Merge branch 'remotes/lorenzo/pci/hv'
- Add hibernation support for Hyper-V virtual PCI devices (Dexuan Cui)
- Track Hyper-V pci_protocol_version per-hbus, not globally (Dexuan Cui)
- Avoid kmemleak false positive on hv hbus buffer (Dexuan Cui)
* remotes/lorenzo/pci/hv:
PCI: hv: Avoid a kmemleak false positive caused by the hbus buffer
PCI: hv: Change pci_protocol_version to per-hbus
PCI: hv: Add hibernation support
PCI: hv: Reorganize the code in preparation of hibernation
diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index ad40e84..9977abf 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -76,11 +76,6 @@ static enum pci_protocol_version_t pci_protocol_versions[] = {
PCI_PROTOCOL_VERSION_1_1,
};
-/*
- * Protocol version negotiated by hv_pci_protocol_negotiation().
- */
-static enum pci_protocol_version_t pci_protocol_version;
-
#define PCI_CONFIG_MMIO_LENGTH 0x2000
#define CFG_PAGE_OFFSET 0x1000
#define CFG_PAGE_SIZE (PCI_CONFIG_MMIO_LENGTH - CFG_PAGE_OFFSET)
@@ -455,12 +450,15 @@ enum hv_pcibus_state {
hv_pcibus_init = 0,
hv_pcibus_probed,
hv_pcibus_installed,
+ hv_pcibus_removing,
hv_pcibus_removed,
hv_pcibus_maximum
};
struct hv_pcibus_device {
struct pci_sysdata sysdata;
+ /* Protocol version negotiated with the host */
+ enum pci_protocol_version_t protocol_version;
enum hv_pcibus_state state;
refcount_t remove_lock;
struct hv_device *hdev;
@@ -1224,7 +1222,7 @@ static void hv_irq_unmask(struct irq_data *data)
* negative effect (yet?).
*/
- if (pci_protocol_version >= PCI_PROTOCOL_VERSION_1_2) {
+ if (hbus->protocol_version >= PCI_PROTOCOL_VERSION_1_2) {
/*
* PCI_PROTOCOL_VERSION_1_2 supports the VP_SET version of the
* HVCALL_RETARGET_INTERRUPT hypercall, which also coincides
@@ -1394,7 +1392,7 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
ctxt.pci_pkt.completion_func = hv_pci_compose_compl;
ctxt.pci_pkt.compl_ctxt = ∁
- switch (pci_protocol_version) {
+ switch (hbus->protocol_version) {
case PCI_PROTOCOL_VERSION_1_1:
size = hv_compose_msi_req_v1(&ctxt.int_pkts.v1,
dest,
@@ -1681,6 +1679,23 @@ static void prepopulate_bars(struct hv_pcibus_device *hbus)
spin_lock_irqsave(&hbus->device_list_lock, flags);
+ /*
+ * Clear the memory enable bit, in case it's already set. This occurs
+ * in the suspend path of hibernation, where the device is suspended,
+ * resumed and suspended again: see hibernation_snapshot() and
+ * hibernation_platform_enter().
+ *
+ * If the memory enable bit is already set, Hyper-V sliently ignores
+ * the below BAR updates, and the related PCI device driver can not
+ * work, because reading from the device register(s) always returns
+ * 0xFFFFFFFF.
