linux_dsm_epyc7002/drivers/hv/hyperv_vmbus.h
Dexuan Cui 37c2578c0c Drivers: hv: vmbus: Offload the handling of channels to two workqueues
vmbus_process_offer() mustn't call channel->sc_creation_callback()
directly for sub-channels, because sc_creation_callback() ->
vmbus_open() may never get the host's response to the
OPEN_CHANNEL message (the host may rescind a channel at any time,
e.g. in the case of hot removing a NIC), and vmbus_onoffer_rescind()
may not wake up the vmbus_open() as it's blocked due to a non-zero
vmbus_connection.offer_in_progress, and finally we have a deadlock.

The above is also true for primary channels, if the related device
drivers use sync probing mode by default.

And, usually the handling of primary channels and sub-channels can
depend on each other, so we should offload them to different
workqueues to avoid possible deadlock, e.g. in sync-probing mode,
NIC1's netvsc_subchan_work() can race with NIC2's netvsc_probe() ->
rtnl_lock(), and causes deadlock: the former gets the rtnl_lock
and waits for all the sub-channels to appear, but the latter
can't get the rtnl_lock and this blocks the handling of sub-channels.

The patch can fix the multiple-NIC deadlock described above for
v3.x kernels (e.g. RHEL 7.x) which don't support async-probing
of devices, and v4.4, v4.9, v4.14 and v4.18 which support async-probing
but don't enable async-probing for Hyper-V drivers (yet).

The patch can also fix the hang issue in sub-channel's handling described
above for all versions of kernels, including v4.19 and v4.20-rc4.

So actually the patch should be applied to all the existing kernels,
not only the kernels that have 8195b1396e.

Fixes: 8195b1396e ("hv_netvsc: fix deadlock on hotplug")
Cc: stable@vger.kernel.org
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-03 08:01:01 +01:00

