[PATCH 2/2][SRU][J/U/OEM-5.17] PCI: vmd: Revert 2565e5b69c44 ("PCI: vmd: Do not disable MSI-X remapping if interrupt remapping is enabled by IOMMU.")

[Koba Ko]

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

BugLink: https://bugs.launchpad.net/bugs/1976587

Revert 2565e5b69c44 ("PCI: vmd: Do not disable MSI-X remapping if
interrupt remapping is enabled by IOMMU.")

The commit 2565e5b69c44 was added as a workaround to keep MSI-X
remapping enabled if IOMMU enables interrupt remapping. VMD would keep
running in low performance mode. There is no dependency between MSI-X
remapping by VMD and interrupt remapping by IOMMU.

Link: https://lore.kernel.org/r/20220511095707.25403-3-nirmal.patel@linux.intel.com
Signed-off-by: Nirmal Patel <nirmal.patel at linux.intel.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
(cherry picked from commit c94f732e8001a860b42aa740b0a178a29907463c git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git)
Signed-off-by: Koba Ko <koba.ko at canonical.com>
---
 drivers/pci/controller/vmd.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index 5015adc04d191..94a14a3d7e555 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -6,7 +6,6 @@
 
 #include <linux/device.h>
 #include <linux/interrupt.h>
-#include <linux/iommu.h>
 #include <linux/irq.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -813,8 +812,7 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
 	 * acceptable because the guest is usually CPU-limited and MSI
 	 * remapping doesn't become a performance bottleneck.
 	 */
-	if (iommu_capable(vmd->dev->dev.bus, IOMMU_CAP_INTR_REMAP) ||
-	    !(features & VMD_FEAT_CAN_BYPASS_MSI_REMAP) ||
+	if (!(features & VMD_FEAT_CAN_BYPASS_MSI_REMAP) ||
 	    offset[0] || offset[1]) {
 		ret = vmd_alloc_irqs(vmd);
 		if (ret)
-- 
2.34.1