From ecaa4902439298f6b0e29f47424a86b310a9ff4f Mon Sep 17 00:00:00 2001

From: D Scott Phillips <scott@os.amperecomputing.com>

Date: Thu, 30 Mar 2023 17:30:54 +0300

Subject: [PATCH] xhci: also avoid the XHCI_ZERO_64B_REGS quirk with a

 passthrough iommu

Git-commit: ecaa4902439298f6b0e29f47424a86b310a9ff4f

References: git-fixes

Patch-mainline: v6.3-rc6

Previously the quirk was skipped when no iommu was present. The same

rationale for skipping the quirk also applies in the iommu.passthrough=1

case.

Skip applying the XHCI_ZERO_64B_REGS quirk if the device's iommu domain is

passthrough.

Fixes: 12de0a35c996 ("xhci: Add quirk to zero 64bit registers on Renesas PCIe controllers")

Cc: stable <stable@kernel.org>

Signed-off-by: D Scott Phillips <scott@os.amperecomputing.com>

Acked-by: Marc Zyngier <maz@kernel.org>

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>

Link: https://lore.kernel.org/r/20230330143056.1390020-2-mathias.nyman@linux.intel.com

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Oliver Neukum <oneukum@suse.com>

---

 drivers/usb/host/xhci.c |    6 +++++-

 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/usb/host/xhci.c

+++ b/drivers/usb/host/xhci.c

@@ -21,6 +21,7 @@

  */

 #include <linux/pci.h>

+#include <linux/iommu.h>

 #include <linux/iopoll.h>

 #include <linux/irq.h>

 #include <linux/log2.h>

@@ -237,6 +238,7 @@ int xhci_reset(struct xhci_hcd *xhci)

 static void xhci_zero_64b_regs(struct xhci_hcd *xhci)

 {

 	struct device *dev = xhci_to_hcd(xhci)->self.sysdev;

+	struct iommu_domain *domain;

 	int err, i;

 	u64 val;

@@ -254,7 +256,9 @@ static void xhci_zero_64b_regs(struct xh

 	 * an iommu. Doing anything when there is no iommu is definitely

 	 * unsafe...

 	 */

-	if (!(xhci->quirks & XHCI_ZERO_64B_REGS) || !dev->iommu_group)

+	domain = iommu_get_domain_for_dev(dev);

+	if (!(xhci->quirks & XHCI_ZERO_64B_REGS) || !dev->iommu_group ||

+			domain->type == IOMMU_DOMAIN_IDENTITY)

 		return;

 	xhci_info(xhci, "Zeroing 64bit base registers, expecting fault\n");