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Message-Id: <20250728-luo-pci-v1-19-955b078dd653@kernel.org>
Date: Mon, 28 Jul 2025 01:24:49 -0700
From: Chris Li <chrisl@...nel.org>
To: Bjorn Helgaas <bhelgaas@...gle.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Rafael J. Wysocki" <rafael@...nel.org>, Danilo Krummrich <dakr@...nel.org>,
Len Brown <lenb@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
linux-acpi@...r.kernel.org, David Matlack <dmatlack@...gle.com>,
Pasha Tatashin <tatashin@...gle.com>, Jason Miu <jasonmiu@...gle.com>,
Vipin Sharma <vipinsh@...gle.com>, Saeed Mahameed <saeedm@...dia.com>,
Adithya Jayachandran <ajayachandra@...dia.com>,
Parav Pandit <parav@...dia.com>, William Tu <witu@...dia.com>,
Mike Rapoport <rppt@...nel.org>, Chris Li <chrisl@...nel.org>,
Jason Gunthorpe <jgg@...pe.ca>, Leon Romanovsky <leon@...nel.org>
Subject: [PATCH RFC 19/25] PCI/LUO: Track liveupdate buses
Add the bus state to PCI state, after the devs[] array.
Currently for each bus only save the domain and bus number.
Tested: In QEMU, perform liveupdate prepare. Check dmesg for "collect
liveupdate bus" matching to the liveupdate device's bus.
Signed-off-by: Chris Li <chrisl@...nel.org>
---
drivers/pci/liveupdate.c | 68 ++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 57 insertions(+), 11 deletions(-)
diff --git a/drivers/pci/liveupdate.c b/drivers/pci/liveupdate.c
index ec2d7917441ceb4e3d7cd8becae41ca215cba7c3..bc2c166ef494fd0b38cc05500bf0817c0f50fd95 100644
--- a/drivers/pci/liveupdate.c
+++ b/drivers/pci/liveupdate.c
@@ -16,11 +16,20 @@
#define PCI_SUBSYSTEM_NAME "pci"
static LIST_HEAD(preserved_devices);
+static LIST_HEAD(preserved_buses);
static LIST_HEAD(probe_devices);
+static LIST_HEAD(probe_buses);
+
+struct pci_bus_ser {
+ u16 domain;
+ u8 number;
+};
struct pci_ser {
- u32 count;
+ u32 dev_count;
+ u32 bus_count;
struct pci_dev_ser devs[];
+ /* struct pci_bus_ser buses[] */
};
static void stack_push_buses(struct list_head *stack, struct list_head *buses)
@@ -39,7 +48,7 @@ static void requested_devices_add(struct device *dev, struct list_head *head)
list_move_tail(&dev->lu.lu_next, head);
}
-static int collect_bus_devices_reverse(struct pci_bus *bus, struct list_head *head)
+static int collect_buses_and_devices(struct pci_bus *bus, struct list_head *head)
{
struct pci_dev *pdev;
int count = 0;
@@ -54,6 +63,13 @@ static int collect_bus_devices_reverse(struct pci_bus *bus, struct list_head *he
count++;
}
}
+ if (count || bus->dev.lu.depended) {
+ if (bus->parent)
+ bus->parent->dev.lu.depended = 1;
+ dev_info(&bus->dev, "collect liveupdate bus %s\n",
+ dev_name(&bus->dev));
+ list_move_tail(&bus->dev.lu.lu_next, &preserved_buses);
+ }
return count;
}
@@ -76,9 +92,11 @@ static int build_liveupdate_devices(struct list_head *head)
continue;
}
- count += collect_bus_devices_reverse(bus, head);
- busdev->lu.visited = 0;
+ /* Pop from bus_stack */
list_del_init(&busdev->lu.lu_next);
+
+ count += collect_buses_and_devices(bus, head);
+ busdev->lu.visited = 0;
}
return count;
}
@@ -102,6 +120,16 @@ static void cleanup_liveupdate_devices(struct list_head *head)
dev_cleanup_liveupdate(d);
}
+static void cleanup_liveupdate_buses(struct list_head *head)
+{
+ struct device *b, *n;
+
+ list_for_each_entry_safe(b, n, head, lu.lu_next) {
+ b->lu.depended = 0;
