FAILED: patch "[PATCH] vfio/pci: Latch disable_idle_d3 per device" failed to apply to 6.1-stable tree

FAILED: patch "[PATCH] vfio/pci: Latch disable_idle_d3 per device" failed to apply to 6.1-stable tree

[gregkh]

The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 4575e9aac5336d1365138c0284773bf8da4b1fa3
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026071301-corned-default-6f79@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 4575e9aac5336d1365138c0284773bf8da4b1fa3 Mon Sep 17 00:00:00 2001
From: Alex Williamson <alex.williamson@nvidia.com>
Date: Mon, 15 Jun 2026 13:12:29 -0600
Subject: [PATCH] vfio/pci: Latch disable_idle_d3 per device

When disable_idle_d3 was introduced in vfio-pci, it directly manipulated
the device power state with pci_set_power_state().  There were no
refcounts to maintain or balanced operations, we could unconditionally
bring the device to D0 and conditionally move it to D3hot.  Therefore
the module parameter was made writable.

Later, in commit c61302aa48f7 ("vfio/pci: Move module parameters to
vfio_pci.c"), as part of the vfio-pci-core split, the writable aspect
of the module parameter was nullified.  The parameter value could still
be changed through sysfs, but the vfio-pci driver latched the values
into vfio-pci-core globals at module init.  Loading the vfio-pci module,
or unloading and reloading, with non-default or different values could
change the globals relative to existing devices bound to vfio-pci
variant drivers.

Runtime PM was introduced in commit 7ab5e10eda02 ("vfio/pci: Move the
unused device into low power state with runtime PM"), which marks the
point where power states became refcounted.  PM get and put operations
need to be balanced, but the same module operations noted above can
change the global variables relative to those devices already bound to
vfio-pci variant drivers.  This introduces a window where PM operations
can now become unbalanced.

To resolve this with a narrow footprint for stable backports, the
disable_idle_d3 flag is latched into the vfio_pci_core_device at the
time of initialization, such that the device always operates with a
consistent value.

NB. vfio_pci_dev_set_try_reset() now unconditionally raises the
runtime PM usage count around bus reset to account for disable_idle_d3
becoming a per-device rather than global flag.  When this flag is set,
the additional get/put pair is harmless and allows continued use of the
shared vfio_pci_dev_set_pm_runtime_get() helper.

Fixes: 7ab5e10eda02 ("vfio/pci: Move the unused device into low power state with runtime PM")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Alex Williamson <alex.williamson@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20260615191241.688297-2-alex.williamson@nvidia.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index a28f1e99362c..f8d1755de2ce 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -538,7 +538,7 @@ int vfio_pci_core_enable(struct vfio_pci_core_device *vdev)
 	u16 cmd;
 	u8 msix_pos;
 
-	if (!disable_idle_d3) {
+	if (!vdev->disable_idle_d3) {
 		ret = pm_runtime_resume_and_get(&pdev->dev);
 		if (ret < 0)
 			return ret;
@@ -617,7 +617,7 @@ int vfio_pci_core_enable(struct vfio_pci_core_device *vdev)
 out_disable_device:
 	pci_disable_device(pdev);
 out_power:
-	if (!disable_idle_d3)
+	if (!vdev->disable_idle_d3)
 		pm_runtime_put(&pdev->dev);
 	return ret;
 }
@@ -753,7 +753,7 @@ void vfio_pci_core_disable(struct vfio_pci_core_device *vdev)
 	vfio_pci_dev_set_try_reset(vdev->vdev.dev_set);
 
 	/* Put the pm-runtime usage counter acquired during enable */
-	if (!disable_idle_d3)
+	if (!vdev->disable_idle_d3)
 		pm_runtime_put(&pdev->dev);
 }
 EXPORT_SYMBOL_GPL(vfio_pci_core_disable);
@@ -2144,6 +2144,8 @@ int vfio_pci_core_init_dev(struct vfio_device *core_vdev)
 	init_rwsem(&vdev->memory_lock);
 	xa_init(&vdev->ctx);
 