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C

/*
*
* Copyright (c) 2011, Microsoft Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
* Place - Suite 330, Boston, MA 02111-1307 USA.
*
* Authors:
* Haiyang Zhang <haiyangz@microsoft.com>
* Hank Janssen <hjanssen@microsoft.com>
* K. Y. Srinivasan <kys@microsoft.com>
*
*/
#ifndef _HYPERV_VMBUS_H
#define _HYPERV_VMBUS_H
#include <linux/list.h>
#include <asm/sync_bitops.h>
#include <asm/hyperv-tlfs.h>
#include <linux/atomic.h>
#include <linux/hyperv.h>
#include <linux/interrupt.h>
#include "hv_trace.h"
/*
* Timeout for services such as KVP and fcopy.
*/
#define HV_UTIL_TIMEOUT 30
/*
* Timeout for guest-host handshake for services.
*/
#define HV_UTIL_NEGO_TIMEOUT 55
/* Define synthetic interrupt controller flag constants. */
#define HV_EVENT_FLAGS_COUNT (256 * 8)
#define HV_EVENT_FLAGS_LONG_COUNT (256 / sizeof(unsigned long))
/*
* Timer configuration register.
*/
union hv_timer_config {
u64 as_uint64;
struct {
u64 enable:1;
u64 periodic:1;
u64 lazy:1;
u64 auto_enable:1;
u64 apic_vector:8;
u64 direct_mode:1;
u64 reserved_z0:3;
u64 sintx:4;
u64 reserved_z1:44;
};
};
/* Define the synthetic interrupt controller event flags format. */
union hv_synic_event_flags {
unsigned long flags[HV_EVENT_FLAGS_LONG_COUNT];
};
/* Define SynIC control register. */
union hv_synic_scontrol {
u64 as_uint64;
struct {
u64 enable:1;
u64 reserved:63;
};
};
/* Define synthetic interrupt source. */
union hv_synic_sint {
u64 as_uint64;
struct {
u64 vector:8;
u64 reserved1:8;
u64 masked:1;
u64 auto_eoi:1;
u64 reserved2:46;
};
};
/* Define the format of the SIMP register */
union hv_synic_simp {
u64 as_uint64;
struct {
u64 simp_enabled:1;
u64 preserved:11;
u64 base_simp_gpa:52;
};
};
/* Define the format of the SIEFP register */
union hv_synic_siefp {
u64 as_uint64;
struct {
u64 siefp_enabled:1;
u64 preserved:11;
u64 base_siefp_gpa:52;
};
};
/* Definitions for the monitored notification facility */
union hv_monitor_trigger_group {
u64 as_uint64;
struct {
u32 pending;
u32 armed;
};
};
struct hv_monitor_parameter {
union hv_connection_id connectionid;
u16 flagnumber;
u16 rsvdz;
};
union hv_monitor_trigger_state {
u32 asu32;
struct {
u32 group_enable:4;
u32 rsvdz:28;
};
};
/* struct hv_monitor_page Layout */
/* ------------------------------------------------------ */
/* | 0 | TriggerState (4 bytes) | Rsvd1 (4 bytes) | */
/* | 8 | TriggerGroup[0] | */
/* | 10 | TriggerGroup[1] | */
/* | 18 | TriggerGroup[2] | */
/* | 20 | TriggerGroup[3] | */
/* | 28 | Rsvd2[0] | */
/* | 30 | Rsvd2[1] | */
/* | 38 | Rsvd2[2] | */
/* | 40 | NextCheckTime[0][0] | NextCheckTime[0][1] | */
/* | ... | */
/* | 240 | Latency[0][0..3] | */
/* | 340 | Rsvz3[0] | */
/* | 440 | Parameter[0][0] | */
/* | 448 | Parameter[0][1] | */
/* | ... | */
/* | 840 | Rsvd4[0] | */
/* ------------------------------------------------------ */
struct hv_monitor_page {
union hv_monitor_trigger_state trigger_state;
u32 rsvdz1;
union hv_monitor_trigger_group trigger_group[4];
u64 rsvdz2[3];
s32 next_checktime[4][32];
u16 latency[4][32];
u64 rsvdz3[32];
struct hv_monitor_parameter parameter[4][32];
u8 rsvdz4[1984];
};
#define HV_HYPERCALL_PARAM_ALIGN sizeof(u64)
/* Definition of the hv_post_message hypercall input structure. */
struct hv_input_post_message {
union hv_connection_id connectionid;
u32 reserved;
u32 message_type;
u32 payload_size;
u64 payload[HV_MESSAGE_PAYLOAD_QWORD_COUNT];
};
enum {
VMBUS_MESSAGE_CONNECTION_ID = 1,
VMBUS_MESSAGE_CONNECTION_ID_4 = 4,
VMBUS_MESSAGE_PORT_ID = 1,
VMBUS_EVENT_CONNECTION_ID = 2,
VMBUS_EVENT_PORT_ID = 2,
VMBUS_MONITOR_CONNECTION_ID = 3,
VMBUS_MONITOR_PORT_ID = 3,
VMBUS_MESSAGE_SINT = 2,
};
/*
* Per cpu state for channel handling
*/
struct hv_per_cpu_context {
void *synic_message_page;
void *synic_event_page;
/*
* buffer to post messages to the host.
*/
void *post_msg_page;
/*
* Starting with win8, we can take channel interrupts on any CPU;
* we will manage the tasklet that handles events messages on a per CPU
* basis.
*/
struct tasklet_struct msg_dpc;
/*
* To optimize the mapping of relid to channel, maintain
* per-cpu list of the channels based on their CPU affinity.
*/
struct list_head chan_list;
struct clock_event_device *clk_evt;
};
struct hv_context {
/* We only support running on top of Hyper-V
* So at this point this really can only contain the Hyper-V ID
*/
u64 guestid;
void *tsc_page;
bool synic_initialized;
struct hv_per_cpu_context __percpu *cpu_context;
/*
* To manage allocations in a NUMA node.
* Array indexed by numa node ID.
*/
struct cpumask *hv_numa_map;
};
extern struct hv_context hv_context;
/* Hv Interface */
extern int hv_init(void);
extern int hv_post_message(union hv_connection_id connection_id,
enum hv_message_type message_type,
void *payload, size_t payload_size);
