[patch V3 01/35] PCI/MSI: Set pci_dev::msi[x]_enabled early

Thomas Gleixner
2021-12-10T22:19:14Z

There are quite some places which retrieve the first MSI descriptor to
evaluate whether the setup is for MSI or MSI-X. That's required because
pci_dev::msi[x]_enabled is only set when the setup completed successfully.

There is no real reason why msi[x]_enabled can't be set at the beginning of
the setup sequence and cleared in case of a failure.

Implement that so the MSI descriptor evaluations can be converted to simple
property queries.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
V3: New patch
---
drivers/pci/msi/msi.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)

--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -421,11 +421,18 @@ static int msi_capability_init(struct pc
struct msi_desc *entry;
int ret;

- pci_msi_set_enable(dev, 0); /* Disable MSI during set up */
+ /*
+ * Disable MSI during setup in the hardware, but mark it enabled
+ * so that setup code can evaluate it.
+ */
+ pci_msi_set_enable(dev, 0);
+ dev->msi_enabled = 1;

entry = msi_setup_entry(dev, nvec, affd);
- if (!entry)
- return -ENOMEM;
+ if (!entry) {
+ ret = -ENOMEM;
+ goto fail;
+ }

/* All MSIs are unmasked by default; mask them all */
pci_msi_mask(entry, msi_multi_mask(entry));
@@ -452,7 +459,6 @@ static int msi_capability_init(struct pc
/* Set MSI enabled bits */
pci_intx_for_msi(dev, 0);
pci_msi_set_enable(dev, 1);
- dev->msi_enabled = 1;

pcibios_free_irq(dev);
dev->irq = entry->irq;
@@ -461,6 +467,8 @@ static int msi_capability_init(struct pc
err:
pci_msi_unmask(entry, msi_multi_mask(entry));
free_msi_irqs(dev);
+fail:
+ dev->msi_enabled = 0;
return ret;
}

@@ -589,6 +597,9 @@ static int msix_capability_init(struct p
pci_msix_clear_and_set_ctrl(dev, 0, PCI_MSIX_FLAGS_MASKALL |
PCI_MSIX_FLAGS_ENABLE);

+ /* Mark it enabled so setup functions can query it */
+ dev->msix_enabled = 1;
+
pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control);
/* Request & Map MSI-X table region */
tsize = msix_table_size(control);
@@ -626,9 +637,8 @@ static int msix_capability_init(struct p

dev->msi_irq_groups = groups;

- /* Set MSI-X enabled bits and unmask the function */
+ /* Disable INTX and unmask MSI-X */
pci_intx_for_msi(dev, 0);
- dev->msix_enabled = 1;
pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);

pcibios_free_irq(dev);
@@ -638,6 +648,7 @@ static int msix_capability_init(struct p
free_msi_irqs(dev);

out_disable:
+ dev->msix_enabled = 0;
pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);

return ret;