+	vdev->disable_idle_d3 = disable_idle_d3;
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(vfio_pci_core_init_dev);
@@ -2239,7 +2241,7 @@ int vfio_pci_core_register_device(struct vfio_pci_core_device *vdev)
 
 	dev->driver->pm = &vfio_pci_core_pm_ops;
 	pm_runtime_allow(dev);
-	if (!disable_idle_d3)
+	if (!vdev->disable_idle_d3)
 		pm_runtime_put(dev);
 
 	ret = vfio_register_group_dev(&vdev->vdev);
@@ -2248,7 +2250,7 @@ int vfio_pci_core_register_device(struct vfio_pci_core_device *vdev)
 	return 0;
 
 out_power:
-	if (!disable_idle_d3)
+	if (!vdev->disable_idle_d3)
 		pm_runtime_get_noresume(dev);
 
 	pm_runtime_forbid(dev);
@@ -2267,7 +2269,7 @@ void vfio_pci_core_unregister_device(struct vfio_pci_core_device *vdev)
 	vfio_pci_vf_uninit(vdev);
 	vfio_pci_vga_uninit(vdev);
 
-	if (!disable_idle_d3)
+	if (!vdev->disable_idle_d3)
 		pm_runtime_get_noresume(&vdev->pdev->dev);
 
 	pm_runtime_forbid(&vdev->pdev->dev);
@@ -2599,7 +2601,7 @@ static void vfio_pci_dev_set_try_reset(struct vfio_device_set *dev_set)
 	 * state. Increment the usage count for all the devices in the dev_set
 	 * before reset and decrement the same after reset.
 	 */
-	if (!disable_idle_d3 && vfio_pci_dev_set_pm_runtime_get(dev_set))
+	if (vfio_pci_dev_set_pm_runtime_get(dev_set))
 		return;
 
 	if (!pci_reset_bus(pdev))
@@ -2609,8 +2611,7 @@ static void vfio_pci_dev_set_try_reset(struct vfio_device_set *dev_set)
 		if (reset_done)
 			cur->needs_reset = false;
 
-		if (!disable_idle_d3)
-			pm_runtime_put(&cur->pdev->dev);
+		pm_runtime_put(&cur->pdev->dev);
 	}
 }
 
diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index 5fc6ce4dd786..27aab3fdbb91 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -127,6 +127,7 @@ struct vfio_pci_core_device {
 	bool			needs_pm_restore:1;
 	bool			pm_intx_masked:1;
 	bool			pm_runtime_engaged:1;
+	bool			disable_idle_d3:1;
 	bool			sriov_active;
 	struct pci_saved_state	*pci_saved_state;
 	struct pci_saved_state	*pm_save;

[PATCH 6.1.y 1/3] vfio/pci: Use bitfield for struct vfio_pci_core_device flags

[Sasha Levin]

From: Reinette Chatre <reinette.chatre@intel.com>

[ Upstream commit 9cd0f6d5cbb6fda09aa83beb8146c287a552017e ]

struct vfio_pci_core_device contains eleven boolean flags.
Boolean flags clearly indicate their usage but space usage
starts to be a concern when there are many.

An upcoming change adds another boolean flag to
struct vfio_pci_core_device, thereby increasing the concern
that the boolean flags are consuming unnecessary space.

