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 */
27
28#include <mini-os/os.h>
29#include <mini-os/lib.h>
30#include <mini-os/hypervisor.h>
31#include <mini-os/events.h>
32
33#define active_evtchns(cpu,sh,idx)              \
34    ((sh)->evtchn_pending[idx] &                \
35     ~(sh)->evtchn_mask[idx])
36
37int _minios_in_hypervisor_callback;
38
39void _minios_do_hypervisor_callback(struct pt_regs *regs)
40{
41    unsigned long  l1, l2, l1i, l2i;
42    unsigned int   port;
43    int            cpu = 0;
44    shared_info_t *s = HYPERVISOR_shared_info;
45    vcpu_info_t   *vcpu_info = &s->vcpu_info[cpu];
46
47    _minios_in_hypervisor_callback = 1;
48
49    vcpu_info->evtchn_upcall_pending = 0;
50    /* NB x86. No need for a barrier here -- XCHG is a barrier on x86. */
51#if !defined(__i386__) && !defined(__x86_64__)
52    /* Clear master flag /before/ clearing selector flag. */
53    wmb();
54#endif
55    l1 = xchg(&vcpu_info->evtchn_pending_sel, 0);
56    while ( l1 != 0 )
57    {
58        l1i = __ffs(l1);
59        l1 &= ~(1UL << l1i);
60
61        while ( (l2 = active_evtchns(cpu, s, l1i)) != 0 )
62        {
63            l2i = __ffs(l2);
64            l2 &= ~(1UL << l2i);
65
66            port = (l1i * (sizeof(unsigned long) * 8)) + l2i;
67			do_event(port, regs);
68        }
69    }
70
71    _minios_in_hypervisor_callback = 0;
72}
73
74void minios_force_evtchn_callback(void)
75{
76    int save;
77    vcpu_info_t *vcpu;
78    vcpu = &HYPERVISOR_shared_info->vcpu_info[smp_processor_id()];
79    save = vcpu->evtchn_upcall_mask;
80
81    while (vcpu->evtchn_upcall_pending) {
82        vcpu->evtchn_upcall_mask = 1;
83        barrier();
84        _minios_do_hypervisor_callback(NULL);
85        barrier();
86        vcpu->evtchn_upcall_mask = save;
87        barrier();
88    };
89}
90
91inline void minios_mask_evtchn(uint32_t port)
92{
93    shared_info_t *s = HYPERVISOR_shared_info;
94    synch_set_bit(port, &s->evtchn_mask[0]);
95}
96
97inline void minios_unmask_evtchn(uint32_t port)
98{
99    shared_info_t *s = HYPERVISOR_shared_info;
100    vcpu_info_t *vcpu_info = &s->vcpu_info[smp_processor_id()];
101
102    synch_clear_bit(port, &s->evtchn_mask[0]);
103
104    /*
105     * The following is basically the equivalent of 'hw_resend_irq'. Just like
106     * a real IO-APIC we 'lose the interrupt edge' if the channel is masked.
107     */
108    if (  synch_test_bit        (port,    &s->evtchn_pending[0]) &&
109         !synch_test_and_set_bit(port / (sizeof(unsigned long) * 8),
110              &vcpu_info->evtchn_pending_sel) )
111    {
112        vcpu_info->evtchn_upcall_pending = 1;
113        if ( !vcpu_info->evtchn_upcall_mask )
114            minios_force_evtchn_callback();
115    }
116}
117
118inline void minios_clear_evtchn(uint32_t port)
119{
120    shared_info_t *s = HYPERVISOR_shared_info;
121    synch_clear_bit(port, &s->evtchn_pending[0]);
122}
123
124int minios_hypercall(unsigned op, unsigned long a0,
125		     unsigned long a1, unsigned long a2,
126		     unsigned long a3, unsigned long a4)
127{
128	multicall_entry_t call;
129	int ret;
130
131	call.op = op;
132	call.args[0] = a0;
133	call.args[1] = a1;
134	call.args[2] = a2;
135	call.args[3] = a3;
136	call.args[4] = a4;
137
138	ret = HYPERVISOR_multicall(&call, 1);
139
140	return ret;
141}
142