linux-kernel - [PATCH] vfio/platform: Fix reset

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Date:   Fri,  3 Mar 2023 12:11:52 +0000
From:   Mostafa Saleh <smostafa@...gle.com>
To:     eric.auger@...hat.com, alex.williamson@...hat.com
Cc:     cohuck@...hat.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, smostafa@...gle.com
Subject: [PATCH] vfio/platform: Fix reset_required behaviour

vfio_platform_device has a flag reset_required that can be set from
module_param or vfio driver which indicates that reset is not a
requirement and it bypasses related checks.

This was introduced and implemented in vfio_platform_probe_common in
"b5add544d67 vfio, platform: make reset driver a requirement by default"

However, vfio_platform_probe_common was removed in
"ac1237912fb vfio/amba: Use the new device life cycle helpers"

And new implementation added in vfio_platform_init_common in
"5f6c7e0831a vfio/platform: Use the new device life cycle helpers"

which causes an error even if vfio-platform.reset_required=0, as it
only guards printing and not the return as before.

This patch fixes this by returning 0 if there is no reset function
for the device and reset_required=0. This is also consistent with
checks in vfio_platform_open_device and vfio_platform_close_device.

Signed-off-by: Mostafa Saleh <smostafa@...gle.com>
---
 drivers/vfio/platform/vfio_platform_common.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index 1a0a238ffa35..7325ff463cf0 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -650,10 +650,13 @@ int vfio_platform_init_common(struct vfio_platform_device *vdev)
 	mutex_init(&vdev->igate);
 
 	ret = vfio_platform_get_reset(vdev);
-	if (ret && vdev->reset_required)
+	if (ret && vdev->reset_required) {
 		dev_err(dev, "No reset function found for device %s\n",
 			vdev->name);
-	return ret;
+		return ret;
+	}
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(vfio_platform_init_common);
 
-- 
2.40.0.rc0.216.gc4246ad0f0-goog