// SPDX-License-Identifier: GPL-2.0 /* * Copyright © 2019 Oracle and/or its affiliates. All rights reserved. * Copyright © 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved. * * KVM Xen emulation */ #include "x86.h" #include "xen.h" #include "hyperv.h" #include "lapic.h" #include #include #include #include #include #include #include #include #include #include "trace.h" static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm); static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data); static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r); DEFINE_STATIC_KEY_DEFERRED_FALSE(kvm_xen_enabled, HZ); static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn) { struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache; struct pvclock_wall_clock *wc; gpa_t gpa = gfn_to_gpa(gfn); u32 *wc_sec_hi; u32 wc_version; u64 wall_nsec; int ret = 0; int idx = srcu_read_lock(&kvm->srcu); if (gfn == GPA_INVALID) { kvm_gpc_deactivate(kvm, gpc); goto out; } do { ret = kvm_gpc_activate(kvm, gpc, NULL, KVM_HOST_USES_PFN, gpa, PAGE_SIZE); if (ret) goto out; /* * This code mirrors kvm_write_wall_clock() except that it writes * directly through the pfn cache and doesn't mark the page dirty. */ wall_nsec = ktime_get_real_ns() - get_kvmclock_ns(kvm); /* It could be invalid again already, so we need to check */ read_lock_irq(&gpc->lock); if (gpc->valid) break; read_unlock_irq(&gpc->lock); } while (1); /* Paranoia checks on the 32-bit struct layout */ BUILD_BUG_ON(offsetof(struct compat_shared_info, wc) != 0x900); BUILD_BUG_ON(offsetof(struct compat_shared_info, arch.wc_sec_hi) != 0x924); BUILD_BUG_ON(offsetof(struct pvclock_vcpu_time_info, version) != 0); #ifdef CONFIG_X86_64 /* Paranoia checks on the 64-bit struct layout */ BUILD_BUG_ON(offsetof(struct shared_info, wc) != 0xc00); BUILD_BUG_ON(offsetof(struct shared_info, wc_sec_hi) != 0xc0c); if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) { struct shared_info *shinfo = gpc->khva; wc_sec_hi = &shinfo->wc_sec_hi; wc = &shinfo->wc; } else #endif { struct compat_shared_info *shinfo = gpc->khva; wc_sec_hi = &shinfo->arch.wc_sec_hi; wc = &shinfo->wc; } /* Increment and ensure an odd value */ wc_version = wc->version = (wc->version + 1) | 1; smp_wmb(); wc->nsec = do_div(wall_nsec, 1000000000); wc->sec = (u32)wall_nsec; *wc_sec_hi = wall_nsec >> 32; smp_wmb(); wc->version = wc_version + 1; read_unlock_irq(&gpc->lock); kvm_make_all_cpus_request(kvm, KVM_REQ_MASTERCLOCK_UPDATE); out: srcu_read_unlock(&kvm->srcu, idx); return ret; } void kvm_xen_inject_timer_irqs(struct kvm_vcpu *vcpu) { if (atomic_read(&vcpu->arch.xen.timer_pending) > 0) { struct kvm_xen_evtchn e; e.vcpu_id = vcpu->vcpu_id; e.vcpu_idx = vcpu->vcpu_idx; e.port = vcpu->arch.xen.timer_virq; e.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL; kvm_xen_set_evtchn(&e, vcpu->kvm); vcpu->arch.xen.timer_expires = 0; atomic_set(&vcpu->arch.xen.timer_pending, 0); } } static enum hrtimer_restart xen_timer_callback(struct hrtimer *timer) { struct kvm_vcpu *vcpu = container_of(timer, struct kvm_vcpu, arch.xen.timer); if (atomic_read(&vcpu->arch.xen.timer_pending)) return HRTIMER_NORESTART; atomic_inc(&vcpu->arch.xen.timer_pending); kvm_make_request(KVM_REQ_UNBLOCK, vcpu); kvm_vcpu_kick(vcpu); return HRTIMER_NORESTART; } static void kvm_xen_start_timer(struct kvm_vcpu *vcpu, u64 guest_abs, s64 delta_ns) { atomic_set(&vcpu->arch.xen.timer_pending, 0); vcpu->arch.xen.timer_expires = guest_abs; if (delta_ns <= 0) { xen_timer_callback(&vcpu->arch.xen.timer); } else { ktime_t ktime_now = ktime_get(); hrtimer_start(&vcpu->arch.xen.timer, ktime_add_ns(ktime_now, delta_ns), HRTIMER_MODE_ABS_HARD); } } static void kvm_xen_stop_timer(struct kvm_vcpu *vcpu) { hrtimer_cancel(&vcpu->arch.xen.timer); vcpu->arch.xen.timer_expires = 0; atomic_set(&vcpu->arch.xen.timer_pending, 0); } static void kvm_xen_init_timer(struct kvm_vcpu *vcpu) { hrtimer_init(&vcpu->arch.xen.timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD); vcpu->arch.xen.timer.function = xen_timer_callback; } static void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, bool atomic) { struct kvm_vcpu_xen *vx = &v->arch.xen; struct gfn_to_pfn_cache *gpc1 = &vx->runstate_cache; struct gfn_to_pfn_cache *gpc2 = &vx->runstate2_cache; size_t user_len, user_len1, user_len2; struct vcpu_runstate_info rs; unsigned long flags; size_t times_ofs; uint8_t *update_bit; uint64_t *rs_times; int *rs_state; /* * The only difference between 32-bit and 64-bit versions of the * runstate struct is the alignment of uint64_t in 32-bit, which * means that the 64-bit version has an additional 4 bytes of * padding after the first field 'state'. Let's be really really * paranoid about that, and matching it with our internal data * structures that we memcpy into it... */ BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) != 0); BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state) != 0); BUILD_BUG_ON(sizeof(struct compat_vcpu_runstate_info) != 0x2c); #ifdef CONFIG_X86_64 /* * The 64-bit structure has 4 bytes of padding before 'state_entry_time' * so each subsequent field is shifted by 4, and it's 4 bytes longer. */ BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) != offsetof(struct compat_vcpu_runstate_info, state_entry_time) + 4); BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, time) != offsetof(struct compat_vcpu_runstate_info, time) + 4); BUILD_BUG_ON(sizeof(struct vcpu_runstate_info) != 0x2c + 4); #endif /* * The state field is in the same place at the start of both structs, * and is the same size (int) as vx->current_runstate. */ BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) != offsetof(struct compat_vcpu_runstate_info, state)); BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state) != sizeof(vx->current_runstate)); BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state) != sizeof(vx->current_runstate)); /* * The state_entry_time field is 64 bits in both versions, and the * XEN_RUNSTATE_UPDATE flag is in the top bit, which given that x86 * is little-endian means that it's in the last *byte* of the word. * That detail is important later. */ BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state_entry_time) != sizeof(uint64_t)); BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state_entry_time) != sizeof(uint64_t)); BUILD_BUG_ON((XEN_RUNSTATE_UPDATE >> 56) != 0x80); /* * The time array is four 64-bit quantities in both versions, matching * the vx->runstate_times and immediately following state_entry_time. */ BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) != offsetof(struct