Drivers: hv: vmbus: Move the code to signal end of message

As part of the effort to separate out architecture specific code, move the
code for signaling end of message.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
K. Y. Srinivasan 2017-01-19 11:51:50 -07:00 committed by Greg Kroah-Hartman
parent 73638cddaa
commit e810e48c0c
3 changed files with 38 additions and 35 deletions

View File

@ -99,6 +99,43 @@ static inline __u64 generate_guest_id(__u64 d_info1, __u64 kernel_version,
return guest_id;
}
/* Free the message slot and signal end-of-message if required */
static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
{
/*
* On crash we're reading some other CPU's message page and we need
* to be careful: this other CPU may already had cleared the header
* and the host may already had delivered some other message there.
* In case we blindly write msg->header.message_type we're going
* to lose it. We can still lose a message of the same type but
* we count on the fact that there can only be one
* CHANNELMSG_UNLOAD_RESPONSE and we don't care about other messages
* on crash.
*/
if (cmpxchg(&msg->header.message_type, old_msg_type,
HVMSG_NONE) != old_msg_type)
return;
/*
* Make sure the write to MessageType (ie set to
* HVMSG_NONE) happens before we read the
* MessagePending and EOMing. Otherwise, the EOMing
* will not deliver any more messages since there is
* no empty slot
*/
mb();
if (msg->header.message_flags.msg_pending) {
/*
* This will cause message queue rescan to
* possibly deliver another msg from the
* hypervisor
*/
wrmsrl(HV_X64_MSR_EOM, 0);
}
}
void hyperv_callback_vector(void);
#ifdef CONFIG_TRACING
#define trace_hyperv_callback_vector hyperv_callback_vector

View File

@ -31,6 +31,7 @@
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/hyperv.h>
#include <asm/mshyperv.h>
#include "hyperv_vmbus.h"

View File

@ -521,41 +521,6 @@ struct vmbus_channel_message_table_entry {
extern struct vmbus_channel_message_table_entry
channel_message_table[CHANNELMSG_COUNT];
/* Free the message slot and signal end-of-message if required */
static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
{
/*
* On crash we're reading some other CPU's message page and we need
* to be careful: this other CPU may already had cleared the header
* and the host may already had delivered some other message there.
* In case we blindly write msg->header.message_type we're going
* to lose it. We can still lose a message of the same type but
* we count on the fact that there can only be one
* CHANNELMSG_UNLOAD_RESPONSE and we don't care about other messages
* on crash.
*/
if (cmpxchg(&msg->header.message_type, old_msg_type,
HVMSG_NONE) != old_msg_type)
return;
/*
* Make sure the write to MessageType (ie set to
* HVMSG_NONE) happens before we read the
* MessagePending and EOMing. Otherwise, the EOMing
* will not deliver any more messages since there is
* no empty slot
*/
mb();
if (msg->header.message_flags.msg_pending) {
/*
* This will cause message queue rescan to
* possibly deliver another msg from the
* hypervisor
*/
wrmsrl(HV_X64_MSR_EOM, 0);
}
}
/* General vmbus interface */