direct-io.hg

view extras/mini-os/hypervisor.c @ 7172:9c6b39746b78

Fix localhost live migration. We were overvigorously wiping out the store
entries when a domain closed and on save, which meant that the /vm entries
disappeared when a localhost migration occurred. XendCheckpoint has had extra
exception handling and logging added. It also now calls back through
XendDomain.restore_,which has the correct locking semantics to prevent race
conditions during migration.

Added assertions to XendCheckpoint to ensure that the channels are set after
XendDomainInfo.restore. I don't see why they would not be, and the old code
meant that in the case that they were not, IntroduceDomain would not be called
on the new domain, breaking Xend restart.

relocate calls through XendDomain.domain_restore_fd rather than directly to
XendCheckpoint to isolate XendCheckpoint from the rest of the world, and to
allow XendDomain to pass itself into XendCheckpoint for a callback.

Simplify the XendCheckpoint / XendDomainInfo interlock, giving only two
states, OK and TERMINATED. If XendCheckpoint asks for a suspend, but sees a
shutdown, it is valid for it to proceed -- either way the domain has stopped.
Higher level tools may wish to disallow this, but at the very least, there is
no sense in waiting for a suspend that will never come.

Signed-off-by: Ewan Mellor <ewan@xensource.com>
author emellor@ewan
date Tue Oct 04 11:14:50 2005 +0100 (2005-10-04)
parents a83ac0806d6b
children 198828cc103b
line source
1 /******************************************************************************
2 * hypervisor.c
3 *
4 * Communication to/from hypervisor.
5 *
6 * Copyright (c) 2002-2003, K A Fraser
7 * Copyright (c) 2005, Grzegorz Milos, gm281@cam.ac.uk,Intel Research Cambridge
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a copy
10 * of this software and associated documentation files (the "Software"), to
11 * deal in the Software without restriction, including without limitation the
12 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
13 * sell copies of the Software, and to permit persons to whom the Software is
14 * furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
22 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
24 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
25 * DEALINGS IN THE SOFTWARE.
26 */
28 #include <os.h>
29 #include <hypervisor.h>
30 #include <events.h>
32 #define active_evtchns(cpu,sh,idx) \
33 ((sh)->evtchn_pending[idx] & \
34 ~(sh)->evtchn_mask[idx])
36 void do_hypervisor_callback(struct pt_regs *regs)
37 {
38 u32 l1, l2;
39 unsigned int l1i, l2i, port;
40 int cpu = 0;
41 shared_info_t *s = HYPERVISOR_shared_info;
42 vcpu_info_t *vcpu_info = &s->vcpu_data[cpu];
44 vcpu_info->evtchn_upcall_pending = 0;
46 /* NB. No need for a barrier here -- XCHG is a barrier on x86. */
47 l1 = xchg(&vcpu_info->evtchn_pending_sel, 0);
48 while ( l1 != 0 )
49 {
50 l1i = __ffs(l1);
51 l1 &= ~(1 << l1i);
53 while ( (l2 = active_evtchns(cpu, s, l1i)) != 0 )
54 {
55 l2i = __ffs(l2);
56 l2 &= ~(1 << l2i);
58 port = (l1i << 5) + l2i;
59 do_event(port, regs);
60 }
61 }
62 }
65 inline void mask_evtchn(u32 port)
66 {
67 shared_info_t *s = HYPERVISOR_shared_info;
68 synch_set_bit(port, &s->evtchn_mask[0]);
69 }
71 inline void unmask_evtchn(u32 port)
72 {
73 shared_info_t *s = HYPERVISOR_shared_info;
74 vcpu_info_t *vcpu_info = &s->vcpu_data[smp_processor_id()];
76 synch_clear_bit(port, &s->evtchn_mask[0]);
78 /*
79 * The following is basically the equivalent of 'hw_resend_irq'. Just like
80 * a real IO-APIC we 'lose the interrupt edge' if the channel is masked.
81 */
82 if ( synch_test_bit (port, &s->evtchn_pending[0]) &&
83 !synch_test_and_set_bit(port>>5, &vcpu_info->evtchn_pending_sel) )
84 {
85 vcpu_info->evtchn_upcall_pending = 1;
86 if ( !vcpu_info->evtchn_upcall_mask )
87 force_evtchn_callback();
88 }
89 }
91 inline void clear_evtchn(u32 port)
92 {
93 shared_info_t *s = HYPERVISOR_shared_info;
94 synch_clear_bit(port, &s->evtchn_pending[0]);
95 }