+ */
+ list_for_each_entry(hpdev, &hbus->children, list_entry) {
+ _hv_pcifront_read_config(hpdev, PCI_COMMAND, 2, &command);
+ command &= ~PCI_COMMAND_MEMORY;
+ _hv_pcifront_write_config(hpdev, PCI_COMMAND, 2, command);
+ }
+
/* Pick addresses for the BARs. */
do {
list_for_each_entry(hpdev, &hbus->children, list_entry) {
@@ -2107,6 +2122,12 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
unsigned long flags;
bool pending_dr;
+ if (hbus->state == hv_pcibus_removing) {
+ dev_info(&hbus->hdev->device,
+ "PCI VMBus BUS_RELATIONS: ignored\n");
+ return;
+ }
+
dr_wrk = kzalloc(sizeof(*dr_wrk), GFP_NOWAIT);
if (!dr_wrk)
return;
@@ -2223,11 +2244,19 @@ static void hv_eject_device_work(struct work_struct *work)
*/
static void hv_pci_eject_device(struct hv_pci_dev *hpdev)
{
+ struct hv_pcibus_device *hbus = hpdev->hbus;
+ struct hv_device *hdev = hbus->hdev;
+
+ if (hbus->state == hv_pcibus_removing) {
+ dev_info(&hdev->device, "PCI VMBus EJECT: ignored\n");
+ return;
+ }
+
hpdev->state = hv_pcichild_ejecting;
get_pcichild(hpdev);
INIT_WORK(&hpdev->wrk, hv_eject_device_work);
- get_hvpcibus(hpdev->hbus);
- queue_work(hpdev->hbus->wq, &hpdev->wrk);
+ get_hvpcibus(hbus);
+ queue_work(hbus->wq, &hpdev->wrk);
}
/**
@@ -2379,8 +2408,11 @@ static void hv_pci_onchannelcallback(void *context)
* failing if the host doesn't support the necessary protocol
* level.
*/
-static int hv_pci_protocol_negotiation(struct hv_device *hdev)
+static int hv_pci_protocol_negotiation(struct hv_device *hdev,
+ enum pci_protocol_version_t version[],
+ int num_version)
{
+ struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
struct pci_version_request *version_req;
struct hv_pci_compl comp_pkt;
struct pci_packet *pkt;
@@ -2403,8 +2435,8 @@ static int hv_pci_protocol_negotiation(struct hv_device *hdev)
version_req = (struct pci_version_request *)&pkt->message;
version_req->message_type.type = PCI_QUERY_PROTOCOL_VERSION;
- for (i = 0; i < ARRAY_SIZE(pci_protocol_versions); i++) {
- version_req->protocol_version = pci_protocol_versions[i];
+ for (i = 0; i < num_version; i++) {
+ version_req->protocol_version = version[i];
ret = vmbus_sendpacket(hdev->channel, version_req,
sizeof(struct pci_version_request),
(unsigned long)pkt, VM_PKT_DATA_INBAND,
@@ -2420,10 +2452,10 @@ static int hv_pci_protocol_negotiation(struct hv_device *hdev)
}
if (comp_pkt.completion_status >= 0) {
- pci_protocol_version = pci_protocol_versions[i];
+ hbus->protocol_version = version[i];
dev_info(&hdev->device,
"PCI VMBus probing: Using version %#x\n",
- pci_protocol_version);
+ hbus->protocol_version);
goto exit;
}
@@ -2707,7 +2739,7 @@ static int hv_send_resources_allocated(struct hv_device *hdev)
u32 wslot;
int ret;
- size_res = (pci_protocol_version < PCI_PROTOCOL_VERSION_1_2)
+ size_res = (hbus->protocol_version < PCI_PROTOCOL_VERSION_1_2)
? sizeof(*res_assigned) : sizeof(*res_assigned2);
pkt = kmalloc(sizeof(*pkt) + size_res, GFP_KERNEL);
@@ -2726,7 +2758,7 @@ static int hv_send_resources_allocated(struct hv_device *hdev)
pkt->completion_func = hv_pci_generic_compl;
pkt->compl_ctxt = &comp_pkt;
- if (pci_protocol_version < PCI_PROTOCOL_VERSION_1_2) {
+ if (hbus->protocol_version < PCI_PROTOCOL_VERSION_1_2) {
res_assigned =
(struct pci_resources_assigned *)&pkt->message;
res_assigned->message_type.type =
@@ -2870,9 +2902,27 @@ static int hv_pci_probe(struct hv_device *hdev,
* hv_pcibus_device contains the hypercall arguments for retargeting in
* hv_irq_unmask(). Those must not cross a page boundary.