vcpu_runstate_info, time) - sizeof(uint64_t)); BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state_entry_time) != offsetof(struct compat_vcpu_runstate_info, time) - sizeof(uint64_t)); BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) != sizeof_field(struct compat_vcpu_runstate_info, time)); BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) != sizeof(vx->runstate_times)); if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) { user_len = sizeof(struct vcpu_runstate_info); times_ofs = offsetof(struct vcpu_runstate_info, state_entry_time); } else { user_len = sizeof(struct compat_vcpu_runstate_info); times_ofs = offsetof(struct compat_vcpu_runstate_info, state_entry_time); } /* * There are basically no alignment constraints. The guest can set it * up so it crosses from one page to the next, and at arbitrary byte * alignment (and the 32-bit ABI doesn't align the 64-bit integers * anyway, even if the overall struct had been 64-bit aligned). */ if ((gpc1->gpa & ~PAGE_MASK) + user_len >= PAGE_SIZE) { user_len1 = PAGE_SIZE - (gpc1->gpa & ~PAGE_MASK); user_len2 = user_len - user_len1; } else { user_len1 = user_len; user_len2 = 0; } BUG_ON(user_len1 + user_len2 != user_len); retry: /* * Attempt to obtain the GPC lock on *both* (if there are two) * gfn_to_pfn caches that cover the region. */ read_lock_irqsave(&gpc1->lock, flags); while (!kvm_gfn_to_pfn_cache_check(v->kvm, gpc1, gpc1->gpa, user_len1)) { read_unlock_irqrestore(&gpc1->lock, flags); /* When invoked from kvm_sched_out() we cannot sleep */ if (atomic) return; if (kvm_gfn_to_pfn_cache_refresh(v->kvm, gpc1, gpc1->gpa, user_len1)) return; read_lock_irqsave(&gpc1->lock, flags); } if (likely(!user_len2)) { /* * Set up three pointers directly to the runstate_info * struct in the guest (via the GPC). * * • @rs_state → state field * • @rs_times → state_entry_time field. * • @update_bit → last byte of state_entry_time, which * contains the XEN_RUNSTATE_UPDATE bit. */ rs_state = gpc1->khva; rs_times = gpc1->khva + times_ofs; update_bit = ((void *)(&rs_times[1])) - 1; } else { /* * The guest's runstate_info is split across two pages and we * need to hold and validate both GPCs simultaneously. We can * declare a lock ordering GPC1 > GPC2 because nothing else * takes them more than one at a time. */ read_lock(&gpc2->lock); if (!kvm_gfn_to_pfn_cache_check(v->kvm, gpc2, gpc2->gpa, user_len2)) { read_unlock(&gpc2->lock); read_unlock_irqrestore(&gpc1->lock, flags); /* When invoked from kvm_sched_out() we cannot sleep */ if (atomic) return; /* * Use kvm_gpc_activate() here because if the runstate * area was configured in 32-bit mode and only extends * to the second page now because the guest changed to * 64-bit mode, the second GPC won't have been set up. */ if (kvm_gpc_activate(v->kvm, gpc2, NULL, KVM_HOST_USES_PFN, gpc1->gpa + user_len1, user_len2)) return; /* * We dropped the lock on GPC1 so we have to go all the * way back and revalidate that too. */ goto retry; } /* * In this case, the runstate_info struct will be assembled on * the kernel stack (compat or not as appropriate) and will * be copied to GPC1/GPC2 with a dual memcpy. Set up the three * rs pointers accordingly. */ rs_times = &rs.state_entry_time; /* * The rs_state pointer points to the start of what we'll * copy to the guest, which in the case of a compat guest * is the 32-bit field that the compiler thinks is padding. */ rs_state = ((void *)rs_times) - times_ofs; /* * The update_bit is still directly in the guest memory, * via one GPC or the other. */ if (user_len1 >= times_ofs + sizeof(uint64_t)) update_bit = gpc1->khva + times_ofs + sizeof(uint64_t) - 1; else update_bit = gpc2->khva + times_ofs + sizeof(uint64_t) - 1 - user_len1; #ifdef CONFIG_X86_64 /* * Don't leak kernel memory through the padding in the 64-bit * version of the struct. */ memset(&rs, 0, offsetof(struct vcpu_runstate_info, state_entry_time)); #endif } /* * First, set the XEN_RUNSTATE_UPDATE bit in the top bit of the * state_entry_time field, directly in the guest. We need to set * that (and write-barrier) before writing to the rest of the * structure, and clear it last. Just as Xen does, we address the * single *byte* in which it resides because it might be in a * different cache line to the rest of the 64-bit word, due to * the (lack of) alignment constraints. */ *update_bit = (vx->runstate_entry_time | XEN_RUNSTATE_UPDATE) >> 56; smp_wmb(); /* * Now assemble the actual structure, either on our kernel stack * or directly in the guest according to how the rs_state and * rs_times pointers were set up above. */ *rs_state = vx->current_runstate; rs_times[0] = vx->runstate_entry_time | XEN_RUNSTATE_UPDATE; memcpy(rs_times + 1, vx->runstate_times, sizeof(vx->runstate_times)); /* For the split case, we have to then copy it to the guest. */ if (user_len2) { memcpy(gpc1->khva, rs_state, user_len1); memcpy(gpc2->khva, ((void *)rs_state) + user_len1, user_len2); } smp_wmb(); /* Finally, clear the XEN_RUNSTATE_UPDATE bit. */ *update_bit = vx->runstate_entry_time >> 56; smp_wmb(); if (user_len2) read_unlock(&gpc2->lock); read_unlock_irqrestore(&gpc1->lock, flags); mark_page_dirty_in_slot(v->kvm, gpc1->memslot, gpc1->gpa >> PAGE_SHIFT); if (user_len2) mark_page_dirty_in_slot(v->kvm, gpc2->memslot, gpc2->gpa >> PAGE_SHIFT); } void kvm_xen_update_runstate(struct kvm_vcpu *v, int state) { struct kvm_vcpu_xen *vx = &v->arch.xen; u64 now = get_kvmclock_ns(v->kvm); u64 delta_ns = now - vx->runstate_entry_time; u64 run_delay = current->sched_info.run_delay; if (unlikely(!vx->runstate_entry_time)) vx->current_runstate = RUNSTATE_offline; /* * Time waiting for the scheduler isn't "stolen" if the * vCPU wasn't running anyway. */ if (vx->current_runstate == RUNSTATE_running) { u64 steal_ns = run_delay - vx->last_steal; delta_ns -= steal_ns; vx->runstate_times[RUNSTATE_runnable] += steal_ns; } vx->last_steal = run_delay; vx->runstate_times[vx->current_runstate] += delta_ns; vx->current_runstate = state; vx->runstate_entry_time = now; if (vx->runstate_cache.active) kvm_xen_update_runstate_guest(v, state == RUNSTATE_runnable); } static void kvm_xen_inject_vcpu_vector(struct kvm_vcpu *v) { struct kvm_lapic_irq irq = { }; int r; irq.dest_id = v->vcpu_id; irq.vector = v->arch.xen.upcall_vector; irq.dest_mode = APIC_DEST_PHYSICAL; irq.shorthand = APIC_DEST_NOSHORT; irq.delivery_mode = APIC_DM_FIXED; irq.level = 1; /* The fast version will always work for physical unicast */ WARN_ON_ONCE(!kvm_irq_delivery_to_apic_fast(v->kvm, NULL, &irq, &r, NULL)); } /* * On event channel delivery, the vcpu_info may not have been accessible. * In that case, there are bits in vcpu->arch.xen.evtchn_pending_sel