint_test.c:441-444 - `irq = pci_irq_vector(pdev, msi_num - 1);` - `if (irq < 0) return irq;` - Trigger and wait unchanged otherwise: drivers/misc/pci_endpoint_test.c:445-456 - Post-wait verification now uses the pre-fetched `irq` value: drivers/misc/pci_endpoint_test.c:457-460 - Previous behavior (pre-patch): The test wrote the registers and waited up to 1s for completion, then only after success called `pci_irq_vector()` to compare the vector number. If the vector was actually invalid, the wait timed out first and the function returned -ETIMEDOUT, masking the real reason and wasting time. - Alignment with selftests: Kselftests iterate through the full MSI/MSI-X ranges and expect -EINVAL for disabled vectors in order to SKIP them rather than fail: - MSI test expects -EINVAL to SKIP: tools/testing/selftests/pci_endpoint/pci_endpoint_test.c:122-127 - MSI-X test expects -EINVAL to SKIP: tools/testing/selftests/pci_endpoint/pci_endpoint_test.c:140-145 This change makes the driver return -EINVAL for out-of-range vectors, matching selftests and preventing spurious failures/timeouts. - Scope and risk: - Small, contained change in a single helper: drivers/misc/pci_endpoint_test.c:434-461. - No architectural changes; only the order of operations and error path are adjusted. - `pci_irq_vector()` has well-defined semantics and returns -EINVAL for out-of-range vectors (drivers/pci/msi/api.c:309-320). - Functional behavior for valid vectors is unchanged; the post-wait check still verifies the exact IRQ delivered (`irq == test->last_irq`). - The only user-visible change is the error code for invalid vectors (-EINVAL instead of -ETIMEDOUT), which aligns with the intended API usage and the selftests. - Backport criteria: - Fixes a real user-visible issue (spurious timeouts and failing tests when not all vectors are configured). - Minimal and low risk; confined to the pci_endpoint_test driver. - No new features; no impact on core PCI or IRQ subsystems. - Improves test reliability and reduces needless delays.
Given these points, this is a good candidate for stable backport.
drivers/misc/pci_endpoint_test.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c index f935175d8bf55..506a2847e5d22 100644 --- a/drivers/misc/pci_endpoint_test.c +++ b/drivers/misc/pci_endpoint_test.c @@ -436,7 +436,11 @@ static int pci_endpoint_test_msi_irq(struct pci_endpoint_test *test, { struct pci_dev *pdev = test->pdev; u32 val; - int ret; + int irq; + + irq = pci_irq_vector(pdev, msi_num - 1); + if (irq < 0) + return irq;
pci_endpoint_test_writel(test, PCI_ENDPOINT_TEST_IRQ_TYPE, msix ? PCITEST_IRQ_TYPE_MSIX : @@ -450,11 +454,7 @@ static int pci_endpoint_test_msi_irq(struct pci_endpoint_test *test, if (!val) return -ETIMEDOUT;
- ret = pci_irq_vector(pdev, msi_num - 1); - if (ret < 0) - return ret; - - if (ret != test->last_irq) + if (irq != test->last_irq) return -EIO;
return 0;