*/
- BUILD_BUG_ON(sizeof(*hbus) > PAGE_SIZE);
+ BUILD_BUG_ON(sizeof(*hbus) > HV_HYP_PAGE_SIZE);
- hbus = (struct hv_pcibus_device *)get_zeroed_page(GFP_KERNEL);
+ /*
+ * With the recent 59bb47985c1d ("mm, sl[aou]b: guarantee natural
+ * alignment for kmalloc(power-of-two)"), kzalloc() is able to allocate
+ * a 4KB buffer that is guaranteed to be 4KB-aligned. Here the size and
+ * alignment of hbus is important because hbus's field
+ * retarget_msi_interrupt_params must not cross a 4KB page boundary.
+ *
+ * Here we prefer kzalloc to get_zeroed_page(), because a buffer
+ * allocated by the latter is not tracked and scanned by kmemleak, and
+ * hence kmemleak reports the pointer contained in the hbus buffer
+ * (i.e. the hpdev struct, which is created in new_pcichild_device() and
+ * is tracked by hbus->children) as memory leak (false positive).
+ *
+ * If the kernel doesn't have 59bb47985c1d, get_zeroed_page() *must* be
+ * used to allocate the hbus buffer and we can avoid the kmemleak false
+ * positive by using kmemleak_alloc() and kmemleak_free() to ask
+ * kmemleak to track and scan the hbus buffer.
+ */
+ hbus = (struct hv_pcibus_device *)kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
if (!hbus)
return -ENOMEM;
hbus->state = hv_pcibus_init;
@@ -2930,7 +2980,8 @@ static int hv_pci_probe(struct hv_device *hdev,
hv_set_drvdata(hdev, hbus);
- ret = hv_pci_protocol_negotiation(hdev);
+ ret = hv_pci_protocol_negotiation(hdev, pci_protocol_versions,
+ ARRAY_SIZE(pci_protocol_versions));
if (ret)
goto close;
@@ -3011,7 +3062,7 @@ static int hv_pci_probe(struct hv_device *hdev,
return ret;
}
-static void hv_pci_bus_exit(struct hv_device *hdev)
+static int hv_pci_bus_exit(struct hv_device *hdev, bool hibernating)
{
struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
struct {
@@ -3027,16 +3078,20 @@ static void hv_pci_bus_exit(struct hv_device *hdev)
* access the per-channel ringbuffer any longer.
*/
if (hdev->channel->rescind)
- return;
+ return 0;
- /* Delete any children which might still exist. */
- memset(&relations, 0, sizeof(relations));
- hv_pci_devices_present(hbus, &relations);
+ if (!hibernating) {
+ /* Delete any children which might still exist. */
+ memset(&relations, 0, sizeof(relations));
+ hv_pci_devices_present(hbus, &relations);
+ }
ret = hv_send_resources_released(hdev);
- if (ret)
+ if (ret) {
dev_err(&hdev->device,
"Couldn't send resources released packet(s)\n");
+ return ret;
+ }
memset(&pkt.teardown_packet, 0, sizeof(pkt.teardown_packet));
init_completion(&comp_pkt.host_event);
@@ -3049,8 +3104,13 @@ static void hv_pci_bus_exit(struct hv_device *hdev)
(unsigned long)&pkt.teardown_packet,
VM_PKT_DATA_INBAND,
VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
- if (!ret)
- wait_for_completion_timeout(&comp_pkt.host_event, 10 * HZ);
+ if (ret)
+ return ret;
+
+ if (wait_for_completion_timeout(&comp_pkt.host_event, 10 * HZ) == 0)
+ return -ETIMEDOUT;
+
+ return 0;
}
/**
@@ -3062,6 +3122,7 @@ static void hv_pci_bus_exit(struct hv_device *hdev)
static int hv_pci_remove(struct hv_device *hdev)
{
struct hv_pcibus_device *hbus;
+ int ret;
hbus = hv_get_drvdata(hdev);
if (hbus->state == hv_pcibus_installed) {