Transition the boolean flags to use bitfields. On a system that
uses one byte per boolean this reduces the space consumed
by existing flags from 11 bytes to 2 bytes with room for
a few more flags without increasing the structure's size.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/cf34bf0499c889554a8105eeb18cc0ab673005be.1683740667.git.reinette.chatre@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Stable-dep-of: 4575e9aac533 ("vfio/pci: Latch disable_idle_d3 per device")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/vfio_pci_core.h | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index 367fd79226a306..1c56c1df163cca 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -69,17 +69,17 @@ struct vfio_pci_core_device {
 	u16			msix_size;
 	u32			msix_offset;
 	u32			rbar[7];
-	bool			pci_2_3;
-	bool			virq_disabled;
-	bool			reset_works;
-	bool			extended_caps;
-	bool			bardirty;
-	bool			has_vga;
-	bool			needs_reset;
-	bool			nointx;
-	bool			needs_pm_restore;
-	bool			pm_intx_masked;
-	bool			pm_runtime_engaged;
+	bool			pci_2_3:1;
+	bool			virq_disabled:1;
+	bool			reset_works:1;
+	bool			extended_caps:1;
+	bool			bardirty:1;
+	bool			has_vga:1;
+	bool			needs_reset:1;
+	bool			nointx:1;
+	bool			needs_pm_restore:1;
+	bool			pm_intx_masked:1;
+	bool			pm_runtime_engaged:1;
 	struct pci_saved_state	*pci_saved_state;
 	struct pci_saved_state	*pm_save;
 	int			ioeventfds_nr;
-- 
2.53.0

[PATCH 6.1.y 2/3] vfio/pci: Use a private flag to prevent power state change with VFs

[Sasha Levin]

From: Raghavendra Rao Ananta <rananta@google.com>

[ Upstream commit 40ef3edf151e184d021917a5c4c771cc0870844a ]

The current implementation uses pci_num_vf() while holding the
memory_lock to prevent changing the power state of a PF when
VFs are enabled. This creates a lockdep circular dependency
warning because memory_lock is held during device probing.

