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Diffstat (limited to 'arch/x86/kvm/xen.c')
-rw-r--r--arch/x86/kvm/xen.c313
1 files changed, 218 insertions, 95 deletions
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index b0212ba2d8..f65b35a05d 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -10,7 +10,7 @@
#include "x86.h"
#include "xen.h"
#include "hyperv.h"
-#include "lapic.h"
+#include "irq.h"
#include <linux/eventfd.h>
#include <linux/kvm_host.h>
@@ -24,6 +24,7 @@
#include <xen/interface/sched.h>
#include <asm/xen/cpuid.h>
+#include <asm/pvclock.h>
#include "cpuid.h"
#include "trace.h"
@@ -34,41 +35,32 @@ 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)
+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;
- gpa_t gpa = gfn_to_gpa(gfn);
u32 *wc_sec_hi;
u32 wc_version;
u64 wall_nsec;
int ret = 0;
int idx = srcu_read_lock(&kvm->srcu);
- if (gfn == KVM_XEN_INVALID_GFN) {
- kvm_gpc_deactivate(gpc);
- goto out;
- }
+ read_lock_irq(&gpc->lock);
+ while (!kvm_gpc_check(gpc, PAGE_SIZE)) {
+ read_unlock_irq(&gpc->lock);
- do {
- ret = kvm_gpc_activate(gpc, gpa, PAGE_SIZE);
+ ret = kvm_gpc_refresh(gpc, 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 = kvm_get_wall_clock_epoch(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);
+ /*
+ * 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);
@@ -158,8 +150,93 @@ static enum hrtimer_restart xen_timer_callback(struct hrtimer *timer)
return HRTIMER_NORESTART;
}
-static void kvm_xen_start_timer(struct kvm_vcpu *vcpu, u64 guest_abs, s64 delta_ns)
+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
@@ -171,14 +248,12 @@ static void kvm_xen_start_timer(struct kvm_vcpu *vcpu, u64 guest_abs, s64 delta_
atomic_set(&vcpu->arch.xen.timer_pending, 0);
vcpu->arch.xen.timer_expires = guest_abs;
- if (delta_ns <= 0) {
+ if (delta <= 0)
xen_timer_callback(&vcpu->arch.xen.timer);
- } else {
- ktime_t ktime_now = ktime_get();
+ else
hrtimer_start(&vcpu->arch.xen.timer,
- ktime_add_ns(ktime_now, delta_ns),
+ ktime_add_ns(kernel_now, delta),
HRTIMER_MODE_ABS_HARD);
- }
}
static void kvm_xen_stop_timer(struct kvm_vcpu *vcpu)
@@ -452,14 +527,13 @@ static void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, bool atomic)
smp_wmb();
}
- if (user_len2)
+ 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);
-
- mark_page_dirty_in_slot(v->kvm, gpc1->memslot, gpc1->gpa >> PAGE_SHIFT);
- if (user_len2)
- mark_page_dirty_in_slot(v->kvm, gpc2->memslot, gpc2->gpa >> PAGE_SHIFT);
}
void kvm_xen_update_runstate(struct kvm_vcpu *v, int state)
@@ -496,7 +570,6 @@ void kvm_xen_update_runstate(struct kvm_vcpu *v, int state)
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;
@@ -505,8 +578,7 @@ void kvm_xen_inject_vcpu_vector(struct kvm_vcpu *v)
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));
+ kvm_irq_delivery_to_apic(v->kvm, NULL, &irq, NULL);
}
/*
@@ -565,13 +637,13 @@ void kvm_xen_inject_pending_events(struct kvm_vcpu *v)
: "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);
-
- mark_page_dirty_in_slot(v->kvm, gpc->memslot, gpc->gpa >> PAGE_SHIFT);
}
int __kvm_xen_has_interrupt(struct kvm_vcpu *v)
@@ -635,17 +707,59 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
} 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);
- r = 0;
}
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);
- r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn);
+
+ 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;
@@ -699,13 +813,21 @@ int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
