linux/arch/x86/kvm/xen.c
David Woodhouse 7a36d68065 KVM: x86/xen: fix recursive deadlock in timer injection
The fast-path timer delivery introduced a recursive locking deadlock
when userspace configures a timer which has already expired and is
delivered immediately. The call to kvm_xen_inject_timer_irqs() can
call to kvm_xen_set_evtchn() which may take kvm->arch.xen.xen_lock,
which is already held in kvm_xen_vcpu_get_attr().

 ============================================
 WARNING: possible recursive locking detected
 6.8.0-smp--5e10b4d51d77-drs #232 Tainted: G           O
 --------------------------------------------
 xen_shinfo_test/250013 is trying to acquire lock:
 ffff938c9930cc30 (&kvm->arch.xen.xen_lock){+.+.}-{3:3}, at: kvm_xen_set_evtchn+0x74/0x170 [kvm]

 but task is already holding lock:
 ffff938c9930cc30 (&kvm->arch.xen.xen_lock){+.+.}-{3:3}, at: kvm_xen_vcpu_get_attr+0x38/0x250 [kvm]

Now that the gfn_to_pfn_cache has its own self-sufficient locking, its
callers no longer need to ensure serialization, so just stop taking
kvm->arch.xen.xen_lock from kvm_xen_set_evtchn().

Fixes: 77c9b9dea4 ("KVM: x86/xen: Use fast path for Xen timer delivery")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Link: https://lore.kernel.org/r/20240227115648.3104-6-dwmw2@infradead.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-03-04 16:22:39 -08:00

2305 lines
63 KiB
C

// 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
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include "x86.h"
#include "xen.h"
#include "hyperv.h"
#include "irq.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 <asm/xen/cpuid.h>
#include <asm/pvclock.h>
#include "cpuid.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)
{
struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
struct pvclock_wall_clock *wc;
u32 *wc_sec_hi;
u32 wc_version;
u64 wall_nsec;
int ret = 0;
int idx = srcu_read_lock(&kvm->srcu);
read_lock_irq(&gpc->lock);
while (!kvm_gpc_check(gpc, PAGE_SIZE)) {
read_unlock_irq(&gpc->lock);
ret = kvm_gpc_refresh(gpc, PAGE_SIZE);
if (ret)
goto out;
read_lock_irq(&gpc->lock);
}
/*
* 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 = kvm_get_wall_clock_epoch(kvm);
/* 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, NSEC_PER_SEC);
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);
struct kvm_xen_evtchn e;
int rc;
if (atomic_read(&vcpu->arch.xen.timer_pending))
return HRTIMER_NORESTART;
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;
rc = kvm_xen_set_evtchn_fast(&e, vcpu->kvm);
if (rc != -EWOULDBLOCK) {
vcpu->arch.xen.timer_expires = 0;
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,
bool linux_wa)
{
int64_t kernel_now, delta;
uint64_t guest_now;
/*
* The guest provides the requested timeout in absolute nanoseconds
* of the KVM clock — as *it* sees it, based on the scaled TSC and
* the pvclock information provided by KVM.
*
* The kernel doesn't support hrtimers based on CLOCK_MONOTONIC_RAW
* so use CLOCK_MONOTONIC. In the timescales covered by timers, the
* difference won't matter much as there is no cumulative effect.
*
* Calculate the time for some arbitrary point in time around "now"
* in terms of both kvmclock and CLOCK_MONOTONIC. Calculate the
* delta between the kvmclock "now" value and the guest's requested
* timeout, apply the "Linux workaround" described below, and add
* the resulting delta to the CLOCK_MONOTONIC "now" value, to get
* the absolute CLOCK_MONOTONIC time at which the timer should
* fire.
*/
if (vcpu->arch.hv_clock.version && vcpu->kvm->arch.use_master_clock &&
static_cpu_has(X86_FEATURE_CONSTANT_TSC)) {
uint64_t host_tsc, guest_tsc;
if (!IS_ENABLED(CONFIG_64BIT) ||
!kvm_get_monotonic_and_clockread(&kernel_now, &host_tsc)) {
/*
* Don't fall back to get_kvmclock_ns() because it's
* broken; it has a systemic error in its results
* because it scales directly from host TSC to
* nanoseconds, and doesn't scale first to guest TSC
* and *then* to nanoseconds as the guest does.