[  286.997167] ======================================================
[  287.003363] WARNING: possible circular locking dependency detected
[  287.009562] 7.0.0-dbg-DEV #3 Tainted: G S
[  287.015074] ------------------------------------------------------
[  287.021270] vfio_pci_sriov_/18636 is trying to acquire lock:
[  287.026942] ff45bea2294d4968 (&vdev->memory_lock){+.+.}-{4:4}, at:
vfio_pci_core_runtime_resume+0x1f/0xa0
[  287.036530]
[  287.036530] but task is already holding lock:
[  287.042383] ff45bea3a96b8230 (&new_dev_set->lock){+.+.}-{4:4}, at:
vfio_group_fops_unl_ioctl+0x44d/0x7b0
[  287.051879]
[  287.051879] which lock already depends on the new lock.
[  287.051879]
[  287.060070]
[  287.060070] the existing dependency chain (in reverse order) is:
[  287.067568]
[  287.067568] -> #2 (&new_dev_set->lock){+.+.}-{4:4}:
[  287.073941]        __mutex_lock+0x92/0xb80
[  287.078058]        vfio_assign_device_set+0x66/0x1b0
[  287.083042]        vfio_pci_core_register_device+0xd1/0x2a0
[  287.088638]        vfio_pci_probe+0xd2/0x100
[  287.092933]        local_pci_probe_callback+0x4d/0xa0
[  287.098001]        process_scheduled_works+0x2ca/0x680
[  287.103158]        worker_thread+0x1e8/0x2f0
[  287.107452]        kthread+0x10c/0x140
[  287.111230]        ret_from_fork+0x18e/0x360
[  287.115519]        ret_from_fork_asm+0x1a/0x30
[  287.119983]
[  287.119983] -> #1 ((work_completion)(&arg.work)){+.+.}-{0:0}:
[  287.127219]        __flush_work+0x345/0x490
[  287.131429]        pci_device_probe+0x2e3/0x490
[  287.135979]        really_probe+0x1f9/0x4e0
[  287.140180]        __driver_probe_device+0x77/0x100
[  287.145079]        driver_probe_device+0x1e/0x110
[  287.149803]        __device_attach_driver+0xe3/0x170
[  287.154789]        bus_for_each_drv+0x125/0x150
[  287.159346]        __device_attach+0xca/0x1a0
[  287.163720]        device_initial_probe+0x34/0x50
[  287.168445]        pci_bus_add_device+0x6e/0x90
[  287.172995]        pci_iov_add_virtfn+0x3c9/0x3e0
[  287.177719]        sriov_add_vfs+0x2c/0x60
[  287.181838]        sriov_enable+0x306/0x4a0
[  287.186038]        vfio_pci_core_sriov_configure+0x184/0x220
[  287.191715]        sriov_numvfs_store+0xd9/0x1c0
[  287.196351]        kernfs_fop_write_iter+0x13f/0x1d0
[  287.201338]        vfs_write+0x2be/0x3b0
[  287.205286]        ksys_write+0x73/0x100
[  287.209233]        do_syscall_64+0x14d/0x750
[  287.213529]        entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  287.219120]
[  287.219120] -> #0 (&vdev->memory_lock){+.+.}-{4:4}:
[  287.225491]        __lock_acquire+0x14c6/0x2800
[  287.230048]        lock_acquire+0xd3/0x2f0
[  287.234168]        down_write+0x3a/0xc0
[  287.238019]        vfio_pci_core_runtime_resume+0x1f/0xa0
[  287.243436]        __rpm_callback+0x8c/0x310
[  287.247730]        rpm_resume+0x529/0x6f0
[  287.251765]        __pm_runtime_resume+0x68/0x90
[  287.256402]        vfio_pci_core_enable+0x44/0x310
[  287.261216]        vfio_pci_open_device+0x1c/0x80
[  287.265947]        vfio_df_open+0x10f/0x150
[  287.270148]        vfio_group_fops_unl_ioctl+0x4a4/0x7b0
[  287.275476]        __se_sys_ioctl+0x71/0xc0
[  287.279679]        do_syscall_64+0x14d/0x750
[  287.283975]        entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  287.289559]
[  287.289559] other info that might help us debug this:
[  287.289559]
[  287.297582] Chain exists of:
[  287.297582]   &vdev->memory_lock --> (work_completion)(&arg.work)
--> &new_dev_set->lock
[  287.297582]
[  287.310023]  Possible unsafe locking scenario:
[  287.310023]
[  287.315961]        CPU0                    CPU1
[  287.320510]        ----                    ----
[  287.325059]   lock(&new_dev_set->lock);
[  287.328917]
lock((work_completion)(&arg.work));
[  287.336153]                                lock(&new_dev_set->lock);
[  287.342523]   lock(&vdev->memory_lock);
[  287.346382]
[  287.346382]  *** DEADLOCK ***
[  287.346382]
[  287.352315] 2 locks held by vfio_pci_sriov_/18636:
[  287.357125]  #0: ff45bea208ed3e18 (&group->group_lock){+.+.}-{4:4},
at: vfio_group_fops_unl_ioctl+0x3e3/0x7b0
[  287.367048]  #1: ff45bea3a96b8230 (&new_dev_set->lock){+.+.}-{4:4},
at: vfio_group_fops_unl_ioctl+0x44d/0x7b0
[  287.376976]
[  287.376976] stack backtrace:
[  287.381353] CPU: 191 UID: 0 PID: 18636 Comm: vfio_pci_sriov_
Tainted: G S                  7.0.0-dbg-DEV #3 PREEMPTLAZY
[  287.381355] Tainted: [S]=CPU_OUT_OF_SPEC
[  287.381356] Call Trace:
[  287.381357]  <TASK>
[  287.381358]  dump_stack_lvl+0x54/0x70
[  287.381361]  print_circular_bug+0x2e1/0x300
[  287.381363]  check_noncircular+0xf9/0x120
[  287.381364]  ? __lock_acquire+0x5b4/0x2800
[  287.381366]  __lock_acquire+0x14c6/0x2800
[  287.381368]  ? pci_mmcfg_read+0x4f/0x220
[  287.381370]  ? pci_mmcfg_write+0x57/0x220
[  287.381371]  ? lock_acquire+0xd3/0x2f0
[  287.381373]  ? pci_mmcfg_write+0x57/0x220
[  287.381374]  ? lock_release+0xef/0x360
[  287.381376]  ? vfio_pci_core_runtime_resume+0x1f/0xa0
[  287.381377]  lock_acquire+0xd3/0x2f0
[  287.381378]  ? vfio_pci_core_runtime_resume+0x1f/0xa0
[  287.381379]  ? lock_is_held_type+0x76/0x100
[  287.381382]  down_write+0x3a/0xc0
[  287.381382]  ? vfio_pci_core_runtime_resume+0x1f/0xa0
[  287.381383]  vfio_pci_core_runtime_resume+0x1f/0xa0
[  287.381384]  ? __pfx_pci_pm_runtime_resume+0x10/0x10
[  287.381385]  __rpm_callback+0x8c/0x310
[  287.381386]  ? ktime_get_mono_fast_ns+0x3d/0xb0
[  287.381389]  ? __pfx_pci_pm_runtime_resume+0x10/0x10
[  287.381390]  rpm_resume+0x529/0x6f0
[  287.381392]  ? lock_is_held_type+0x76/0x100
[  287.381394]  __pm_runtime_resume+0x68/0x90
[  287.381396]  vfio_pci_core_enable+0x44/0x310
[  287.381398]  vfio_pci_open_device+0x1c/0x80
[  287.381399]  vfio_df_open+0x10f/0x150
[  287.381401]  vfio_group_fops_unl_ioctl+0x4a4/0x7b0
[  287.381402]  __se_sys_ioctl+0x71/0xc0
[  287.381404]  do_syscall_64+0x14d/0x750
[  287.381405]  ? entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  287.381406]  ? trace_irq_disable+0x25/0xd0
[  287.381409]  entry_SYSCALL_64_after_hwframe+0x77/0x7f

