[PATCH 1/1][SRU][K] PCI: vmd: Disable MSI remapping after suspend

[AceLan Kao]

From: Nirmal Patel <nirmal.patel at linux.intel.com>

BugLink: https://launchpad.net/bugs/1996048

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/20221109142652.450998-1-nirmal.patel@linux.intel.com
Fixes: ee81ee84f873 ("PCI: vmd: Disable MSI-X remapping when possible")
Signed-off-by: Nirmal Patel <nirmal.patel at linux.intel.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi at kernel.org>
Reviewed-by: Francisco Munoz <francisco.munoz.ruiz at linux.intel.com>
(cherry picked from commit d899aa668498c07ff217b666ae9712990306e682)
Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao at canonical.com>
---
 drivers/pci/controller/vmd.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index 94a14a3d7e55..de561f170d26 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -981,6 +981,11 @@ 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,
-- 
2.34.1