*
* There is a small error introduced here because time
* continues to elapse between the ktime_get() and the
* subsequent rdtsc(). But not the systemic drift due
* to get_kvmclock_ns().
*/
kernel_now = ktime_get(); /* This is CLOCK_MONOTONIC */
host_tsc = rdtsc();
}
/* Calculate the guest kvmclock as the guest would do it. */
guest_tsc = kvm_read_l1_tsc(vcpu, host_tsc);
guest_now = __pvclock_read_cycles(&vcpu->arch.hv_clock,
guest_tsc);
} else {
/*
* Without CONSTANT_TSC, get_kvmclock_ns() is the only option.
*
* Also if the guest PV clock hasn't been set up yet, as is
* likely to be the case during migration when the vCPU has
* not been run yet. It would be possible to calculate the
* scaling factors properly in that case but there's not much
* point in doing so. The get_kvmclock_ns() drift accumulates
* over time, so it's OK to use it at startup. Besides, on
* migration there's going to be a little bit of skew in the
* precise moment at which timers fire anyway. Often they'll
* be in the "past" by the time the VM is running again after
* migration.
*/
guest_now = get_kvmclock_ns(vcpu->kvm);
kernel_now = ktime_get();
}
delta = guest_abs - 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, Xen 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). Emulate Xen's workaround when starting the
* timer in response to __HYPERVISOR_set_timer_op.
*/
if (linux_wa &&
unlikely((int64_t)guest_abs < 0 ||
(delta > 0 && (uint32_t) (delta >> 50) != 0))) {
delta = 100 * NSEC_PER_MSEC;
guest_abs = guest_now + delta;
}
/*
* Avoid races with the old timer firing. Checking timer_expires
* to avoid calling hrtimer_cancel() will only have false positives
* so is fine.
*/
if (vcpu->arch.xen.timer_expires)
hrtimer_cancel(&vcpu->arch.xen.timer);
atomic_set(&vcpu->arch.xen.timer_pending, 0);
vcpu->arch.xen.timer_expires = guest_abs;
if (delta <= 0)
xen_timer_callback(&vcpu->arch.xen.timer);
else
hrtimer_start(&vcpu->arch.xen.timer,
ktime_add_ns(kernel_now, delta),
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 = NULL;
uint64_t entry_time;
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.
*/
if (atomic) {
local_irq_save(flags);
if (!read_trylock(&gpc1->lock)) {
local_irq_restore(flags);
return;
}
} else {
read_lock_irqsave(&gpc1->lock, flags);
}
while (!kvm_gpc_check(gpc1, user_len1)) {
read_unlock_irqrestore(&gpc1->lock, flags);
/* When invoked from kvm_sched_out() we cannot sleep */
if (atomic)
return;
if (kvm_gpc_refresh(gpc1, 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;
if (v->kvm->arch.xen.runstate_update_flag)
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. Set a subclass on the
* gpc1 lock to make lockdep shut up about it.
*/
lock_set_subclass(&gpc1->lock.dep_map, 1, _THIS_IP_);
if (atomic) {
if (!read_trylock(&gpc2->lock)) {
read_unlock_irqrestore(&gpc1->lock, flags);
return;
}
} else {
read_lock(&gpc2->lock);
}
if (!kvm_gpc_check(gpc2, 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(gpc2, 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 (v->kvm->arch.xen.runstate_update_flag) {
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.