which * need to be marked into the vcpu_info (and evtchn_upcall_pending set). * Do so now that we can sleep in the context of the vCPU to bring the * page in, and refresh the pfn cache for it. */ void kvm_xen_inject_pending_events(struct kvm_vcpu *v) { unsigned long evtchn_pending_sel = READ_ONCE(v->arch.xen.evtchn_pending_sel); struct gfn_to_pfn_cache *gpc = &v->arch.xen.vcpu_info_cache; unsigned long flags; if (!evtchn_pending_sel) return; /* * Yes, this is an open-coded loop. But that's just what put_user() * does anyway. Page it in and retry the instruction. We're just a * little more honest about it. */ read_lock_irqsave(&gpc->lock, flags); while (!kvm_gfn_to_pfn_cache_check(v->kvm, gpc, gpc->gpa, sizeof(struct vcpu_info))) { read_unlock_irqrestore(&gpc->lock, flags); if (kvm_gfn_to_pfn_cache_refresh(v->kvm, gpc, gpc->gpa, sizeof(struct vcpu_info))) return; read_lock_irqsave(&gpc->lock, flags); } /* Now gpc->khva is a valid kernel address for the vcpu_info */ if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) { struct vcpu_info *vi = gpc->khva; asm volatile(LOCK_PREFIX "orq %0, %1\n" "notq %0\n" LOCK_PREFIX "andq %0, %2\n" : "=r" (evtchn_pending_sel), "+m" (vi->evtchn_pending_sel), "+m" (v->arch.xen.evtchn_pending_sel) : "0" (evtchn_pending_sel)); WRITE_ONCE(vi->evtchn_upcall_pending, 1); } else { u32 evtchn_pending_sel32 = evtchn_pending_sel; struct compat_vcpu_info *vi = gpc->khva; asm volatile(LOCK_PREFIX "orl %0, %1\n" "notl %0\n" LOCK_PREFIX "andl %0, %2\n" : "=r" (evtchn_pending_sel32), "+m" (vi->evtchn_pending_sel), "+m" (v->arch.xen.evtchn_pending_sel) : "0" (evtchn_pending_sel32)); WRITE_ONCE(vi->evtchn_upcall_pending, 1); } read_unlock_irqrestore(&gpc->lock, flags); /* For the per-vCPU lapic vector, deliver it as MSI. */ if (v->arch.xen.upcall_vector) kvm_xen_inject_vcpu_vector(v); mark_page_dirty_in_slot(v->kvm, gpc->memslot, gpc->gpa >> PAGE_SHIFT); } int __kvm_xen_has_interrupt(struct kvm_vcpu *v) { struct gfn_to_pfn_cache *gpc = &v->arch.xen.vcpu_info_cache; unsigned long flags; u8 rc = 0; /* * If the global upcall vector (HVMIRQ_callback_vector) is set and * the vCPU's evtchn_upcall_pending flag is set, the IRQ is pending. */ /* No need for compat handling here */ BUILD_BUG_ON(offsetof(struct vcpu_info, evtchn_upcall_pending) != offsetof(struct compat_vcpu_info, evtchn_upcall_pending)); BUILD_BUG_ON(sizeof(rc) != sizeof_field(struct vcpu_info, evtchn_upcall_pending)); BUILD_BUG_ON(sizeof(rc) != sizeof_field(struct compat_vcpu_info, evtchn_upcall_pending)); read_lock_irqsave(&gpc->lock, flags); while (!kvm_gfn_to_pfn_cache_check(v->kvm, gpc, gpc->gpa, sizeof(struct vcpu_info))) { read_unlock_irqrestore(&gpc->lock, flags); /* * This function gets called from kvm_vcpu_block() after setting the * task to TASK_INTERRUPTIBLE, to see if it needs to wake immediately * from a HLT. So we really mustn't sleep. If the page ended up absent * at that point, just return 1 in order to trigger an immediate wake, * and we'll end up getting called again from a context where we *can* * fault in the page and wait for it. */ if (in_atomic() || !task_is_running(current)) return 1; if (kvm_gfn_to_pfn_cache_refresh(v->kvm, gpc, gpc->gpa, sizeof(struct vcpu_info))) { /* * If this failed, userspace has screwed up the * vcpu_info mapping. No interrupts for you. */ return 0; } read_lock_irqsave(&gpc->lock, flags); } rc = ((struct vcpu_info *)gpc->khva)->evtchn_upcall_pending; read_unlock_irqrestore(&gpc->lock, flags); return rc; } int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) { int r = -ENOENT; switch (data->type) { case KVM_XEN_ATTR_TYPE_LONG_MODE: if (!IS_ENABLED(CONFIG_64BIT) && data->u.long_mode) { r = -EINVAL; } else { mutex_lock(&kvm->lock); kvm->arch.xen.long_mode = !!data->u.long_mode; mutex_unlock(&kvm->lock); r = 0; } break; case KVM_XEN_ATTR_TYPE_SHARED_INFO: mutex_lock(&kvm->lock); r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn); mutex_unlock(&kvm->lock); break; case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR: if (data->u.vector && data->u.vector < 0x10) r = -EINVAL; else { mutex_lock(&kvm->lock); kvm->arch.xen.upcall_vector = data->u.vector; mutex_unlock(&kvm->lock); r = 0; } break; case KVM_XEN_ATTR_TYPE_EVTCHN: r = kvm_xen_setattr_evtchn(kvm, data); break; case KVM_XEN_ATTR_TYPE_XEN_VERSION: mutex_lock(&kvm->lock); kvm->arch.xen.xen_version = data->u.xen_version; mutex_unlock(&kvm->lock); r = 0; break; default: break; } return r; } int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) { int r = -ENOENT; mutex_lock(&kvm->lock); switch (data->type) { case KVM_XEN_ATTR_TYPE_LONG_MODE: data->u.long_mode = kvm->arch.xen.long_mode; r = 0; break; case KVM_XEN_ATTR_TYPE_SHARED_INFO: if (kvm->arch.xen.shinfo_cache.active) data->u.shared_info.gfn = gpa_to_gfn(kvm->arch.xen.shinfo_cache.gpa); else data->u.shared_info.gfn = GPA_INVALID; r = 0; break; case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR: data->u.vector = kvm->arch.xen.upcall_vector; r = 0; break; case KVM_XEN_ATTR_TYPE_XEN_VERSION: data->u.xen_version = kvm->arch.xen.xen_version; r = 0; break; default: break; } mutex_unlock(&kvm->lock); return r; } int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) { int idx, r = -ENOENT; mutex_lock(&vcpu->kvm->lock); idx = srcu_read_lock(&vcpu->kvm->srcu); switch (data->type) { case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO: /* No compat necessary here. */ BUILD_BUG_ON(sizeof(struct vcpu_info) != sizeof(struct compat_vcpu_info)); BUILD_BUG_ON(offsetof(struct vcpu_info, time) != offsetof(struct compat_vcpu_info, time)); if (data->u.gpa == GPA_INVALID) { kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.vcpu_info_cache); r = 0; break; } r = kvm_gpc_activate(vcpu->kvm, &vcpu->arch.xen.vcpu_info_cache, NULL, KVM_HOST_USES_PFN, data->u.gpa, sizeof(struct vcpu_info)); if (!r) kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); break; case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO: if (data->u.gpa == GPA_INVALID) { kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.vcpu_time_info_cache); r = 0; break; } r = kvm_gpc_activate(vcpu->kvm, &vcpu->arch.xen.vcpu_time_info_cache, NULL, KVM_HOST_USES_PFN, data->u.gpa, sizeof(struct pvclock_vcpu_time_info)); if (!r) kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); break; case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR: { size_t sz, sz1, sz2; if (!sched_info_on()) { r = -EOPNOTSUPP; break; } if (data->u.gpa == GPA_INVALID) { r = 0; deactivate_out: kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.runstate_cache); kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.runstate2_cache); break; } /* * If