Introduce a private flag 'sriov_active' in the vfio_pci_core_device
struct. This  allows the driver to track the SR-IOV power state requirement
without  relying on pci_num_vf() while holding the memory_lock. The lock is
now  only held to set the flag and ensure the device is in D0, after which
pci_enable_sriov() can be called without the lock.

Fixes: f4162eb1e2fc ("vfio/pci: Change the PF power state to D0 before enabling VFs")
Cc: stable@vger.kernel.org
Suggested-by: Jason Gunthorpe <jgg@ziepe.ca>
Suggested-by: Alex Williamson <alex@shazbot.org>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Link: https://lore.kernel.org/r/20260514173449.3282188-1-rananta@google.com
[promote bitfield to plain bool to avoid storage-unit races]
Signed-off-by: Alex Williamson <alex@shazbot.org>
Stable-dep-of: 4575e9aac533 ("vfio/pci: Latch disable_idle_d3 per device")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/vfio/pci/vfio_pci_core.c | 17 ++++++++++++++---
 include/linux/vfio_pci_core.h    |  1 +
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 13c223228c31e0..a8823cc77b998a 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -237,8 +237,11 @@ int vfio_pci_set_power_state(struct vfio_pci_core_device *vdev, pci_power_t stat
 	int ret;
 
 	/* Prevent changing power state for PFs with VFs enabled */
-	if (pci_num_vf(pdev) && state > PCI_D0)
-		return -EBUSY;
+	if (state > PCI_D0) {
+		lockdep_assert_held_write(&vdev->memory_lock);
+		if (vdev->sriov_active)
+			return -EBUSY;
+	}
 
 	if (vdev->needs_pm_restore) {
 		if (pdev->current_state < PCI_D3hot && state >= PCI_D3hot) {
@@ -2270,8 +2273,9 @@ int vfio_pci_core_sriov_configure(struct vfio_pci_core_device *vdev,
 