*/
entry_time = vx->runstate_entry_time;
if (update_bit) {
entry_time |= XEN_RUNSTATE_UPDATE;
*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] = entry_time;
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. */
if (update_bit) {
entry_time &= ~XEN_RUNSTATE_UPDATE;
*update_bit = entry_time >> 56;
smp_wmb();
}
if (user_len2) {
kvm_gpc_mark_dirty_in_slot(gpc2);
read_unlock(&gpc2->lock);
}
kvm_gpc_mark_dirty_in_slot(gpc1);
read_unlock_irqrestore(&gpc1->lock, flags);
}
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);
}
void kvm_xen_inject_vcpu_vector(struct kvm_vcpu *v)
{
struct kvm_lapic_irq irq = { };
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;
kvm_irq_delivery_to_apic(v->kvm, NULL, &irq, 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_gpc_check(gpc, sizeof(struct vcpu_info))) {
read_unlock_irqrestore(&gpc->lock, flags);
if (kvm_gpc_refresh(gpc, 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);
}
kvm_gpc_mark_dirty_in_slot(gpc);
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);
}
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_gpc_check(gpc, 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_gpc_refresh(gpc, 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->arch.xen.xen_lock);
kvm->arch.xen.long_mode = !!data->u.long_mode;
/*
* Re-initialize shared_info to put the wallclock in the
* correct place. Whilst it's not necessary to do this
* unless the mode is actually changed, it does no harm
* to make the call anyway.
*/
r = kvm->arch.xen.shinfo_cache.active ?
kvm_xen_shared_info_init(kvm) : 0;
mutex_unlock(&kvm->arch.xen.xen_lock);
}
break;
case KVM_XEN_ATTR_TYPE_SHARED_INFO:
case KVM_XEN_ATTR_TYPE_SHARED_INFO_HVA: {
int idx;
mutex_lock(&kvm->arch.xen.xen_lock);
idx = srcu_read_lock(&kvm->srcu);
if (data->type == KVM_XEN_ATTR_TYPE_SHARED_INFO) {
gfn_t gfn = data->u.shared_info.gfn;
if (gfn == KVM_XEN_INVALID_GFN) {
kvm_gpc_deactivate(&kvm->arch.xen.shinfo_cache);
r = 0;
} else {
r = kvm_gpc_activate(&kvm->arch.xen.shinfo_cache,
gfn_to_gpa(gfn), PAGE_SIZE);
}
} else {
void __user * hva = u64_to_user_ptr(data->u.shared_info.hva);
if (!PAGE_ALIGNED(hva) || !access_ok(hva, PAGE_SIZE)) {
r = -EINVAL;
} else if (!hva) {
kvm_gpc_deactivate(&kvm->arch.xen.shinfo_cache);
r = 0;
} else {
r = kvm_gpc_activate_hva(&kvm->arch.xen.shinfo_cache,
(unsigned long)hva, PAGE_SIZE);
}
}
srcu_read_unlock(&kvm->srcu, idx);
if (!r && kvm->arch.xen.shinfo_cache.active)
r = kvm_xen_shared_info_init(kvm);
mutex_unlock(&kvm->arch.xen.xen_lock);
break;
}
case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
if (data->u.vector && data->u.vector < 0x10)
r = -EINVAL;
else {
mutex_lock(&kvm->arch.xen.xen_lock);
kvm->arch.xen.upcall_vector = data->u.vector;
mutex_unlock(&kvm->arch.xen.xen_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->arch.xen.xen_lock);
kvm->arch.xen.xen_version = data->u.xen_version;
mutex_unlock(&kvm->arch.xen.xen_lock);
r = 0;
break;
case KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG:
if (!sched_info_on()) {
r = -EOPNOTSUPP;
break;
}
mutex_lock(&kvm->arch.xen.xen_lock);
kvm->arch.xen.runstate_update_flag = !!data->u.runstate_update_flag;
mutex_unlock(&kvm->arch.xen.xen_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->arch.xen.xen_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_gpc_is_gpa_active(&kvm->arch.xen.shinfo_cache))
data->u.shared_info.gfn = gpa_to_gfn(kvm->arch.xen.shinfo_cache.gpa);
else
data->u.shared_info.gfn = KVM_XEN_INVALID_GFN;
r = 0;
break;
case KVM_XEN_ATTR_TYPE_SHARED_INFO_HVA:
if (kvm_gpc_is_hva_active(&kvm->arch.xen.shinfo_cache))
data->u.shared_info.hva = kvm->arch.xen.shinfo_cache.uhva;
else
data->u.shared_info.hva = 0;
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;
case KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG:
if (!sched_info_on()) {
