0001-iwlwifi-avoid-writing-to-MSI-X-page-when-MSI-X-is-no.patch

From cb62c7b33172aa2270608be67b82eb0d2a92195b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
 <marmarek@invisiblethingslab.com>
Date: Sat, 29 Jul 2023 15:31:54 +0200
Subject: [PATCH] iwlwifi: avoid writing to MSI-X page when MSI-X is not
 enabled
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Xen 4.17 crashes the domain on write to MSI-X page. Upcoming fix for
that coincides with re-enabling MSI-X support with HVM, so before
writing, check if MSI-X is enabled.

This is a temporary hack, not really suitable for upstream submission.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
---
 drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c
index fa46dad5fd68..b78539965d59 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c
@@ -9,6 +9,8 @@
 #include "iwl-context-info-gen3.h"
 #include "internal.h"
 #include "fw/dbg.h"
+// HACK
+#include "pcie/internal.h"
 
 #define FW_RESET_TIMEOUT (HZ / 5)
 
@@ -387,7 +389,13 @@ static bool iwl_pcie_set_ltr(struct iwl_trans *trans)
 		return true;
 	}
 
-	if (trans->trans_cfg->device_family == IWL_DEVICE_FAMILY_AX210) {
+	/*
+	 * Xen 4.17 crashes the domain on write to MSI-X page. Upcoming fix for
+	 * that coincides with re-enabling MSI-X support with HVM, so before
+	 * writing, check if MSI-X is enabled
+	 */
+	if (trans->trans_cfg->device_family == IWL_DEVICE_FAMILY_AX210 &&
+		    IWL_TRANS_GET_PCIE_TRANS(trans)->msix_enabled) {
 		/* First clear the interrupt, just in case */
 		iwl_write32(trans, CSR_MSIX_HW_INT_CAUSES_AD,
 			    MSIX_HW_INT_CAUSES_REG_IML);
-- 
2.41.0