extern int hv_synic_alloc(void);
extern void hv_synic_free(void);
extern int hv_synic_init(unsigned int cpu);
extern int hv_synic_cleanup(unsigned int cpu);
extern void hv_synic_clockevents_cleanup(void);
/* Interface */
int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
struct page *pages, u32 pagecnt);
void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info);
int hv_ringbuffer_write(struct vmbus_channel *channel,
const struct kvec *kv_list, u32 kv_count);
int hv_ringbuffer_read(struct vmbus_channel *channel,
void *buffer, u32 buflen, u32 *buffer_actual_len,
u64 *requestid, bool raw);
/*
* Maximum channels is determined by the size of the interrupt page
* which is PAGE_SIZE. 1/2 of PAGE_SIZE is for send endpoint interrupt
* and the other is receive endpoint interrupt
*/
#define MAX_NUM_CHANNELS ((PAGE_SIZE >> 1) << 3) /* 16348 channels */
/* The value here must be in multiple of 32 */
/* TODO: Need to make this configurable */
#define MAX_NUM_CHANNELS_SUPPORTED 256
enum vmbus_connect_state {
DISCONNECTED,
CONNECTING,
CONNECTED,
DISCONNECTING
};
#define MAX_SIZE_CHANNEL_MESSAGE HV_MESSAGE_PAYLOAD_BYTE_COUNT
struct vmbus_connection {
/*
* CPU on which the initial host contact was made.
*/
int connect_cpu;
u32 msg_conn_id;
atomic_t offer_in_progress;
enum vmbus_connect_state conn_state;
atomic_t next_gpadl_handle;
struct completion unload_event;
/*
* Represents channel interrupts. Each bit position represents a
* channel. When a channel sends an interrupt via VMBUS, it finds its
* bit in the sendInterruptPage, set it and calls Hv to generate a port
* event. The other end receives the port event and parse the
* recvInterruptPage to see which bit is set
*/
void *int_page;
void *send_int_page;
void *recv_int_page;
/*
* 2 pages - 1st page for parent->child notification and 2nd
* is child->parent notification
*/
struct hv_monitor_page *monitor_pages[2];
struct list_head chn_msg_list;
spinlock_t channelmsg_lock;
/* List of channels */
struct list_head chn_list;
struct mutex channel_mutex;
/*
* An offer message is handled first on the work_queue, and then
* is further handled on handle_primary_chan_wq or
* handle_sub_chan_wq.
*/
struct workqueue_struct *work_queue;
struct workqueue_struct *handle_primary_chan_wq;
struct workqueue_struct *handle_sub_chan_wq;
};
struct vmbus_msginfo {
/* Bookkeeping stuff */
struct list_head msglist_entry;
/* The message itself */
unsigned char msg[0];
};
extern struct vmbus_connection vmbus_connection;
static inline void vmbus_send_interrupt(u32 relid)
{
sync_set_bit(relid, vmbus_connection.send_int_page);
}
enum vmbus_message_handler_type {
/* The related handler can sleep. */
VMHT_BLOCKING = 0,
/* The related handler must NOT sleep. */
VMHT_NON_BLOCKING = 1,
};
struct vmbus_channel_message_table_entry {
enum vmbus_channel_message_type message_type;
enum vmbus_message_handler_type handler_type;
void (*message_handler)(struct vmbus_channel_message_header *msg);
};
extern const struct vmbus_channel_message_table_entry
channel_message_table[CHANNELMSG_COUNT];
/* General vmbus interface */
struct hv_device *vmbus_device_create(const uuid_le *type,
const uuid_le *instance,
struct vmbus_channel *channel);
int vmbus_device_register(struct hv_device *child_device_obj);
void vmbus_device_unregister(struct hv_device *device_obj);
int vmbus_add_channel_kobj(struct hv_device *device_obj,
struct vmbus_channel *channel);
struct vmbus_channel *relid2channel(u32 relid);
void vmbus_free_channels(void);
/* Connection interface */
int vmbus_connect(void);
void vmbus_disconnect(void);
int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep);
void vmbus_on_event(unsigned long data);
void vmbus_on_msg_dpc(unsigned long data);
int hv_kvp_init(struct hv_util_service *srv);
void hv_kvp_deinit(void);
void hv_kvp_onchannelcallback(void *context);
int hv_vss_init(struct hv_util_service *srv);
void hv_vss_deinit(void);
void hv_vss_onchannelcallback(void *context);
int hv_fcopy_init(struct hv_util_service *srv);
void hv_fcopy_deinit(void);
void hv_fcopy_onchannelcallback(void *context);
void vmbus_initiate_unload(bool crash);
static inline void hv_poll_channel(struct vmbus_channel *channel,
void (*cb)(void *))
{
if (!channel)
return;
if (in_interrupt() && (channel->target_cpu == smp_processor_id())) {
cb(channel);
return;
}
smp_call_function_single(channel->target_cpu, cb, channel, true);
}
enum hvutil_device_state {
HVUTIL_DEVICE_INIT = 0, /* driver is loaded, waiting for userspace */
HVUTIL_READY, /* userspace is registered */
HVUTIL_HOSTMSG_RECEIVED, /* message from the host was received */
HVUTIL_USERSPACE_REQ, /* request to userspace was sent */
HVUTIL_USERSPACE_RECV, /* reply from userspace was received */
HVUTIL_DEVICE_DYING, /* driver unload is in progress */
};
#endif /* _HYPERV_VMBUS_H */