// 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 #include #include #include #include #include #include "trace.h" 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_gfn_to_pfn_cache_destroy(kvm, gpc); goto out; } do { ret = kvm_gfn_to_pfn_cache_init(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; } static 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; } void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, int state) { struct kvm_vcpu_xen *vx = &v->arch.xen; struct gfn_to_hva_cache *ghc = &vx->runstate_cache; struct kvm_memslots *slots = kvm_memslots(v->kvm); bool atomic = (state == RUNSTATE_runnable); uint64_t state_entry_time; int __user *user_state; uint64_t __user *user_times; kvm_xen_update_runstate(v, state); if (!vx->runstate_set) return; if (unlikely(slots->generation != ghc->generation || kvm_is_error_hva(ghc->hva)) && kvm_gfn_to_hva_cache_init(v->kvm, ghc, ghc->gpa, ghc->len)) return; /* We made sure it fits in a single page */ BUG_ON(!ghc->memslot); if (atomic) pagefault_disable(); /* * The only difference between 32-bit and 64-bit versions of the * runstate struct us 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'. * * So we use 'int __user *user_state' to point to the state field, * and 'uint64_t __user *user_times' for runstate_entry_time. So * the actual array of time[] in each state starts at user_times[1]. */ BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) != 0); BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state) != 0); user_state = (int __user *)ghc->hva; BUILD_BUG_ON(sizeof(struct compat_vcpu_runstate_info) != 0x2c); user_times = (uint64_t __user *)(ghc->hva + offsetof(struct compat_vcpu_runstate_info, state_entry_time)); #ifdef CONFIG_X86_64 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); if (v->kvm->arch.xen.long_mode) user_times = (uint64_t __user *)(ghc->hva + offsetof(struct vcpu_runstate_info, state_entry_time)); #endif /* * First write the updated state_entry_time at the appropriate * location determined by 'offset'. */ state_entry_time = vx->runstate_entry_time; state_entry_time |= XEN_RUNSTATE_UPDATE; BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state_entry_time) != sizeof(state_entry_time)); BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state_entry_time) != sizeof(state_entry_time)); if (__put_user(state_entry_time, user_times)) goto out; smp_wmb(); /* * Next, write the new runstate. This is in the *same* place * for 32-bit and 64-bit guests, asserted here for paranoia. */ 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)); if (__put_user(vx->current_runstate, user_state)) goto out; /* * Write the actual runstate times immediately after the * runstate_entry_time. */ BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) != offsetof(struct vcpu_runstate_info, time) - sizeof(u64)); BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state_entry_time) != offsetof(struct compat_vcpu_runstate_info, time) - sizeof(u64)); 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 (__copy_to_user(user_times + 1, vx->runstate_times, sizeof(vx->runstate_times))) goto out; smp_wmb(); /* * Finally, clear the XEN_RUNSTATE_UPDATE bit in the guest's * runstate_entry_time field. */ state_entry_time &= ~XEN_RUNSTATE_UPDATE; __put_user(state_entry_time, user_times); smp_wmb(); out: mark_page_dirty_in_slot(v->kvm, ghc->memslot, ghc->gpa >> PAGE_SHIFT); if (atomic) pagefault_enable(); } int __kvm_xen_has_interrupt(struct kvm_vcpu *v) { unsigned long evtchn_pending_sel = READ_ONCE(v->arch.xen.evtchn_pending_sel); bool atomic = in_atomic() || !task_is_running(current); int err; 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. */ struct gfn_to_hva_cache *ghc = &v->arch.xen.vcpu_info_cache; struct kvm_memslots *slots = kvm_memslots(v->kvm); bool ghc_valid = slots->generation == ghc->generation && !kvm_is_error_hva(ghc->hva) && ghc->memslot; unsigned int offset = offsetof(struct vcpu_info, evtchn_upcall_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)); /* * For efficiency, this mirrors the checks for using the valid * cache in kvm_read_guest_offset_cached(), but just uses * __get_user() instead. And falls back to the slow path. */ if (!evtchn_pending_sel && ghc_valid) { /* Fast path */ pagefault_disable(); err = __get_user(rc, (u8 __user *)ghc->hva + offset); pagefault_enable(); if (!err) return rc; } /* Slow path */ /* * 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 (atomic) return 1; if (!ghc_valid) { err = kvm_gfn_to_hva_cache_init(v->kvm, ghc, ghc->gpa, ghc->len); if (err || !ghc->memslot) { /* * If this failed, userspace has screwed up the * vcpu_info mapping. No interrupts for you. */ return 0; } } /* * Now we have a valid (protected by srcu) userspace HVA in * ghc->hva which points to the struct vcpu_info. If there * are any bits in the in-kernel evtchn_pending_sel then * we need to write those to the guest vcpu_info and set * its evtchn_upcall_pending flag. If there aren't any bits * to add, we only want to *check* evtchn_upcall_pending. */ if (evtchn_pending_sel) { bool long_mode = v->kvm->arch.xen.long_mode; if (!user_access_begin((void __user *)ghc->hva, sizeof(struct vcpu_info))) return 0; if (IS_ENABLED(CONFIG_64BIT) && long_mode) { struct vcpu_info __user *vi = (void __user *)ghc->hva; /* Attempt to set the evtchn_pending_sel bits in the * guest, and if that succeeds then clear the same * bits in the in-kernel version. */ asm volatile("1:\t" LOCK_PREFIX "orq %0, %1\n" "\tnotq %0\n" "\t" LOCK_PREFIX "andq %0, %2\n" "2:\n" _ASM_EXTABLE_UA(1b, 2b) : "=r" (evtchn_pending_sel), "+m" (vi->evtchn_pending_sel), "+m" (v->arch.xen.evtchn_pending_sel) : "0" (evtchn_pending_sel)); } else { struct compat_vcpu_info __user *vi = (void __user *)ghc->hva; u32 