the guest switches to 64-bit mode after setting the runstate * address, that's actually OK. kvm_xen_update_runstate_guest() * will cope. */ if (IS_ENABLED(CONFIG_64BIT) && vcpu->kvm->arch.xen.long_mode) sz = sizeof(struct vcpu_runstate_info); else sz = sizeof(struct compat_vcpu_runstate_info); /* How much fits in the (first) page? */ sz1 = PAGE_SIZE - (data->u.gpa & ~PAGE_MASK); r = kvm_gpc_activate(vcpu->kvm, &vcpu->arch.xen.runstate_cache, NULL, KVM_HOST_USES_PFN, data->u.gpa, sz1); if (r) goto deactivate_out; /* Either map the second page, or deactivate the second GPC */ if (sz1 >= sz) { kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.runstate2_cache); } else { sz2 = sz - sz1; BUG_ON((data->u.gpa + sz1) & ~PAGE_MASK); r = kvm_gpc_activate(vcpu->kvm, &vcpu->arch.xen.runstate2_cache, NULL, KVM_HOST_USES_PFN, data->u.gpa + sz1, sz2); if (r) goto deactivate_out; } kvm_xen_update_runstate_guest(vcpu, false); break; } case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT: if (!sched_info_on()) { r = -EOPNOTSUPP; break; } if (data->u.runstate.state > RUNSTATE_offline) { r = -EINVAL; break; } kvm_xen_update_runstate(vcpu, data->u.runstate.state); r = 0; break; case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA: if (!sched_info_on()) { r = -EOPNOTSUPP; break; } if (data->u.runstate.state > RUNSTATE_offline) { r = -EINVAL; break; } if (data->u.runstate.state_entry_time != (data->u.runstate.time_running + data->u.runstate.time_runnable + data->u.runstate.time_blocked + data->u.runstate.time_offline)) { r = -EINVAL; break; } if (get_kvmclock_ns(vcpu->kvm) < data->u.runstate.state_entry_time) { r = -EINVAL; break; } vcpu->arch.xen.current_runstate = data->u.runstate.state; vcpu->arch.xen.runstate_entry_time = data->u.runstate.state_entry_time; vcpu->arch.xen.runstate_times[RUNSTATE_running] = data->u.runstate.time_running; vcpu->arch.xen.runstate_times[RUNSTATE_runnable] = data->u.runstate.time_runnable; vcpu->arch.xen.runstate_times[RUNSTATE_blocked] = data->u.runstate.time_blocked; vcpu->arch.xen.runstate_times[RUNSTATE_offline] = data->u.runstate.time_offline; vcpu->arch.xen.last_steal = current->sched_info.run_delay; r = 0; break; case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST: if (!sched_info_on()) { r = -EOPNOTSUPP; break; } if (data->u.runstate.state > RUNSTATE_offline && data->u.runstate.state != (u64)-1) { r = -EINVAL; break; } /* The adjustment must add up */ if (data->u.runstate.state_entry_time != (data->u.runstate.time_running + data->u.runstate.time_runnable + data->u.runstate.time_blocked + data->u.runstate.time_offline)) { r = -EINVAL; break; } if (get_kvmclock_ns(vcpu->kvm) < (vcpu->arch.xen.runstate_entry_time + data->u.runstate.state_entry_time)) { r = -EINVAL; break; } vcpu->arch.xen.runstate_entry_time += data->u.runstate.state_entry_time; vcpu->arch.xen.runstate_times[RUNSTATE_running] += data->u.runstate.time_running; vcpu->arch.xen.runstate_times[RUNSTATE_runnable] += data->u.runstate.time_runnable; vcpu->arch.xen.runstate_times[RUNSTATE_blocked] += data->u.runstate.time_blocked; vcpu->arch.xen.runstate_times[RUNSTATE_offline] += data->u.runstate.time_offline; if (data->u.runstate.state <= RUNSTATE_offline) kvm_xen_update_runstate(vcpu, data->u.runstate.state); r = 0; break; case KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID: if (data->u.vcpu_id >= KVM_MAX_VCPUS) r = -EINVAL; else { vcpu->arch.xen.vcpu_id = data->u.vcpu_id; r = 0; } break; case KVM_XEN_VCPU_ATTR_TYPE_TIMER: if (data->u.timer.port && data->u.timer.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL) { r = -EINVAL; break; } if (!vcpu->arch.xen.timer.function) kvm_xen_init_timer(vcpu); /* Stop the timer (if it's running) before changing the vector */ kvm_xen_stop_timer(vcpu); vcpu->arch.xen.timer_virq = data->u.timer.port; /* Start the timer if the new value has a valid vector+expiry. */ if (data->u.timer.port && data->u.timer.expires_ns) kvm_xen_start_timer(vcpu, data->u.timer.expires_ns, data->u.timer.expires_ns - get_kvmclock_ns(vcpu->kvm)); r = 0; break; case KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR: if (data->u.vector && data->u.vector < 0x10) r = -EINVAL; else { vcpu->arch.xen.upcall_vector = data->u.vector; r = 0; } break; default: break; } srcu_read_unlock(&vcpu->kvm->srcu, idx); mutex_unlock(&vcpu->kvm->lock); return r; } int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) { int r = -ENOENT; mutex_lock(&vcpu->kvm->lock); switch (data->type) { case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO: if (vcpu->arch.xen.vcpu_info_cache.active) data->u.gpa = vcpu->arch.xen.vcpu_info_cache.gpa; else data->u.gpa = GPA_INVALID; r = 0; break; case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO: if (vcpu->arch.xen.vcpu_time_info_cache.active) data->u.gpa = vcpu->arch.xen.vcpu_time_info_cache.gpa; else data->u.gpa = GPA_INVALID; r = 0; break; case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR: if (!sched_info_on()) { r = -EOPNOTSUPP; break; } if (vcpu->arch.xen.runstate_cache.active) { data->u.gpa = vcpu->arch.xen.runstate_cache.gpa; r = 0; } break; case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT: if (!sched_info_on()) { r = -EOPNOTSUPP; break; } data->u.runstate.state = vcpu->arch.xen.current_runstate; r = 0; break; case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA: if (!sched_info_on()) { r = -EOPNOTSUPP; break; } data->u.runstate.state = vcpu->arch.xen.current_runstate; data->u.runstate.state_entry_time = vcpu->arch.xen.runstate_entry_time; data->u.runstate.time_running = vcpu->arch.xen.runstate_times[RUNSTATE_running]; data->u.runstate.time_runnable = vcpu->arch.xen.runstate_times[RUNSTATE_runnable]; data->u.runstate.time_blocked = vcpu->arch.xen.runstate_times[RUNSTATE_blocked]; data->u.runstate.time_offline = vcpu->arch.xen.runstate_times[RUNSTATE_offline]; r = 0; break; case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST: r = -EINVAL; break; case KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID: data->u.vcpu_id = vcpu->arch.xen.vcpu_id; r = 0; break; case KVM_XEN_VCPU_ATTR_TYPE_TIMER: data->u.timer.port = vcpu->arch.xen.timer_virq; data->u.timer.