 		down_write(&vdev->memory_lock);
 		vfio_pci_set_power_state(vdev, PCI_D0);
-		ret = pci_enable_sriov(pdev, nr_virtfn);
+		vdev->sriov_active = true;
 		up_write(&vdev->memory_lock);
+		ret = pci_enable_sriov(pdev, nr_virtfn);
 		if (ret) {
 			pm_runtime_put(&pdev->dev);
 			goto out_del;
@@ -2285,6 +2289,13 @@ int vfio_pci_core_sriov_configure(struct vfio_pci_core_device *vdev,
 	}
 
 out_del:
+	/*
+	 * Avoid taking the memory_lock intentionally. A race with a power
+	 * state transition would at most result in an -EBUSY, leaving the
+	 * device in PCI_D0.
+	 */
+	vdev->sriov_active = false;
+
 	mutex_lock(&vfio_pci_sriov_pfs_mutex);
 	list_del_init(&vdev->sriov_pfs_item);
 out_unlock:
diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index 1c56c1df163cca..cda27d476d8597 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -80,6 +80,7 @@ struct vfio_pci_core_device {
 	bool			needs_pm_restore:1;
 	bool			pm_intx_masked:1;
 	bool			pm_runtime_engaged:1;
+	bool			sriov_active;
 	struct pci_saved_state	*pci_saved_state;
 	struct pci_saved_state	*pm_save;
 	int			ioeventfds_nr;
-- 
2.53.0

[PATCH 6.1.y 3/3] vfio/pci: Latch disable_idle_d3 per device

[Sasha Levin]

From: Alex Williamson <alex.williamson@nvidia.com>

[ Upstream commit 4575e9aac5336d1365138c0284773bf8da4b1fa3 ]

When disable_idle_d3 was introduced in vfio-pci, it directly manipulated
the device power state with pci_set_power_state().  There were no
refcounts to maintain or balanced operations, we could unconditionally
bring the device to D0 and conditionally move it to D3hot.  Therefore
the module parameter was made writable.

Later, in commit c61302aa48f7 ("vfio/pci: Move module parameters to
vfio_pci.c"), as part of the vfio-pci-core split, the writable aspect
of the module parameter was nullified.  The parameter value could still
be changed through sysfs, but the vfio-pci driver latched the values
into vfio-pci-core globals at module init.  Loading the vfio-pci module,
or unloading and reloading, with non-default or different values could
change the globals relative to existing devices bound to vfio-pci
variant drivers.

Runtime PM was introduced in commit 7ab5e10eda02 ("vfio/pci: Move the
unused device into low power state with runtime PM"), which marks the
point where power states became refcounted.  PM get and put operations
need to be balanced, but the same module operations noted above can
change the global variables relative to those devices already bound to
vfio-pci variant drivers.  This introduces a window where PM operations
can now become unbalanced.

To resolve this with a narrow footprint for stable backports, the
disable_idle_d3 flag is latched into the vfio_pci_core_device at the
time of initialization, such that the device always operates with a
consistent value.

NB. vfio_pci_dev_set_try_reset() now unconditionally raises the
runtime PM usage count around bus reset to account for disable_idle_d3
becoming a per-device rather than global flag.  When this flag is set,
the additional get/put pair is harmless and allows continued use of the
shared vfio_pci_dev_set_pm_runtime_get() helper.

Fixes: 7ab5e10eda02 ("vfio/pci: Move the unused device into low power state with runtime PM")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Alex Williamson <alex.williamson@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20260615191241.688297-2-alex.williamson@nvidia.com
Signed-off-by: Alex Williamson <alex@shazbot.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/vfio/pci/vfio_pci_core.c | 19 ++++++++++---------
 include/linux/vfio_pci_core.h    |  1 +
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index a8823cc77b998a..519907bddeffb9 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -472,7 +472,7 @@ int vfio_pci_core_enable(struct vfio_pci_core_device *vdev)
 	u16 cmd;
 	u8 msix_pos;
 