evtchn_pending_sel32 = evtchn_pending_sel; /* Attempt to set the evtchn_pending_sel bits in the * guest, and if that succeeds then clear the same * bits in the in-kernel version. */ asm volatile("1:\t" LOCK_PREFIX "orl %0, %1\n" "\tnotl %0\n" "\t" LOCK_PREFIX "andl %0, %2\n" "2:\n" _ASM_EXTABLE_UA(1b, 2b) : "=r" (evtchn_pending_sel32), "+m" (vi->evtchn_pending_sel), "+m" (v->arch.xen.evtchn_pending_sel) : "0" (evtchn_pending_sel32)); } rc = 1; unsafe_put_user(rc, (u8 __user *)ghc->hva + offset, err); err: user_access_end(); mark_page_dirty_in_slot(v->kvm, ghc->memslot, ghc->gpa >> PAGE_SHIFT); } else { __get_user(rc, (u8 __user *)ghc->hva + offset); } return rc; } int kvm_xen_hvm_set_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: if (!IS_ENABLED(CONFIG_64BIT) && data->u.long_mode) { r = -EINVAL; } else { kvm->arch.xen.long_mode = !!data->u.long_mode; r = 0; } break; case KVM_XEN_ATTR_TYPE_SHARED_INFO: r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn); break; case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR: if (data->u.vector && data->u.vector < 0x10) r = -EINVAL; else { kvm->arch.xen.upcall_vector = data->u.vector; r = 0; } break; default: break; } mutex_unlock(&kvm->lock); 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; 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) { vcpu->arch.xen.vcpu_info_set = false; r = 0; break; } /* It must fit within a single page */ if ((data->u.gpa & ~PAGE_MASK) + sizeof(struct vcpu_info) > PAGE_SIZE) { r = -EINVAL; break; } r = kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.xen.vcpu_info_cache, data->u.gpa, sizeof(struct vcpu_info)); if (!r) { vcpu->arch.xen.vcpu_info_set = true; kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); } break; case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO: if (data->u.gpa == GPA_INVALID) { vcpu->arch.xen.vcpu_time_info_set = false; r = 0; break; } /* It must fit within a single page */ if ((data->u.gpa & ~PAGE_MASK) + sizeof(struct pvclock_vcpu_time_info) > PAGE_SIZE) { r = -EINVAL; break; } r = kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.xen.vcpu_time_info_cache, data->u.gpa, sizeof(struct pvclock_vcpu_time_info)); if (!r) { vcpu->arch.xen.vcpu_time_info_set = true; kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); } break; case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR: if (!sched_info_on()) { r = -EOPNOTSUPP; break; } if (data->u.gpa == GPA_INVALID) { vcpu->arch.xen.runstate_set = false; r = 0; break; } /* It must fit within a single page */ if ((data->u.gpa & ~PAGE_MASK) + sizeof(struct vcpu_runstate_info) > PAGE_SIZE) { r = -EINVAL; break; } r = kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.xen.runstate_cache, data->u.gpa, sizeof(struct vcpu_runstate_info)); if (!r) { vcpu->arch.xen.runstate_set = true; } 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; 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_set) 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_set) 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_set) { 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; 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) { if (xhc->flags & ~KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL) 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; } void kvm_xen_init_vm(struct kvm *kvm) { } void kvm_xen_destroy_vm(struct kvm *kvm) { kvm_gfn_to_pfn_cache_destroy(kvm, &kvm->arch.xen.shinfo_cache); if (kvm->arch.xen_hvm_config.msr) static_branch_slow_dec_deferred(&kvm_xen_enabled); } 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); } int kvm_xen_hypercall(struct kvm_vcpu *vcpu) { bool longmode; u64 input, params[6]; 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 trace_kvm_xen_hypercall(input, params[0], params[1], params[2], params[3], params[4], params[5]); 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 = static_call(kvm_x86_get_cpl)(vcpu); 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 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; } /* * This follows the 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 */ int kvm_xen_set_evtchn_fast(struct kvm_kernel_irq_routing_entry *e, 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 idx; int rc; vcpu = kvm_get_vcpu_by_id(kvm, e->xen_evtchn.vcpu); if (!vcpu) return -1; if (!vcpu->arch.xen.vcpu_info_set) return -1; if (e->xen_evtchn.port >= max_evtchn_port(kvm)) return -1; rc = -EWOULDBLOCK; 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; 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 = e->xen_evtchn.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 = e->xen_evtchn.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(e->xen_evtchn.port, pending_bits)) { rc = 0; /* It was already raised */ } else if (test_bit(e->xen_evtchn.port, mask_bits)) { rc = -1; /* Masked */ } else { rc = 1; /* Delivered. But was the vCPU waking already? */ if (!test_and_set_bit(port_word_bit, &vcpu->arch.xen.evtchn_pending_sel)) kick_vcpu = true; } out_rcu: srcu_read_unlock(&kvm->srcu, idx); read_unlock_irqrestore(&gpc->lock, flags); if (kick_vcpu) { kvm_make_request(KVM_REQ_EVENT, vcpu); kvm_vcpu_kick(vcpu); } 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) { bool mm_borrowed = false; int rc; if (!level) return -1; rc = kvm_xen_set_evtchn_fast(e, 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(e, 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; } int kvm_xen_setup_evtchn(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e, const struct kvm_irq_routing_entry *ue) { 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; e->xen_evtchn.port = ue->u.xen_evtchn.port; e->xen_evtchn.vcpu = ue->u.xen_evtchn.vcpu; e->xen_evtchn.priority = ue->u.xen_evtchn.priority; e->set = evtchn_set_fn; return 0; }