diff options
Diffstat (limited to 'arch/x86/kvm/xen.c')
| -rw-r--r-- | arch/x86/kvm/xen.c | 1390 |
1 files changed, 1256 insertions, 134 deletions
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index dff2bdf9507a..2dae413bd62a 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -9,52 +9,100 @@ #include "x86.h" #include "xen.h" #include "hyperv.h" +#include "lapic.h" +#include <linux/eventfd.h> #include <linux/kvm_host.h> #include <linux/sched/stat.h> #include <trace/events/kvm.h> #include <xen/interface/xen.h> #include <xen/interface/vcpu.h> +#include <xen/interface/version.h> +#include <xen/interface/event_channel.h> +#include <xen/interface/sched.h> #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); - int wc_ofs, sec_hi_ofs; + u32 *wc_sec_hi; + u32 wc_version; + u64 wall_nsec; int ret = 0; int idx = srcu_read_lock(&kvm->srcu); - if (kvm_is_error_hva(gfn_to_hva(kvm, gfn))) { - ret = -EFAULT; + if (gfn == GPA_INVALID) { + kvm_gpc_deactivate(kvm, gpc); goto out; } - kvm->arch.xen.shinfo_gfn = gfn; + + 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); - /* 32-bit location by default */ - wc_ofs = offsetof(struct compat_shared_info, wc); - sec_hi_ofs = offsetof(struct compat_shared_info, arch.wc_sec_hi); - #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 (kvm->arch.xen.long_mode) { - wc_ofs = offsetof(struct shared_info, wc); - sec_hi_ofs = offsetof(struct shared_info, wc_sec_hi); - } + 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_write_wall_clock(kvm, gpa + wc_ofs, sec_hi_ofs - wc_ofs); kvm_make_all_cpus_request(kvm, KVM_REQ_MASTERCLOCK_UPDATE); out: @@ -62,6 +110,66 @@ out: 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(struct kvm_vcpu *v, int state) { struct kvm_vcpu_xen *vx = &v->arch.xen; @@ -93,49 +201,76 @@ static void kvm_xen_update_runstate(struct kvm_vcpu *v, int state) void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, int state) { struct kvm_vcpu_xen *vx = &v->arch.xen; - uint64_t state_entry_time; - unsigned int offset; + struct gfn_to_pfn_cache *gpc = &vx->runstate_cache; + uint64_t *user_times; + unsigned long flags; + size_t user_len; + int *user_state; kvm_xen_update_runstate(v, state); - if (!vx->runstate_set) + if (!vx->runstate_cache.active) return; - BUILD_BUG_ON(sizeof(struct compat_vcpu_runstate_info) != 0x2c); + if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) + user_len = sizeof(struct vcpu_runstate_info); + else + user_len = sizeof(struct compat_vcpu_runstate_info); + + read_lock_irqsave(&gpc->lock, flags); + while (!kvm_gfn_to_pfn_cache_check(v->kvm, gpc, gpc->gpa, + user_len)) { + read_unlock_irqrestore(&gpc->lock, flags); + + /* When invoked from kvm_sched_out() we cannot sleep */ + if (state == RUNSTATE_runnable) + return; + + if (kvm_gfn_to_pfn_cache_refresh(v->kvm, gpc, gpc->gpa, user_len)) + return; + + read_lock_irqsave(&gpc->lock, flags); + } - offset = offsetof(struct compat_vcpu_runstate_info, state_entry_time); -#ifdef CONFIG_X86_64 /* - * The only difference is alignment of uint64_t in 32-bit. - * So the first field 'state' is accessed directly using - * offsetof() (where its offset happens to be zero), while the - * remaining fields which are all uint64_t, start at 'offset' - * which we tweak here by adding 4. + * 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); + BUILD_BUG_ON(sizeof(struct compat_vcpu_runstate_info) != 0x2c); +#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) - offset = offsetof(struct vcpu_runstate_info, state_entry_time); #endif + + user_state = gpc->khva; + + if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) + user_times = gpc->khva + offsetof(struct vcpu_runstate_info, + state_entry_time); + else + user_times = gpc->khva + offsetof(struct compat_vcpu_runstate_info, + state_entry_time); + /* * 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)); + sizeof(user_times[0])); BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state_entry_time) != - sizeof(state_entry_time)); + sizeof(user_times[0])); - if (kvm_write_guest_offset_cached(v->kvm, &v->arch.xen.runstate_cache, - &state_entry_time, offset, - sizeof(state_entry_time))) - return; + user_times[0] = vx->runstate_entry_time | XEN_RUNSTATE_UPDATE; smp_wmb(); /* @@ -149,11 +284,7 @@ void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, int state) BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state) != sizeof(vx->current_runstate)); - if (kvm_write_guest_offset_cached(v->kvm, &v->arch.xen.runstate_cache, - &vx->current_runstate, - offsetof(struct vcpu_runstate_info, state), - sizeof(vx->current_runstate))) - return; + *user_state = vx->current_runstate; /* * Write the actual runstate times immediately after the @@ -168,38 +299,114 @@ void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, int state) BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) != sizeof(vx->runstate_times)); - if (kvm_write_guest_offset_cached(v->kvm, &v->arch.xen.runstate_cache, - &vx->runstate_times[0], - offset + sizeof(u64), - sizeof(vx->runstate_times))) - return; - + memcpy(user_times + 1, vx->runstate_times, sizeof(vx->runstate_times)); smp_wmb(); /* * Finally, clear the XEN_RUNSTATE_UPDATE bit in the guest's * runstate_entry_time field. */ + user_times[0] &= ~XEN_RUNSTATE_UPDATE; + smp_wmb(); + + read_unlock_irqrestore(&gpc->lock, flags); - state_entry_time &= ~XEN_RUNSTATE_UPDATE; - if (kvm_write_guest_offset_cached(v->kvm, &v->arch.xen.runstate_cache, - &state_entry_time, offset, - sizeof(state_entry_time))) + mark_page_dirty_in_slot(v->kvm, gpc->memslot, gpc->gpa >> PAGE_SHIFT); +} + +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) { - int err; + 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. */ - struct gfn_to_hva_cache *ghc = &v->arch.xen.vcpu_info_cache; - struct kvm_memslots *slots = kvm_memslots(v->kvm); - 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) != @@ -209,37 +416,35 @@ int __kvm_xen_has_interrupt(struct kvm_vcpu *v) 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 (likely(slots->generation == ghc->generation && - !kvm_is_error_hva(ghc->hva) && ghc->memslot)) { - /* Fast path */ - pagefault_disable(); - err = __get_user(rc, (u8 __user *)ghc->hva + offset); - pagefault_enable(); - if (!err) - return rc; - } - - /* Slow path */ + 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; + /* + * 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; - kvm_read_guest_offset_cached(v->kvm, ghc, &rc, offset, - sizeof(rc)); + 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; } @@ -247,42 +452,51 @@ 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 { + 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: - if (data->u.shared_info.gfn == GPA_INVALID) { - kvm->arch.xen.shinfo_gfn = GPA_INVALID; - r = 0; - break; - } + 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; } - mutex_unlock(&kvm->lock); return r; } @@ -299,7 +513,10 @@ int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) break; case KVM_XEN_ATTR_TYPE_SHARED_INFO: - data->u.shared_info.gfn = kvm->arch.xen.shinfo_gfn; + 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; @@ -308,6 +525,11 @@ int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) r = 0; break; + case KVM_XEN_ATTR_TYPE_XEN_VERSION: + data->u.xen_version = kvm->arch.xen.xen_version; + r = 0; + break; + default: break; } @@ -332,36 +554,34 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) offsetof(struct compat_vcpu_info, time)); if (data->u.gpa == GPA_INVALID) { - vcpu->arch.xen.vcpu_info_set = false; + kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.vcpu_info_cache); r = 0; 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; + 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) { - vcpu->arch.xen.vcpu_time_info_set = false; + kvm_gpc_deactivate(vcpu->kvm, + &vcpu->arch.xen.vcpu_time_info_cache); r = 0; 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; + 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: @@ -370,18 +590,15 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) break; } if (data->u.gpa == GPA_INVALID) { - vcpu->arch.xen.runstate_set = false; + kvm_gpc_deactivate(vcpu->kvm, + &vcpu->arch.xen.runstate_cache); r = 0; 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; - } + r = kvm_gpc_activate(vcpu->kvm, &vcpu->arch.xen.runstate_cache, + NULL, KVM_HOST_USES_PFN, data->u.gpa, + sizeof(struct vcpu_runstate_info)); break; case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT: @@ -479,6 +696,47 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) 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; } @@ -496,7 +754,7 @@ int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) switch (data->type) { case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO: - if (vcpu->arch.xen.vcpu_info_set) + if (vcpu->arch.xen.vcpu_info_cache.active) data->u.gpa = vcpu->arch.xen.vcpu_info_cache.gpa; else data->u.gpa = GPA_INVALID; @@ -504,7 +762,7 @@ int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) break; case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO: - if (vcpu->arch.xen.vcpu_time_info_set) + 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; @@ -516,7 +774,7 @@ int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) r = -EOPNOTSUPP; break; } - if (vcpu->arch.xen.runstate_set) { + if (vcpu->arch.xen.runstate_cache.active) { data->u.gpa = vcpu->arch.xen.runstate_cache.gpa; r = 0; } @@ -554,6 +812,23 @@ int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) 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; } @@ -589,7 +864,7 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data) instructions[0] = 0xb8; /* vmcall / vmmcall */ - kvm_x86_ops.patch_hypercall(vcpu, instructions + 5); + static_call(kvm_x86_patch_hypercall)(vcpu, instructions + 5); /* ret */ instructions[8] = 0xc3; @@ -634,7 +909,11 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data) int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc) { - if (xhc->flags & ~KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL) + /* 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; /* @@ -659,17 +938,6 @@ int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc) return 0; } -void kvm_xen_init_vm(struct kvm *kvm) -{ - kvm->arch.xen.shinfo_gfn = GPA_INVALID; -} - -void kvm_xen_destroy_vm(struct kvm *kvm) -{ - 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); @@ -686,10 +954,267 @@ static int kvm_xen_hypercall_complete_userspace(struct kvm_vcpu *vcpu) return kvm_xen_hypercall_set_result(vcpu, run->xen.u.hcall.result); } +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 (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]; + u64 input, params[6], r = -ENOSYS; + bool handled = false; input = (u64)kvm_register_read(vcpu, VCPU_REGS_RAX); @@ -720,10 +1245,44 @@ int kvm_xen_hypercall(struct kvm_vcpu *vcpu) trace_kvm_xen_hypercall(input, params[0], params[1], params[2], params[3], params[4], params[5]); + 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); + 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 = kvm_x86_ops.get_cpl(vcpu); + 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]; @@ -737,3 +1296,566 @@ int kvm_xen_hypercall(struct kvm_vcpu *vcpu) 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; +} + +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.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.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); +} |