| 1 | /****************************************************************************** |
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| 2 | * multicall.c |
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| 3 | */ |
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| 4 | |
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| 5 | #include <xen/config.h> |
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| 6 | #include <xen/types.h> |
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| 7 | #include <xen/lib.h> |
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| 8 | #include <xen/mm.h> |
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| 9 | #include <xen/sched.h> |
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| 10 | #include <xen/event.h> |
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| 11 | #include <xen/multicall.h> |
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| 12 | #include <xen/guest_access.h> |
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| 13 | #include <xen/perfc.h> |
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| 14 | #include <asm/current.h> |
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| 15 | #include <asm/hardirq.h> |
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| 16 | |
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| 17 | #ifndef COMPAT |
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| 18 | DEFINE_PER_CPU(struct mc_state, mc_state); |
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| 19 | typedef long ret_t; |
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| 20 | #endif |
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| 21 | |
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| 22 | ret_t |
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| 23 | do_multicall( |
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| 24 | XEN_GUEST_HANDLE(multicall_entry_t) call_list, unsigned int nr_calls) |
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| 25 | { |
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| 26 | struct mc_state *mcs = &this_cpu(mc_state); |
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| 27 | unsigned int i; |
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| 28 | |
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| 29 | if ( unlikely(__test_and_set_bit(_MCSF_in_multicall, &mcs->flags)) ) |
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| 30 | { |
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| 31 | gdprintk(XENLOG_INFO, "Multicall reentry is disallowed.\n"); |
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| 32 | return -EINVAL; |
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| 33 | } |
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| 34 | |
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| 35 | if ( unlikely(!guest_handle_okay(call_list, nr_calls)) ) |
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| 36 | goto fault; |
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| 37 | |
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| 38 | for ( i = 0; i < nr_calls; i++ ) |
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| 39 | { |
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| 40 | if ( hypercall_preempt_check() ) |
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| 41 | goto preempted; |
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| 42 | |
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| 43 | if ( unlikely(__copy_from_guest(&mcs->call, call_list, 1)) ) |
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| 44 | goto fault; |
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| 45 | |
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| 46 | do_multicall_call(&mcs->call); |
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| 47 | |
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| 48 | #ifndef NDEBUG |
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| 49 | { |
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| 50 | /* |
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| 51 | * Deliberately corrupt the contents of the multicall structure. |
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| 52 | * The caller must depend only on the 'result' field on return. |
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| 53 | */ |
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| 54 | struct multicall_entry corrupt; |
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| 55 | memset(&corrupt, 0xAA, sizeof(corrupt)); |
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| 56 | (void)__copy_to_guest(call_list, &corrupt, 1); |
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| 57 | } |
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| 58 | #endif |
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| 59 | |
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| 60 | if ( unlikely(__copy_field_to_guest(call_list, &mcs->call, result)) ) |
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| 61 | goto fault; |
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| 62 | |
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| 63 | if ( test_bit(_MCSF_call_preempted, &mcs->flags) ) |
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| 64 | { |
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| 65 | /* Copy the sub-call continuation. */ |
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| 66 | (void)__copy_to_guest(call_list, &mcs->call, 1); |
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| 67 | goto preempted; |
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| 68 | } |
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| 69 | |
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| 70 | guest_handle_add_offset(call_list, 1); |
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| 71 | } |
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| 72 | |
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| 73 | perfc_incr(calls_to_multicall); |
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| 74 | perfc_add(calls_from_multicall, nr_calls); |
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| 75 | mcs->flags = 0; |
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| 76 | return 0; |
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| 77 | |
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| 78 | fault: |
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| 79 | perfc_incr(calls_to_multicall); |
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| 80 | mcs->flags = 0; |
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| 81 | return -EFAULT; |
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| 82 | |
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| 83 | preempted: |
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| 84 | perfc_add(calls_from_multicall, i); |
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| 85 | mcs->flags = 0; |
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| 86 | return hypercall_create_continuation( |
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| 87 | __HYPERVISOR_multicall, "hi", call_list, nr_calls-i); |
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| 88 | } |
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| 89 | |
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| 90 | /* |
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| 91 | * Local variables: |
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| 92 | * mode: C |
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| 93 | * c-set-style: "BSD" |
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| 94 | * c-basic-offset: 4 |
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| 95 | * tab-width: 4 |
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| 96 | * indent-tabs-mode: nil |
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| 97 | * End: |
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| 98 | */ |
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