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL; data->u.timer.expires_ns = vcpu->arch.xen.timer_expires; r = 0; break; case KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR: data->u.vector = vcpu->arch.xen.upcall_vector; r = 0; break; default: break; } mutex_unlock(&vcpu->kvm->lock); return r; } int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data) { struct kvm *kvm = vcpu->kvm; u32 page_num = data & ~PAGE_MASK; u64 page_addr = data & PAGE_MASK; bool lm = is_long_mode(vcpu); /* Latch long_mode for shared_info pages etc. */ vcpu->kvm->arch.xen.long_mode = lm; /* * If Xen hypercall intercept is enabled, fill the hypercall * page with VMCALL/VMMCALL instructions since that's what * we catch. Else the VMM has provided the hypercall pages * with instructions of its own choosing, so use those. */ if (kvm_xen_hypercall_enabled(kvm)) { u8 instructions[32]; int i; if (page_num) return 1; /* mov imm32, %eax */ instructions[0] = 0xb8; /* vmcall / vmmcall */ static_call(kvm_x86_patch_hypercall)(vcpu, instructions + 5); /* ret */ instructions[8] = 0xc3; /* int3 to pad */ memset(instructions + 9, 0xcc, sizeof(instructions) - 9); for (i = 0; i < PAGE_SIZE / sizeof(instructions); i++) { *(u32 *)&instructions[1] = i; if (kvm_vcpu_write_guest(vcpu, page_addr + (i * sizeof(instructions)), instructions, sizeof(instructions))) return 1; } } else { /* * Note, truncation is a non-issue as 'lm' is guaranteed to be * false for a 32-bit kernel, i.e. when hva_t is only 4 bytes. */ hva_t blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64 : kvm->arch.xen_hvm_config.blob_addr_32; u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64 : kvm->arch.xen_hvm_config.blob_size_32; u8 *page; if (page_num >= blob_size) return 1; blob_addr += page_num * PAGE_SIZE; page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE); if (IS_ERR(page)) return PTR_ERR(page); if (kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE)) { kfree(page); return 1; } } return 0; } int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc) { /* Only some feature flags need to be *enabled* by userspace */ u32 permitted_flags = KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL | KVM_XEN_HVM_CONFIG_EVTCHN_SEND; if (xhc->flags & ~permitted_flags) return -EINVAL; /* * With hypercall interception the kernel generates its own * hypercall page so it must not be provided. */ if ((xhc->flags & KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL) && (xhc->blob_addr_32 || xhc->blob_addr_64 || xhc->blob_size_32 || xhc->blob_size_64)) return -EINVAL; mutex_lock(&kvm->lock); if (xhc->msr && !kvm->arch.xen_hvm_config.msr) static_branch_inc(&kvm_xen_enabled.key); else if (!xhc->msr && kvm->arch.xen_hvm_config.msr) static_branch_slow_dec_deferred(&kvm_xen_enabled); memcpy(&kvm->arch.xen_hvm_config, xhc, sizeof(*xhc)); mutex_unlock(&kvm->lock); return 0; } static int kvm_xen_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result) { kvm_rax_write(vcpu, result); return kvm_skip_emulated_instruction(vcpu); } static int kvm_xen_hypercall_complete_userspace(struct kvm_vcpu *vcpu) { struct kvm_run *run = vcpu->run; if (unlikely(!kvm_is_linear_rip(vcpu, vcpu->arch.xen.hypercall_rip))) return 1; return kvm_xen_hypercall_set_result(vcpu, run->xen.u.hcall.result); } static inline int max_evtchn_port(struct kvm *kvm) { if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) return EVTCHN_2L_NR_CHANNELS; else return COMPAT_EVTCHN_2L_NR_CHANNELS; } static bool wait_pending_event(struct kvm_vcpu *vcpu, int nr_ports, evtchn_port_t *ports) { struct kvm *kvm = vcpu->kvm; struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache; unsigned long *pending_bits; unsigned long flags; bool ret = true; int idx, i; read_lock_irqsave(&gpc->lock, flags); idx = srcu_read_lock(&kvm->srcu); if (!kvm_gfn_to_pfn_cache_check(kvm, gpc, gpc->gpa, PAGE_SIZE)) goto out_rcu; ret = false; if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) { struct shared_info *shinfo = gpc->khva; pending_bits = (unsigned long *)&shinfo->evtchn_pending; } else { struct compat_shared_info *shinfo = gpc->khva; pending_bits = (unsigned long *)&shinfo->evtchn_pending; } for (i = 0; i < nr_ports; i++) { if (test_bit(ports[i], pending_bits)) { ret = true; break; } } out_rcu: srcu_read_unlock(&kvm->srcu, idx); read_unlock_irqrestore(&gpc->lock, flags); return ret; } static bool kvm_xen_schedop_poll(struct kvm_vcpu *vcpu, bool longmode, u64 param, u64 *r) { int idx, i; struct sched_poll sched_poll; evtchn_port_t port, *ports; gpa_t gpa; if (!longmode || !lapic_in_kernel(vcpu) || !(vcpu->kvm->arch.xen_hvm_config.flags & KVM_XEN_HVM_CONFIG_EVTCHN_SEND)) return false; idx = srcu_read_lock(&vcpu->kvm->srcu); gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL); srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!gpa || kvm_vcpu_read_guest(vcpu, gpa, &sched_poll, sizeof(sched_poll))) { *r = -EFAULT; return true; } if (unlikely(sched_poll.nr_ports > 1)) { /* Xen (unofficially) limits number of pollers to 128 */ if (sched_poll.nr_ports > 128) { *r = -EINVAL; return true; } ports = kmalloc_array(sched_poll.nr_ports, sizeof(*ports), GFP_KERNEL); if (!ports) { *r = -ENOMEM; return true; } } else ports = &port; for (i = 0; i < sched_poll.nr_ports; i++) { idx = srcu_read_lock(&vcpu->kvm->srcu); gpa = kvm_mmu_gva_to_gpa_system(vcpu, (gva_t)(sched_poll.ports + i), NULL); srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!gpa || kvm_vcpu_read_guest(vcpu, gpa, &ports[i], sizeof(port))) { *r = -EFAULT; goto out; } if (ports[i] >= max_evtchn_port(vcpu->kvm)) { *r = -EINVAL; goto out; } } if (sched_poll.nr_ports == 1) vcpu->arch.xen.poll_evtchn = port; else vcpu->arch.xen.poll_evtchn = -1; set_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask); if (!wait_pending_event(vcpu, sched_poll.nr_ports, ports)) { vcpu->arch.mp_state = KVM_MP_STATE_HALTED; if (sched_poll.timeout) mod_timer(&vcpu->arch.xen.poll_timer, jiffies + nsecs_to_jiffies(sched_poll.timeout)); kvm_vcpu_halt(vcpu); if (sched_poll.timeout) del_timer(&vcpu->arch.xen.poll_timer); vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; } vcpu->arch.xen.poll_evtchn = 0; *r = 0; out: /* Really, this is only needed in case of timeout */ clear_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask); if (unlikely(sched_poll.nr_ports > 1)) kfree(ports); return true; } static void cancel_evtchn_poll(struct timer_list *t) { struct kvm_vcpu *vcpu = from_timer(vcpu, t, arch.xen.poll_timer); kvm_make_request(KVM_REQ_UNBLOCK, vcpu); kvm_vcpu_kick(vcpu); } static bool kvm_xen_hcall_sched_op(struct kvm_vcpu *vcpu, bool longmode, int cmd, u64 param, u64 *r) { switch (cmd) { case SCHEDOP_poll: if (kvm_xen_schedop_poll(vcpu, longmode, param, r)) return true; fallthrough; case SCHEDOP_yield: kvm_vcpu_on_spin(vcpu, true); *r = 0; return true; default: break; } return false; } struct compat_vcpu_set_singleshot_timer { uint64_t timeout_abs_ns; uint32_t flags; } __attribute__((packed)); static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd, int vcpu_id, u64 param, u64 *r) { struct