r = -EOPNOTSUPP;
break;
}
data->u.runstate_update_flag = kvm->arch.xen.runstate_update_flag;
r = 0;
break;
default:
break;
}
mutex_unlock(&kvm->arch.xen.xen_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->arch.xen.xen_lock);
idx = srcu_read_lock(&vcpu->kvm->srcu);
switch (data->type) {
case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO_HVA:
/* 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->type == KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO) {
if (data->u.gpa == KVM_XEN_INVALID_GPA) {
kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_info_cache);
r = 0;
break;
}
r = kvm_gpc_activate(&vcpu->arch.xen.vcpu_info_cache,
data->u.gpa, sizeof(struct vcpu_info));
} else {
if (data->u.hva == 0) {
kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_info_cache);
r = 0;
break;
}
r = kvm_gpc_activate_hva(&vcpu->arch.xen.vcpu_info_cache,
data->u.hva, 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 == KVM_XEN_INVALID_GPA) {
kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_time_info_cache);
r = 0;
break;
}
r = kvm_gpc_activate(&vcpu->arch.xen.vcpu_time_info_cache,
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 == KVM_XEN_INVALID_GPA) {
r = 0;
deactivate_out:
kvm_gpc_deactivate(&vcpu->arch.xen.runstate_cache);
kvm_gpc_deactivate(&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->arch.xen.runstate_cache,
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->arch.xen.runstate2_cache);
} else {
sz2 = sz - sz1;
BUG_ON((data->u.gpa + sz1) & ~PAGE_MASK);
r = kvm_gpc_activate(&vcpu->arch.xen.runstate2_cache,
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);
else if (vcpu->arch.xen.runstate_cache.active)
kvm_xen_update_runstate_guest(vcpu, false);
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, false);
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->arch.xen.xen_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->arch.xen.xen_lock);
switch (data->type) {
case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
if (kvm_gpc_is_gpa_active(&vcpu->arch.xen.vcpu_info_cache))
data->u.gpa = vcpu->arch.xen.vcpu_info_cache.gpa;
else
data->u.gpa = KVM_XEN_INVALID_GPA;
r = 0;
break;
case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO_HVA:
if (kvm_gpc_is_hva_active(&vcpu->arch.xen.vcpu_info_cache))
data->u.hva = vcpu->arch.xen.vcpu_info_cache.uhva;
else
data->u.hva = 0;
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 = KVM_XEN_INVALID_GPA;
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:
/*
* Ensure a consistent snapshot of state is captured, with a
* timer either being pending, or the event channel delivered
* to the corresponding bit in the shared_info. Not still
* lurking in the timer_pending flag for deferred delivery.
* Purely as an optimisation, if the timer_expires field is
* zero, that means the timer isn't active (or even in the
* timer_pending flag) and there is no need to cancel it.
*/
if (vcpu->arch.xen.timer_expires) {
hrtimer_cancel(&vcpu->arch.xen.timer);
kvm_xen_inject_timer_irqs(vcpu);
}
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;
/*
* The hrtimer may trigger and raise the IRQ immediately,
* while the returned state causes it to be set up and
* raised again on the destination system after migration.
* That's fine, as the guest won't even have had a chance
* to run and handle the interrupt. Asserting an already
* pending event channel is idempotent.
*/
if (vcpu->arch.xen.timer_expires)
hrtimer_start_expires(&vcpu->arch.xen.timer,
HRTIMER_MODE_ABS_HARD);
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->arch.xen.xen_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);
int r = 0;
mutex_lock(&kvm->arch.xen.xen_lock);
if (kvm->arch.xen.long_mode != lm) {
kvm->arch.xen.long_mode = lm;
/*
* Re-initialize shared_info to put the wallclock in the
* correct place.