-	if (!disable_idle_d3) {
+	if (!vdev->disable_idle_d3) {
 		ret = pm_runtime_resume_and_get(&pdev->dev);
 		if (ret < 0)
 			return ret;
@@ -547,7 +547,7 @@ int vfio_pci_core_enable(struct vfio_pci_core_device *vdev)
 out_disable_device:
 	pci_disable_device(pdev);
 out_power:
-	if (!disable_idle_d3)
+	if (!vdev->disable_idle_d3)
 		pm_runtime_put(&pdev->dev);
 	return ret;
 }
@@ -674,7 +674,7 @@ void vfio_pci_core_disable(struct vfio_pci_core_device *vdev)
 	vfio_pci_dev_set_try_reset(vdev->vdev.dev_set);
 
 	/* Put the pm-runtime usage counter acquired during enable */
-	if (!disable_idle_d3)
+	if (!vdev->disable_idle_d3)
 		pm_runtime_put(&pdev->dev);
 }
 EXPORT_SYMBOL_GPL(vfio_pci_core_disable);
@@ -2091,6 +2091,8 @@ int vfio_pci_core_init_dev(struct vfio_device *core_vdev)
 	INIT_LIST_HEAD(&vdev->sriov_pfs_item);
 	init_rwsem(&vdev->memory_lock);
 
+	vdev->disable_idle_d3 = disable_idle_d3;
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(vfio_pci_core_init_dev);
@@ -2183,7 +2185,7 @@ int vfio_pci_core_register_device(struct vfio_pci_core_device *vdev)
 
 	dev->driver->pm = &vfio_pci_core_pm_ops;
 	pm_runtime_allow(dev);
-	if (!disable_idle_d3)
+	if (!vdev->disable_idle_d3)
 		pm_runtime_put(dev);
 
 	ret = vfio_register_group_dev(&vdev->vdev);
@@ -2192,7 +2194,7 @@ int vfio_pci_core_register_device(struct vfio_pci_core_device *vdev)
 	return 0;
 
 out_power:
-	if (!disable_idle_d3)
+	if (!vdev->disable_idle_d3)
 		pm_runtime_get_noresume(dev);
 
 	pm_runtime_forbid(dev);
@@ -2211,7 +2213,7 @@ void vfio_pci_core_unregister_device(struct vfio_pci_core_device *vdev)
 	vfio_pci_vf_uninit(vdev);
 	vfio_pci_vga_uninit(vdev);
 
-	if (!disable_idle_d3)
+	if (!vdev->disable_idle_d3)
 		pm_runtime_get_noresume(&vdev->pdev->dev);
 
 	pm_runtime_forbid(&vdev->pdev->dev);
@@ -2526,7 +2528,7 @@ static void vfio_pci_dev_set_try_reset(struct vfio_device_set *dev_set)
 	 * state. Increment the usage count for all the devices in the dev_set
 	 * before reset and decrement the same after reset.
 	 */
-	if (!disable_idle_d3 && vfio_pci_dev_set_pm_runtime_get(dev_set))
+	if (vfio_pci_dev_set_pm_runtime_get(dev_set))
 		return;
 
 	if (!pci_reset_bus(pdev))
@@ -2536,8 +2538,7 @@ static void vfio_pci_dev_set_try_reset(struct vfio_device_set *dev_set)
 		if (reset_done)
 			cur->needs_reset = false;
 
-		if (!disable_idle_d3)
-			pm_runtime_put(&cur->pdev->dev);
+		pm_runtime_put(&cur->pdev->dev);
 	}
 }
 
diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index cda27d476d8597..9197cac4faadb2 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -80,6 +80,7 @@ struct vfio_pci_core_device {
 	bool			needs_pm_restore:1;
 	bool			pm_intx_masked:1;
 	bool			pm_runtime_engaged:1;
+	bool			disable_idle_d3:1;
 	bool			sriov_active;
 	struct pci_saved_state	*pci_saved_state;
 	struct pci_saved_state	*pm_save;
-- 
2.53.0