PCI: vmd: Disable MSI remapping after suspend

MSI remapping is disabled by VMD driver for Intel's Icelake and
newer systems in order to improve performance by setting
VMCONFIG_MSI_REMAP. By design VMCONFIG_MSI_REMAP register is cleared
by firmware during boot. The same register gets cleared when system
is put in S3 power state. VMD driver needs to set this register again
in order to avoid interrupt issues with devices behind VMD if MSI
remapping was disabled before.

Link: https://lore.kernel.org/r/[email protected]
Fixes: ee81ee8 ("PCI: vmd: Disable MSI-X remapping when possible")
Signed-off-by: Nirmal Patel <[email protected]>
Signed-off-by: Lorenzo Pieralisi <[email protected]>
Reviewed-by: Francisco Munoz <[email protected]>

Author: Nirmal Patel

drivers/pci/controller/vmd.c

@@ -980,6 +980,11 @@ static int vmd_resume(struct device *dev)
 	struct vmd_dev *vmd = pci_get_drvdata(pdev);
 	int err, i;
 
+       if (vmd->irq_domain)
+               vmd_set_msi_remapping(vmd, true);
+       else
+               vmd_set_msi_remapping(vmd, false);
+
 	for (i = 0; i < vmd->msix_count; i++) {
 		err = devm_request_irq(dev, vmd->irqs[i].virq,
 				       vmd_irq, IRQF_NO_THREAD,