*/
if (kvm->arch.xen.shinfo_cache.active &&
kvm_xen_shared_info_init(kvm))
r = 1;
}
mutex_unlock(&kvm->arch.xen.xen_lock);
if (r)
return r;
/*
* 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;
int ret;
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);
ret = kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE);
kfree(page);
if (ret)
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 |
KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE;
u32 old_flags;
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->arch.xen.xen_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);
old_flags = kvm->arch.xen_hvm_config.flags;
memcpy(&kvm->arch.xen_hvm_config, xhc, sizeof(*xhc));
mutex_unlock(&kvm->arch.xen.xen_lock);
if ((old_flags ^ xhc->flags) & KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE)
kvm_make_all_cpus_request(kvm, KVM_REQ_CLOCK_UPDATE);
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;
idx = srcu_read_lock(&kvm->srcu);
read_lock_irqsave(&gpc->lock, flags);
if (!kvm_gpc_check(gpc, 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:
read_unlock_irqrestore(&gpc->lock, flags);
srcu_read_unlock(&kvm->srcu, idx);
return ret;
}
static bool kvm_xen_schedop_poll(struct kvm_vcpu *vcpu, bool longmode,
u64 param, u64 *r)
{
struct sched_poll sched_poll;
evtchn_port_t port, *ports;
struct x86_exception e;
int i;
if (!lapic_in_kernel(vcpu) ||
!(vcpu->kvm->arch.xen_hvm_config.flags & KVM_XEN_HVM_CONFIG_EVTCHN_SEND))
return false;
if (IS_ENABLED(CONFIG_64BIT) && !longmode) {
struct compat_sched_poll sp32;
/* Sanity check that the compat struct definition is correct */
BUILD_BUG_ON(sizeof(sp32) != 16);
if (kvm_read_guest_virt(vcpu, param, &sp32, sizeof(sp32), &e)) {
*r = -EFAULT;
return true;
}
/*
* This is a 32-bit pointer to an array of evtchn_port_t which
* are uint32_t, so once it's converted no further compat
* handling is needed.
*/
sched_poll.ports = (void *)(unsigned long)(sp32.ports);
sched_poll.nr_ports = sp32.nr_ports;
sched_poll.timeout = sp32.timeout;
} else {
if (kvm_read_guest_virt(vcpu, param, &sched_poll,
sizeof(sched_poll), &e)) {
*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;
if (kvm_read_guest_virt(vcpu, (gva_t)sched_poll.ports, ports,
sched_poll.nr_ports * sizeof(*ports), &e)) {
*r = -EFAULT;
return true;
}
for (i = 0; i < sched_poll.nr_ports; i++) {
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;
struct x86_exception e;
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;
}
/*
* 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 (kvm_read_guest_virt(vcpu, param, &oneshot, longmode ? sizeof(oneshot) :
sizeof(struct compat_vcpu_set_singleshot_timer), &e)) {
*r = -EFAULT;
return true;
}
kvm_xen_start_timer(vcpu, oneshot.timeout_abs_ns, false);
*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)
kvm_xen_start_timer(vcpu, timeout, true);
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 (xe->port >= max_evtchn_port(kvm))
return -EINVAL;
rc = -EWOULDBLOCK;
idx = srcu_read_lock(&kvm->srcu);
read_lock_irqsave(&gpc->lock, flags);
if (!kvm_gpc_check(gpc, 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_gpc_check(gpc, 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;
}
/*
* 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_gpc_refresh(gpc, PAGE_SIZE);
srcu_read_unlock(&kvm->srcu, idx);
} while(!rc);
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;
int ret;
/* Protect writes to evtchnfd as well as the idr lookup. */
mutex_lock(&kvm->arch.xen.xen_lock);
evtchnfd = idr_find(&kvm->arch.xen.evtchn_ports, port);
ret = -ENOENT;
if (!evtchnfd)
goto out_unlock;
/* For an UPDATE, nothing may change except the priority/vcpu */
ret = -EINVAL;
if (evtchnfd->type != data->u.evtchn.type)
goto out_unlock;
/*
* 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)
goto out_unlock;
/* 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_unlock;
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;
}
ret = 0;
out_unlock:
mutex_unlock(&kvm->arch.xen.xen_lock);
return ret;
}
/*
* 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;
int ret = -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->arch.xen.xen_lock);
ret = idr_alloc(&kvm->arch.xen.evtchn_ports, evtchnfd, port, port + 1,
GFP_KERNEL);
mutex_unlock(&kvm->arch.xen.xen_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->arch.xen.xen_lock);
evtchnfd = idr_remove(&kvm->arch.xen.evtchn_ports, port);
mutex_unlock(&kvm->arch.xen.xen_lock);
if (!evtchnfd)
return -ENOENT;
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, **all_evtchnfds;
int i;
int n = 0;
mutex_lock(&kvm->arch.xen.xen_lock);
/*
* Because synchronize_srcu() cannot be called inside the
* critical section, first collect all the evtchnfd objects
* in an array as they are removed from evtchn_ports.