@@ -3074,7 +3135,7 @@ static int hv_pci_remove(struct hv_device *hdev)
hbus->state = hv_pcibus_removed;
}
- hv_pci_bus_exit(hdev);
+ ret = hv_pci_bus_exit(hdev, false);
vmbus_close(hdev->channel);
@@ -3090,10 +3151,97 @@ static int hv_pci_remove(struct hv_device *hdev)
hv_put_dom_num(hbus->sysdata.domain);
- free_page((unsigned long)hbus);
+ kfree(hbus);
+ return ret;
+}
+
+static int hv_pci_suspend(struct hv_device *hdev)
+{
+ struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
+ enum hv_pcibus_state old_state;
+ int ret;
+
+ /*
+ * hv_pci_suspend() must make sure there are no pending work items
+ * before calling vmbus_close(), since it runs in a process context
+ * as a callback in dpm_suspend(). When it starts to run, the channel
+ * callback hv_pci_onchannelcallback(), which runs in a tasklet
+ * context, can be still running concurrently and scheduling new work
+ * items onto hbus->wq in hv_pci_devices_present() and
+ * hv_pci_eject_device(), and the work item handlers can access the
+ * vmbus channel, which can be being closed by hv_pci_suspend(), e.g.
+ * the work item handler pci_devices_present_work() ->
+ * new_pcichild_device() writes to the vmbus channel.
+ *
+ * To eliminate the race, hv_pci_suspend() disables the channel
+ * callback tasklet, sets hbus->state to hv_pcibus_removing, and
+ * re-enables the tasklet. This way, when hv_pci_suspend() proceeds,
+ * it knows that no new work item can be scheduled, and then it flushes
+ * hbus->wq and safely closes the vmbus channel.
+ */
+ tasklet_disable(&hdev->channel->callback_event);
+
+ /* Change the hbus state to prevent new work items. */
+ old_state = hbus->state;
+ if (hbus->state == hv_pcibus_installed)
+ hbus->state = hv_pcibus_removing;
+
+ tasklet_enable(&hdev->channel->callback_event);
+
+ if (old_state != hv_pcibus_installed)
+ return -EINVAL;
+
+ flush_workqueue(hbus->wq);
+
+ ret = hv_pci_bus_exit(hdev, true);
+ if (ret)
+ return ret;
+
+ vmbus_close(hdev->channel);
+
return 0;
}
+static int hv_pci_resume(struct hv_device *hdev)
+{
+ struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
+ enum pci_protocol_version_t version[1];
+ int ret;
+
+ hbus->state = hv_pcibus_init;
+
+ ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0,
+ hv_pci_onchannelcallback, hbus);
+ if (ret)
+ return ret;
+
+ /* Only use the version that was in use before hibernation. */
+ version[0] = hbus->protocol_version;
+ ret = hv_pci_protocol_negotiation(hdev, version, 1);
+ if (ret)
+ goto out;
+
+ ret = hv_pci_query_relations(hdev);
+ if (ret)
+ goto out;
+
+ ret = hv_pci_enter_d0(hdev);
+ if (ret)
+ goto out;
+
+ ret = hv_send_resources_allocated(hdev);
+ if (ret)
+ goto out;
+
+ prepopulate_bars(hbus);
+
+ hbus->state = hv_pcibus_installed;
+ return 0;
+out:
+ vmbus_close(hdev->channel);
+ return ret;
+}
+
static const struct hv_vmbus_device_id hv_pci_id_table[] = {
/* PCI Pass-through Class ID */
/* 44C4F61D-4444-4400-9D52-802E27EDE19F */
@@ -3108,6 +3256,8 @@ static struct hv_driver hv_pci_drv = {
.id_table = hv_pci_id_table,
.probe = hv_pci_probe,
.remove = hv_pci_remove,
+ .suspend = hv_pci_suspend,
+ .resume = hv_pci_resume,
};
static void __exit exit_hv_pci_drv(void)