+ list_del_init(&b->lu.lu_next);
+ }
+}
+
static void cleanup_liveupdate_state(struct pci_ser *pci_state)
{
struct folio *folio = virt_to_folio(pci_state);
@@ -165,16 +193,24 @@ static int pci_save_device_state(struct device *dev, struct pci_dev_ser *s)
return 0;
}
+static void pci_save_bus_state(struct pci_bus *bus, struct pci_bus_ser *s)
+{
+ s->number = bus->number;
+ s->domain = pci_domain_nr(bus);
+}
+
static int pci_call_prepare(struct pci_ser *pci_state,
struct list_head *devices)
{
- struct pci_dev_ser *pdev_state_current = pci_state->devs;
+ struct pci_dev_ser *dev_state = pci_state->devs;
+ struct pci_bus_ser *bus_state = (struct pci_bus_ser *)
+ (dev_state + pci_state->dev_count);
struct device *dev, *next;
int ret;
char *reason;
list_for_each_entry_safe(dev, next, devices, lu.lu_next) {
- struct pci_dev_ser *s = pdev_state_current++;
+ struct pci_dev_ser *s = dev_state++;
if (!dev->driver) {
reason = "no driver";
@@ -200,6 +236,8 @@ static int pci_call_prepare(struct pci_ser *pci_state,
}
list_move_tail(&dev->lu.lu_next, &preserved_devices);
}
+ list_for_each_entry(dev, &preserved_buses, lu.lu_next)
+ pci_save_bus_state(to_pci_bus(dev), bus_state++);
return 0;
cancel:
@@ -213,8 +251,10 @@ static int __pci_liveupdate_prepare(void *arg, u64 *data)
LIST_HEAD(requested_devices);
struct pci_ser *pci_state;
int ret;
- int count = build_liveupdate_devices(&requested_devices);
- int size = sizeof(*pci_state) + sizeof(pci_state->devs[0]) * count;
+ int devcnt = build_liveupdate_devices(&requested_devices);
+ int buscnt = list_count_nodes(&preserved_buses);
+ int size = sizeof(*pci_state) + sizeof(pci_state->devs[0]) * devcnt
+ + sizeof(struct pci_bus_ser) * buscnt;
int order = get_order(size);
struct folio *folio;
@@ -225,7 +265,8 @@ static int __pci_liveupdate_prepare(void *arg, u64 *data)
}
pci_state = folio_address(folio);
- pci_state->count = count;
+ pci_state->dev_count = devcnt;
+ pci_state->bus_count = buscnt;
ret = kho_preserve_folio(folio);
if (ret) {
@@ -247,6 +288,7 @@ static int __pci_liveupdate_prepare(void *arg, u64 *data)
folio_put(folio);
cleanup_device:
cleanup_liveupdate_devices(&requested_devices);
+ cleanup_liveupdate_buses(&preserved_buses);
return ret;
}
@@ -336,6 +378,7 @@ static void pci_liveupdate_cancel(void *arg, u64 data)
down_write(&pci_bus_sem);
pci_call_cancel(pci_state);
+ cleanup_liveupdate_buses(&preserved_buses);
cleanup_liveupdate_state(pci_state);
up_write(&pci_bus_sem);
@@ -349,6 +392,7 @@ static void pci_liveupdate_finish(void *arg, u64 data)
pr_info("finish data[%llx]\n", data);
pci_call_finish(&probe_devices);
cleanup_liveupdate_devices(&probe_devices);
+ cleanup_liveupdate_buses(&probe_buses);
cleanup_liveupdate_state(pci_state);
}
@@ -408,14 +452,16 @@ static void pci_dev_do_restore(struct pci_dev *dev, struct pci_dev_ser *s)
void pci_liveupdate_restore(struct pci_dev *dev)
{
int path;
+ struct pci_ser *pci_state;
struct pci_dev_ser *s, *end;
if (!liveupdate_state_updated())
return;
path = pci_get_device_path(dev);
- s = pci_state_get()->devs;
- end = s + pci_state_get()->count;
+ pci_state = pci_state_get();
+ s = pci_state->devs;
+ end = s + pci_state->dev_count;
for (; s < end; s++)
if (s->path == path)
return pci_dev_do_restore(dev, s);
--
2.50.1.487.gc89ff58d15-goog
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