linux-kernel - [RFC PATCH 17/21] vfio/pci: Disable interrupts before going live update kexec

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Message-ID: <20251018000713.677779-18-vipinsh@google.com>
Date: Fri, 17 Oct 2025 17:07:09 -0700
From: Vipin Sharma <vipinsh@...gle.com>
To: bhelgaas@...gle.com, alex.williamson@...hat.com, pasha.tatashin@...een.com, 
	dmatlack@...gle.com, jgg@...pe.ca, graf@...zon.com
Cc: pratyush@...nel.org, gregkh@...uxfoundation.org, chrisl@...nel.org, 
	rppt@...nel.org, skhawaja@...gle.com, parav@...dia.com, saeedm@...dia.com, 
	kevin.tian@...el.com, jrhilke@...gle.com, david@...hat.com, 
	jgowans@...zon.com, dwmw2@...radead.org, epetron@...zon.de, 
	junaids@...gle.com, linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org, 
	kvm@...r.kernel.org, linux-kselftest@...r.kernel.org, 
	Vipin Sharma <vipinsh@...gle.com>
Subject: [RFC PATCH 17/21] vfio/pci: Disable interrupts before going live
 update kexec

Disable VFIO interrupts configured on device during live update
freeze callback. As there is no way for those interrupts to be handled
during kexec, better stop the interrupts and let userspace reconfigure
them after kexec.

Signed-off-by: Vipin Sharma <vipinsh@...gle.com>
---
 drivers/vfio/pci/vfio_pci_liveupdate.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/vfio/pci/vfio_pci_liveupdate.c b/drivers/vfio/pci/vfio_pci_liveupdate.c
index caef023d007a..5d786ace6bde 100644
--- a/drivers/vfio/pci/vfio_pci_liveupdate.c
+++ b/drivers/vfio/pci/vfio_pci_liveupdate.c
@@ -248,6 +248,22 @@ static int vfio_pci_liveupdate_prepare(struct liveupdate_file_handler *handler,
 	return err;
 }
 
+static int vfio_pci_liveupdate_freeze(struct liveupdate_file_handler *handler,
+				      struct file *file, u64 *data)
+{
+	struct vfio_pci_core_device *vdev;
+	struct vfio_device *device;
+
+	device = vfio_device_from_file(file);
+	vdev = container_of(device, struct vfio_pci_core_device, vdev);
+
+	guard(mutex)(&vdev->igate);
+	if (vdev->irq_type == VFIO_PCI_NUM_IRQS)
+		return 0;
+	return vfio_pci_set_irqs_ioctl(vdev, VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER,
+				       vdev->irq_type, 0, 0, NULL);
+}
+
 static void vfio_pci_liveupdate_cancel(struct liveupdate_file_handler *handler,
 				       struct file *file, u64 data)
 {
@@ -403,6 +419,7 @@ static bool vfio_pci_liveupdate_can_preserve(struct liveupdate_file_handler *han
 
 static const struct liveupdate_file_ops vfio_pci_luo_fops = {
 	.prepare = vfio_pci_liveupdate_prepare,
+	.freeze = vfio_pci_liveupdate_freeze,
 	.cancel = vfio_pci_liveupdate_cancel,
 	.finish = vfio_pci_liveupdate_finish,
 	.retrieve = vfio_pci_liveupdate_retrieve,
-- 
2.51.0.858.gf9c4a03a3a-goog