*/
idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i)
n++;
all_evtchnfds = kmalloc_array(n, sizeof(struct evtchnfd *), GFP_KERNEL);
if (!all_evtchnfds) {
mutex_unlock(&kvm->arch.xen.xen_lock);
return -ENOMEM;
}
n = 0;
idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
all_evtchnfds[n++] = evtchnfd;
idr_remove(&kvm->arch.xen.evtchn_ports, evtchnfd->send_port);
}
mutex_unlock(&kvm->arch.xen.xen_lock);
synchronize_srcu(&kvm->srcu);
while (n--) {
evtchnfd = all_evtchnfds[n];
if (!evtchnfd->deliver.port.port)
eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
kfree(evtchnfd);
}
kfree(all_evtchnfds);
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;
struct x86_exception e;
/* Sanity check: this structure is the same for 32-bit and 64-bit */
BUILD_BUG_ON(sizeof(send) != 4);
if (kvm_read_guest_virt(vcpu, param, &send, sizeof(send), &e)) {
*r = -EFAULT;
return true;
}
/*
* evtchnfd is protected by kvm->srcu; the idr lookup instead
* is protected by RCU.
*/
rcu_read_lock();
evtchnfd = idr_find(&vcpu->kvm->arch.xen.evtchn_ports, send.port);
rcu_read_unlock();
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);
}
*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, vcpu->kvm);
kvm_gpc_init(&vcpu->arch.xen.runstate2_cache, vcpu->kvm);
kvm_gpc_init(&vcpu->arch.xen.vcpu_info_cache, vcpu->kvm);
kvm_gpc_init(&vcpu->arch.xen.vcpu_time_info_cache, vcpu->kvm);
}
void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu)
{
if (kvm_xen_timer_enabled(vcpu))
kvm_xen_stop_timer(vcpu);
kvm_gpc_deactivate(&vcpu->arch.xen.runstate_cache);
kvm_gpc_deactivate(&vcpu->arch.xen.runstate2_cache);
kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_info_cache);
kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_time_info_cache);
del_timer_sync(&vcpu->arch.xen.poll_timer);
}
void kvm_xen_update_tsc_info(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *entry;
u32 function;
if (!vcpu->arch.xen.cpuid.base)
return;
function = vcpu->arch.xen.cpuid.base | XEN_CPUID_LEAF(3);
if (function > vcpu->arch.xen.cpuid.limit)
return;
entry = kvm_find_cpuid_entry_index(vcpu, function, 1);
if (entry) {
entry->ecx = vcpu->arch.hv_clock.tsc_to_system_mul;
entry->edx = vcpu->arch.hv_clock.tsc_shift;
}
entry = kvm_find_cpuid_entry_index(vcpu, function, 2);
if (entry)
entry->eax = vcpu->arch.hw_tsc_khz;
}
void kvm_xen_init_vm(struct kvm *kvm)
{
mutex_init(&kvm->arch.xen.xen_lock);
idr_init(&kvm->arch.xen.evtchn_ports);
kvm_gpc_init(&kvm->arch.xen.shinfo_cache, kvm);
}
void kvm_xen_destroy_vm(struct kvm *kvm)
{
struct evtchnfd *evtchnfd;
int i;
kvm_gpc_deactivate(&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);
}