break;
case KVM_XEN_ATTR_TYPE_SHARED_INFO:
- if (kvm->arch.xen.shinfo_cache.active)
+ 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;
@@ -742,20 +864,33 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
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->u.gpa == KVM_XEN_INVALID_GPA) {
- kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_info_cache);
- r = 0;
- break;
+ 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));
}
- r = kvm_gpc_activate(&vcpu->arch.xen.vcpu_info_cache,
- data->u.gpa, sizeof(struct vcpu_info));
if (!r)
kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
@@ -944,9 +1079,7 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
/* 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));
+ kvm_xen_start_timer(vcpu, data->u.timer.expires_ns, false);
r = 0;
break;
@@ -977,13 +1110,21 @@ 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_cache.active)
+ 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;
@@ -1093,9 +1234,24 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data)
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);
- /* Latch long_mode for shared_info pages etc. */
- vcpu->kvm->arch.xen.long_mode = lm;
+ if (r)
+ return r;
/*
* If Xen hypercall intercept is enabled, fill the hypercall
@@ -1396,7 +1552,6 @@ static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd,
{
struct vcpu_set_singleshot_timer oneshot;
struct x86_exception e;
- s64 delta;
if (!kvm_xen_timer_enabled(vcpu))
return false;
@@ -1430,9 +1585,7 @@ static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd,
return true;
}
- /* A delta <= 0 results in an immediate callback, which is what we want */
- delta = oneshot.timeout_abs_ns - get_kvmclock_ns(vcpu->kvm);
- kvm_xen_start_timer(vcpu, oneshot.timeout_abs_ns, delta);
+ kvm_xen_start_timer(vcpu, oneshot.timeout_abs_ns, false);
*r = 0;
return true;
@@ -1455,29 +1608,10 @@ static bool kvm_xen_hcall_set_timer_op(struct kvm_vcpu *vcpu, uint64_t timeout,
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 {
+ if (timeout)
+ kvm_xen_start_timer(vcpu, timeout, true);
+ else
kvm_xen_stop_timer(vcpu);
- }
*r = 0;
return true;
@@ -1621,9 +1755,6 @@ int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe, struct kvm *kvm)
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;
@@ -1731,8 +1862,6 @@ static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm)
mm_borrowed = true;
}
- mutex_lock(&kvm->arch.xen.xen_lock);
-
/*
* It is theoretically possible for the page to be unmapped
* and the MMU notifier to invalidate the shared_info before
@@ -1760,8 +1889,6 @@ static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm)
srcu_read_unlock(&kvm->srcu, idx);
} while(!rc);
- mutex_unlock(&kvm->arch.xen.xen_lock);
-
if (mm_borrowed)
kthread_unuse_mm(kvm->mm);
@@ -2109,14 +2236,10 @@ void kvm_xen_init_vcpu(struct kvm_vcpu *vcpu)
timer_setup(&vcpu->arch.xen.poll_timer, cancel_evtchn_poll, 0);
- kvm_gpc_init(&vcpu->arch.xen.runstate_cache, vcpu->kvm, NULL,
- KVM_HOST_USES_PFN);
- kvm_gpc_init(&vcpu->arch.xen.runstate2_cache, vcpu->kvm, NULL,
- KVM_HOST_USES_PFN);
- kvm_gpc_init(&vcpu->arch.xen.vcpu_info_cache, vcpu->kvm, NULL,
- KVM_HOST_USES_PFN);
- kvm_gpc_init(&vcpu->arch.xen.vcpu_time_info_cache, vcpu->kvm, NULL,
- KVM_HOST_USES_PFN);
+ 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)
@@ -2159,7 +2282,7 @@ 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, NULL, KVM_HOST_USES_PFN);
+ kvm_gpc_init(&kvm->arch.xen.shinfo_cache, kvm);
}
void kvm_xen_destroy_vm(struct kvm *kvm)