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rus_vm_fault: always use a packet on the stack

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There are valid use cases where a remote page fault has no available
thread data/packet available to use, e.g. when device driver threads
need to access the data (BXI).

Do the per thread data lookup to use the right channel/tid if available,
and use mcctrl_ikc_send_wait with a new message number directly.

The fault is no longer handled in mckernel syscall forwarding code but
in the ikc handler directly in irq, this should be ok because page
faults are interrupts anyway so the code should be irq-safe.

Change-Id: Ie60f413cdaee6c1a824b4a2c93637899cb9bf9c9
This commit is contained in:
Dominique Martinet
2018-12-25 10:58:58 +01:00
committed by Dominique Martinet
parent 8074445d59
commit a5d5baf8a8
7 changed files with 150 additions and 303 deletions
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42
kernel/host.c
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@ -599,6 +599,7 @@ static int syscall_packet_handler(struct ihk_ikc_channel_desc *c,
int ret = 0;
struct perf_ctrl_desc *pcd;
unsigned int mode = 0;
unsigned long t_s = 0;
switch (packet->msg) {
case SCD_MSG_INIT_CHANNEL_ACKED:
@ -660,6 +661,47 @@ static int syscall_packet_handler(struct ihk_ikc_channel_desc *c,
ret = 0;
break;
case SCD_MSG_REMOTE_PAGE_FAULT:
thread = find_thread(0, packet->fault_tid);
if (!thread) {
kprintf("%s: WARNING: no thread for remote pf %d\n",
__func__, packet->fault_tid);
pckt.err = ret = -EINVAL;
goto out_remote_pf;
}
#ifdef PROFILE_ENABLE
/* We cannot use thread->profile_start_ts here because the
* caller may be utilizing it already */
if (thread->profile) {
t_s = rdtsc();
}
#endif // PROFILE_ENABLE
dkprintf("remote page fault,pid=%d,va=%lx,reason=%x\n",
thread->proc->pid, packet->fault_address,
packet->fault_reason|PF_POPULATE);
pckt.err = page_fault_process_vm(thread->vm,
(void *)packet->fault_address,
packet->fault_reason|PF_POPULATE);
#ifdef PROFILE_ENABLE
if (thread->profile) {
profile_event_add(PROFILE_remote_page_fault,
(rdtsc() - t_s));
}
#endif // PROFILE_ENABLE
thread_unlock(thread);
out_remote_pf:
pckt.msg = SCD_MSG_REMOTE_PAGE_FAULT_ANSWER;
pckt.ref = packet->ref;
pckt.arg = packet->arg;
pckt.reply = packet->reply;
pckt.pid = packet->pid;
syscall_channel_send(resp_channel, &pckt);
break;
case SCD_MSG_SEND_SIGNAL:
pp = ihk_mc_map_memory(NULL, packet->arg, sizeof(struct mcctrl_signal));
sp = (struct mcctrl_signal *)ihk_mc_map_virtual(pp, 1, PTATTR_WRITABLE | PTATTR_ACTIVE);