vcpu_set_singleshot_timer oneshot; s64 delta; gpa_t gpa; int idx; if (!kvm_xen_timer_enabled(vcpu)) return false; switch (cmd) { case VCPUOP_set_singleshot_timer: if (vcpu->arch.xen.vcpu_id != vcpu_id) { *r = -EINVAL; return true; } idx = srcu_read_lock(&vcpu->kvm->srcu); gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL); srcu_read_unlock(&vcpu->kvm->srcu, idx); /* * The only difference for 32-bit compat is the 4 bytes of * padding after the interesting part of the structure. So * for a faithful emulation of Xen we have to *try* to copy * the padding and return -EFAULT if we can't. Otherwise we * might as well just have copied the 12-byte 32-bit struct. */ BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) != offsetof(struct vcpu_set_singleshot_timer, timeout_abs_ns)); BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) != sizeof_field(struct vcpu_set_singleshot_timer, timeout_abs_ns)); BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, flags) != offsetof(struct vcpu_set_singleshot_timer, flags)); BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, flags) != sizeof_field(struct vcpu_set_singleshot_timer, flags)); if (!gpa || kvm_vcpu_read_guest(vcpu, gpa, &oneshot, longmode ? sizeof(oneshot) : sizeof(struct compat_vcpu_set_singleshot_timer))) { *r = -EFAULT; return true; } delta = oneshot.timeout_abs_ns - get_kvmclock_ns(vcpu->kvm); if ((oneshot.flags & VCPU_SSHOTTMR_future) && delta < 0) { *r = -ETIME; return true; } kvm_xen_start_timer(vcpu, oneshot.timeout_abs_ns, delta); *r = 0; return true; case VCPUOP_stop_singleshot_timer: if (vcpu->arch.xen.vcpu_id != vcpu_id) { *r = -EINVAL; return true; } kvm_xen_stop_timer(vcpu); *r = 0; return true; } return false; } static bool kvm_xen_hcall_set_timer_op(struct kvm_vcpu *vcpu, uint64_t timeout, u64 *r) { if (!kvm_xen_timer_enabled(vcpu)) return false; if (timeout) { uint64_t guest_now = get_kvmclock_ns(vcpu->kvm); int64_t delta = timeout - guest_now; /* Xen has a 'Linux workaround' in do_set_timer_op() which * checks for negative absolute timeout values (caused by * integer overflow), and for values about 13 days in the * future (2^50ns) which would be caused by jiffies * overflow. For those cases, it sets the timeout 100ms in * the future (not *too* soon, since if a guest really did * set a long timeout on purpose we don't want to keep * churning CPU time by waking it up). */ if (unlikely((int64_t)timeout < 0 || (delta > 0 && (uint32_t) (delta >> 50) != 0))) { delta = 100 * NSEC_PER_MSEC; timeout = guest_now + delta; } kvm_xen_start_timer(vcpu, timeout, delta); } else { kvm_xen_stop_timer(vcpu); } *r = 0; return true; } int kvm_xen_hypercall(struct kvm_vcpu *vcpu) { bool longmode; u64 input, params[6], r = -ENOSYS; bool handled = false; u8 cpl; input = (u64)kvm_register_read(vcpu, VCPU_REGS_RAX); /* Hyper-V hypercalls get bit 31 set in EAX */ if ((input & 0x80000000) && kvm_hv_hypercall_enabled(vcpu)) return kvm_hv_hypercall(vcpu); longmode = is_64_bit_hypercall(vcpu); if (!longmode) { params[0] = (u32)kvm_rbx_read(vcpu); params[1] = (u32)kvm_rcx_read(vcpu); params[2] = (u32)kvm_rdx_read(vcpu); params[3] = (u32)kvm_rsi_read(vcpu); params[4] = (u32)kvm_rdi_read(vcpu); params[5] = (u32)kvm_rbp_read(vcpu); } #ifdef CONFIG_X86_64 else { params[0] = (u64)kvm_rdi_read(vcpu); params[1] = (u64)kvm_rsi_read(vcpu); params[2] = (u64)kvm_rdx_read(vcpu); params[3] = (u64)kvm_r10_read(vcpu); params[4] = (u64)kvm_r8_read(vcpu); params[5] = (u64)kvm_r9_read(vcpu); } #endif cpl = static_call(kvm_x86_get_cpl)(vcpu); trace_kvm_xen_hypercall(cpl, input, params[0], params[1], params[2], params[3], params[4], params[5]); /* * Only allow hypercall acceleration for CPL0. The rare hypercalls that * are permitted in guest userspace can be handled by the VMM. */ if (unlikely(cpl > 0)) goto handle_in_userspace; switch (input) { case __HYPERVISOR_xen_version: if (params[0] == XENVER_version && vcpu->kvm->arch.xen.xen_version) { r = vcpu->kvm->arch.xen.xen_version; handled = true; } break; case __HYPERVISOR_event_channel_op: if (params[0] == EVTCHNOP_send) handled = kvm_xen_hcall_evtchn_send(vcpu, params[1], &r); break; case __HYPERVISOR_sched_op: handled = kvm_xen_hcall_sched_op(vcpu, longmode, params[0], params[1], &r); break; case __HYPERVISOR_vcpu_op: handled = kvm_xen_hcall_vcpu_op(vcpu, longmode, params[0], params[1], params[2], &r); break; case __HYPERVISOR_set_timer_op: { u64 timeout = params[0]; /* In 32-bit mode, the 64-bit timeout is in two 32-bit params. */ if (!longmode) timeout |= params[1] << 32; handled = kvm_xen_hcall_set_timer_op(vcpu, timeout, &r); break; } default: break; } if (handled) return kvm_xen_hypercall_set_result(vcpu, r); handle_in_userspace: vcpu->run->exit_reason = KVM_EXIT_XEN; vcpu->run->xen.type = KVM_EXIT_XEN_HCALL; vcpu->run->xen.u.hcall.longmode = longmode; vcpu->run->xen.u.hcall.cpl = cpl; vcpu->run->xen.u.hcall.input = input; vcpu->run->xen.u.hcall.params[0] = params[0]; vcpu->run->xen.u.hcall.params[1] = params[1]; vcpu->run->xen.u.hcall.params[2] = params[2]; vcpu->run->xen.u.hcall.params[3] = params[3]; vcpu->run->xen.u.hcall.params[4] = params[4]; vcpu->run->xen.u.hcall.params[5] = params[5]; vcpu->arch.xen.hypercall_rip = kvm_get_linear_rip(vcpu); vcpu->arch.complete_userspace_io = kvm_xen_hypercall_complete_userspace; return 0; } static void kvm_xen_check_poller(struct kvm_vcpu *vcpu, int port) { int poll_evtchn = vcpu->arch.xen.poll_evtchn; if ((poll_evtchn == port || poll_evtchn == -1) && test_and_clear_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask)) { kvm_make_request(KVM_REQ_UNBLOCK, vcpu); kvm_vcpu_kick(vcpu); } } /* * The return value from this function is propagated to kvm_set_irq() API, * so it returns: * < 0 Interrupt was ignored (masked or not delivered for other reasons) * = 0 Interrupt was coalesced (previous irq is still pending) * > 0 Number of CPUs interrupt was delivered to * * It is also called directly from kvm_arch_set_irq_inatomic(), where the * only check on its return value is a comparison with -EWOULDBLOCK'. */ int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe, struct kvm *kvm) { struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache; struct kvm_vcpu *vcpu; unsigned long *pending_bits, *mask_bits; unsigned long flags; int port_word_bit; bool kick_vcpu = false; int vcpu_idx, idx, rc; vcpu_idx = READ_ONCE(xe->vcpu_idx); if (vcpu_idx >= 0) vcpu = kvm_get_vcpu(kvm, vcpu_idx); else { vcpu = kvm_get_vcpu_by_id(kvm, xe->vcpu_id); if (!vcpu) return -EINVAL; WRITE_ONCE(xe->vcpu_idx, vcpu->vcpu_idx); } if (!vcpu->arch.xen.vcpu_info_cache.active) return -EINVAL; if (xe->port >= max_evtchn_port(kvm)) return -EINVAL; rc = -EWOULDBLOCK; idx = srcu_read_lock(&kvm->srcu); read_lock_irqsave(&gpc->lock, flags); if (!kvm_gfn_to_pfn_cache_check(kvm, gpc, gpc->gpa, PAGE_SIZE)) goto out_rcu; if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) { struct shared_info *shinfo = gpc->khva; pending_bits = (unsigned long *)&shinfo->evtchn_pending; mask_bits = (unsigned long *)&shinfo->evtchn_mask; port_word_bit = xe->port / 64; } else { struct compat_shared_info *shinfo = gpc->khva; pending_bits = (unsigned long *)&shinfo->evtchn_pending; mask_bits = (unsigned long *)&shinfo->evtchn_mask; port_word_bit = xe->port / 32; } /* * If this port wasn't already set, and if it isn't masked, then * we try to set the corresponding bit in the in-kernel shadow of * evtchn_pending_sel for the target vCPU. And if *that* wasn't * already set, then we kick the vCPU in question to write to the * *real* evtchn_pending_sel in its own guest vcpu_info struct. */ if (test_and_set_bit(xe->port, pending_bits)) { rc = 0; /* It was already raised */ } else if (test_bit(xe->port, mask_bits)) { rc = -ENOTCONN; /* Masked */ kvm_xen_check_poller(vcpu, xe->port); } else { rc = 1; /* Delivered to the bitmap in shared_info. */ /* Now switch to the vCPU's vcpu_info to set the index and pending_sel */ read_unlock_irqrestore(&gpc->lock, flags); gpc = &vcpu->arch.xen.vcpu_info_cache; read_lock_irqsave(&gpc->lock, flags); if (!kvm_gfn_to_pfn_cache_check(kvm, gpc, gpc->gpa, sizeof(struct vcpu_info))) { /* * Could not access the vcpu_info. Set the bit in-kernel * and prod the vCPU to deliver it for itself. */ if (!test_and_set_bit(port_word_bit, &vcpu->arch.xen.evtchn_pending_sel)) kick_vcpu = true; goto out_rcu; } if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) { struct vcpu_info *vcpu_info = gpc->khva; if (!test_and_set_bit(port_word_bit, &vcpu_info->evtchn_pending_sel)) { WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1); kick_vcpu = true; } } else { struct compat_vcpu_info *vcpu_info = gpc->khva; if (!test_and_set_bit(port_word_bit, (unsigned long *)&vcpu_info->evtchn_pending_sel)) { WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1); kick_vcpu = true; } } /* For the per-vCPU lapic vector, deliver it as MSI. */ if (kick_vcpu && vcpu->arch.xen.upcall_vector) { kvm_xen_inject_vcpu_vector(vcpu); kick_vcpu = false; } } out_rcu: read_unlock_irqrestore(&gpc->lock, flags); srcu_read_unlock(&kvm->srcu, idx); if (kick_vcpu) { kvm_make_request(KVM_REQ_UNBLOCK, vcpu); kvm_vcpu_kick(vcpu); } return rc; } static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm) { bool mm_borrowed = false; int rc; rc = kvm_xen_set_evtchn_fast(xe, kvm); if (rc != -EWOULDBLOCK) return rc; if (current->mm != kvm->mm) { /* * If not on a thread which already belongs to this KVM, * we'd better be in the irqfd workqueue. */ if (WARN_ON_ONCE(current->mm)) return -EINVAL; kthread_use_mm(kvm->mm); mm_borrowed = true; } /* * For the irqfd workqueue, using the main kvm->lock mutex is * fine since this function is invoked from kvm_set_irq() with * no other lock held, no srcu. In future if it will be called * directly from a vCPU thread (e.g. on hypercall for an IPI) * then it may need to switch to using a leaf-node mutex for * serializing the shared_info mapping. */ mutex_lock(&kvm->lock); /* * It is theoretically possible for the page to be unmapped * and the MMU notifier to invalidate the shared_info before * we even get to use it. In that case, this looks like an * infinite loop. It was tempting to do it via the userspace * HVA instead... but that just *hides* the fact that it's * an infinite loop, because if a fault occurs and it waits * for the page to come back, it can *still* immediately * fault and have to wait again, repeatedly. * * Conversely, the page could also have been reinstated by * another thread before we even obtain the mutex above, so * check again *first* before remapping it. */ do { struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache; int idx; rc = kvm_xen_set_evtchn_fast(xe, kvm); if (rc != -EWOULDBLOCK) break; idx = srcu_read_lock(&kvm->srcu); rc = kvm_gfn_to_pfn_cache_refresh(kvm, gpc, gpc->gpa, PAGE_SIZE); srcu_read_unlock(&kvm->srcu, idx); } while(!rc); mutex_unlock(&kvm->lock); if (mm_borrowed) kthread_unuse_mm(kvm->mm); return rc; } /* This is the version called from kvm_set_irq() as the .set function */ static int evtchn_set_fn(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm, int irq_source_id, int level, bool line_status) { if (!level) return -EINVAL; return kvm_xen_set_evtchn(&e->xen_evtchn, kvm); } /* * Set up an event channel interrupt from the KVM IRQ routing table. * Used for e.g. PIRQ from passed through physical devices. */ int kvm_xen_setup_evtchn(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e, const struct kvm_irq_routing_entry *ue) { struct kvm_vcpu *vcpu; if (ue->u.xen_evtchn.port >= max_evtchn_port(kvm)) return -EINVAL; /* We only support 2 level event channels for now */ if (ue->u.xen_evtchn.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL) return -EINVAL; /* * Xen gives us interesting mappings from vCPU index to APIC ID, * which means kvm_get_vcpu_by_id() has to iterate over all vCPUs * to find it. Do that once at setup time, instead of every time. * But beware that on live update / live migration, the routing * table might be reinstated before the vCPU threads have finished * recreating their vCPUs. */ vcpu = kvm_get_vcpu_by_id(kvm, ue->u.xen_evtchn.vcpu); if (vcpu) e->xen_evtchn.vcpu_idx = vcpu->vcpu_idx; else e->xen_evtchn.vcpu_idx = -1; e->xen_evtchn.port = ue->u.xen_evtchn.port; e->xen_evtchn.vcpu_id = ue->u.xen_evtchn.vcpu; e->xen_evtchn.priority = ue->u.xen_evtchn.priority; e->set = evtchn_set_fn; return 0; } /* * Explicit event sending from userspace with KVM_XEN_HVM_EVTCHN_SEND ioctl. */ int kvm_xen_hvm_evtchn_send(struct kvm *kvm, struct kvm_irq_routing_xen_evtchn *uxe) { struct kvm_xen_evtchn e; int ret; if (!uxe->port || uxe->port >= max_evtchn_port(kvm)) return -EINVAL; /* We only support 2 level event channels for now */ if (uxe->priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL) return -EINVAL; e.port = uxe->port; e.vcpu_id = uxe->vcpu; e.vcpu_idx = -1; e.priority = uxe->priority; ret = kvm_xen_set_evtchn(&e, kvm); /* * None of that 'return 1 if it actually got delivered' nonsense. * We don't care if it was masked (-ENOTCONN) either. */ if (ret > 0 || ret == -ENOTCONN) ret = 0; return ret; } /* * Support for *outbound* event channel events via the EVTCHNOP_send hypercall. */ struct evtchnfd { u32 send_port; u32 type; union { struct kvm_xen_evtchn port; struct { u32 port; /* zero */ struct eventfd_ctx *ctx; } eventfd; } deliver; }; /* * Update target vCPU or priority for a registered sending channel. */ static int kvm_xen_eventfd_update(struct kvm *kvm, struct kvm_xen_hvm_attr *data) { u32 port = data->u.evtchn.send_port; struct evtchnfd *evtchnfd; if (!port || port >= max_evtchn_port(kvm)) return -EINVAL; mutex_lock(&kvm->lock); evtchnfd = idr_find(&kvm->arch.xen.evtchn_ports, port); mutex_unlock(&kvm->lock); if (!evtchnfd) return -ENOENT; /* For an UPDATE, nothing may change except the priority/vcpu */ if (evtchnfd->type != data->u.evtchn.type) return -EINVAL; /* * Port cannot change, and if it's zero that was an eventfd * which can't be changed either. */ if (!evtchnfd->deliver.port.port || evtchnfd->deliver.port.port != data->u.evtchn.deliver.port.port) return -EINVAL; /* We only support 2 level event channels for now */ if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL) return -EINVAL; mutex_lock(&kvm->lock); evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority; if (evtchnfd->deliver.port.vcpu_id != data->u.evtchn.deliver.port.vcpu) { evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu; evtchnfd->deliver.port.vcpu_idx = -1; } mutex_unlock(&kvm->lock); return 0; } /* * Configure the target (eventfd or local port delivery) for sending on * a given event channel. */ static int kvm_xen_eventfd_assign(struct kvm *kvm, struct kvm_xen_hvm_attr *data) { u32 port = data->u.evtchn.send_port; struct eventfd_ctx *eventfd = NULL; struct evtchnfd *evtchnfd = NULL; int ret = -EINVAL; if (!port || port >= max_evtchn_port(kvm)) return -EINVAL; evtchnfd = kzalloc(sizeof(struct evtchnfd), GFP_KERNEL); if (!evtchnfd) return -ENOMEM; switch(data->u.evtchn.type) { case EVTCHNSTAT_ipi: /* IPI must map back to the same port# */ if (data->u.evtchn.deliver.port.port != data->u.evtchn.send_port) goto out_noeventfd; /* -EINVAL */ break; case EVTCHNSTAT_interdomain: if (data->u.evtchn.deliver.port.port) { if (data->u.evtchn.deliver.port.port >= max_evtchn_port(kvm)) goto out_noeventfd; /* -EINVAL */ } else { eventfd = eventfd_ctx_fdget(data->u.evtchn.deliver.eventfd.fd); if (IS_ERR(eventfd)) { ret = PTR_ERR(eventfd); goto out_noeventfd; } } break; case EVTCHNSTAT_virq: case EVTCHNSTAT_closed: case EVTCHNSTAT_unbound: case EVTCHNSTAT_pirq: default: /* Unknown event channel type */ goto out; /* -EINVAL */ } evtchnfd->send_port = data->u.evtchn.send_port; evtchnfd->type = data->u.evtchn.type; if (eventfd) { evtchnfd->deliver.eventfd.ctx = eventfd; } else { /* We only support 2 level event channels for now */ if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL) goto out; /* -EINVAL; */ evtchnfd->deliver.port.port = data->u.evtchn.deliver.port.port; evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu; evtchnfd->deliver.port.vcpu_idx = -1; evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority; } mutex_lock(&kvm->lock); ret = idr_alloc(&kvm->arch.xen.evtchn_ports, evtchnfd, port, port + 1, GFP_KERNEL); mutex_unlock(&kvm->lock); if (ret >= 0) return 0; if (ret == -ENOSPC) ret = -EEXIST; out: if (eventfd) eventfd_ctx_put(eventfd); out_noeventfd: kfree(evtchnfd); return ret; } static int kvm_xen_eventfd_deassign(struct kvm *kvm, u32 port) { struct evtchnfd *evtchnfd; mutex_lock(&kvm->lock); evtchnfd = idr_remove(&kvm->arch.xen.evtchn_ports, port); mutex_unlock(&kvm->lock); if (!evtchnfd) return -ENOENT; if (kvm) synchronize_srcu(&kvm->srcu); if (!evtchnfd->deliver.port.port) eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx); kfree(evtchnfd); return 0; } static int kvm_xen_eventfd_reset(struct kvm *kvm) { struct evtchnfd *evtchnfd; int i; mutex_lock(&kvm->lock); idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) { idr_remove(&kvm->arch.xen.evtchn_ports, evtchnfd->send_port); synchronize_srcu(&kvm->srcu); if (!evtchnfd->deliver.port.port) eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx); kfree(evtchnfd); } mutex_unlock(&kvm->lock); return 0; } static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data) { u32 port = data->u.evtchn.send_port; if (data->u.evtchn.flags == KVM_XEN_EVTCHN_RESET) return kvm_xen_eventfd_reset(kvm); if (!port || port >= max_evtchn_port(kvm)) return -EINVAL; if (data->u.evtchn.flags == KVM_XEN_EVTCHN_DEASSIGN) return kvm_xen_eventfd_deassign(kvm, port); if (data->u.evtchn.flags == KVM_XEN_EVTCHN_UPDATE) return kvm_xen_eventfd_update(kvm, data); if (data->u.evtchn.flags) return -EINVAL; return kvm_xen_eventfd_assign(kvm, data); } static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r) { struct evtchnfd *evtchnfd; struct evtchn_send send; gpa_t gpa; int idx; idx = srcu_read_lock(&vcpu->kvm->srcu); gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL); srcu_read_unlock(&vcpu->kvm->srcu, idx); if (!gpa || kvm_vcpu_read_guest(vcpu, gpa, &send, sizeof(send))) { *r = -EFAULT; return true; } /* The evtchn_ports idr is protected by vcpu->kvm->srcu */ evtchnfd = idr_find(&vcpu->kvm->arch.xen.evtchn_ports, send.port); if (!evtchnfd) return false; if (evtchnfd->deliver.port.port) { int ret = kvm_xen_set_evtchn(&evtchnfd->deliver.port, vcpu->kvm); if (ret < 0 && ret != -ENOTCONN) return false; } else { eventfd_signal(evtchnfd->deliver.eventfd.ctx, 1); } *r = 0; return true; } void kvm_xen_init_vcpu(struct kvm_vcpu *vcpu) { vcpu->arch.xen.vcpu_id = vcpu->vcpu_idx; vcpu->arch.xen.poll_evtchn = 0; timer_setup(&vcpu->arch.xen.poll_timer, cancel_evtchn_poll, 0); kvm_gpc_init(&vcpu->arch.xen.runstate_cache); kvm_gpc_init(&vcpu->arch.xen.runstate2_cache); kvm_gpc_init(&vcpu->arch.xen.vcpu_info_cache); kvm_gpc_init(&vcpu->arch.xen.vcpu_time_info_cache); } void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu) { if (kvm_xen_timer_enabled(vcpu)) kvm_xen_stop_timer(vcpu); kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.runstate_cache); kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.runstate2_cache); kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.vcpu_info_cache); kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.vcpu_time_info_cache); del_timer_sync(&vcpu->arch.xen.poll_timer); } void kvm_xen_init_vm(struct kvm *kvm) { idr_init(&kvm->arch.xen.evtchn_ports); kvm_gpc_init(&kvm->arch.xen.shinfo_cache); } void kvm_xen_destroy_vm(struct kvm *kvm) { struct evtchnfd *evtchnfd; int i; kvm_gpc_deactivate(kvm, &kvm->arch.xen.shinfo_cache); idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) { if (!evtchnfd->deliver.port.port) eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx); kfree(evtchnfd); } idr_destroy(&kvm->arch.xen.evtchn_ports); if (kvm->arch.xen_hvm_config.msr) static_branch_slow_dec_deferred(&kvm_xen_enabled); }