69 lines
2.6 KiB
Diff
69 lines
2.6 KiB
Diff
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# Commit 244582a01dcb49fa30083725964a066937cc94f2
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# Date 2015-09-11 16:24:56 +0200
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# Author Kouya Shimura <kouya@jp.fujitsu.com>
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# Committer Jan Beulich <jbeulich@suse.com>
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x86/hvm: fix saved pmtimer and hpet values
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The ACPI PM timer is sometimes broken on live migration.
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Since vcpu->arch.hvm_vcpu.guest_time is always zero in other than
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"delay for missed ticks mode". Even in "delay for missed ticks mode",
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vcpu's guest_time field is not valid (i.e. zero) when
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the state of vcpu is "blocked". (see pt_save_timer function)
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The original author (Tim Deegan) of pmtimer_save() must have intended
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that it saves the last scheduled time of the vcpu. Unfortunately it was
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already implied this bug. FYI, there is no other timer mode than
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"delay for missed ticks mode" then.
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For consistency with HPET, pmtimer_save() should refer hvm_get_guest_time()
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to update the counter as well as hpet_save() does.
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Without this patch, the clock of windows server 2012R2 without HPET
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might leap forward several minutes on live migration.
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Signed-off-by: Kouya Shimura <kouya@jp.fujitsu.com>
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Retain use of ->arch.hvm_vcpu.guest_time when non-zero. Do the inverse
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adjustment for vHPET.
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Signed-off-by: Jan Beulich <jbeulich@suse.com>
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Reviewed-by: Tim Deegan <tim@xen.org>
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Reviewed-by: Kouya Shimura <kouya@jp.fujitsu.com>
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--- a/xen/arch/x86/hvm/hpet.c
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+++ b/xen/arch/x86/hvm/hpet.c
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@@ -506,11 +506,13 @@ const struct hvm_mmio_handler hpet_mmio_
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static int hpet_save(struct domain *d, hvm_domain_context_t *h)
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{
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HPETState *hp = domain_vhpet(d);
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+ struct vcpu *v = pt_global_vcpu_target(d);
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int rc;
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uint64_t guest_time;
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write_lock(&hp->lock);
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- guest_time = guest_time_hpet(hp);
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+ guest_time = (v->arch.hvm_vcpu.guest_time ?: hvm_get_guest_time(v)) /
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+ STIME_PER_HPET_TICK;
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/* Write the proper value into the main counter */
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if ( hpet_enabled(hp) )
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--- a/xen/arch/x86/hvm/pmtimer.c
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+++ b/xen/arch/x86/hvm/pmtimer.c
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@@ -250,10 +250,12 @@ static int pmtimer_save(struct domain *d
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spin_lock(&s->lock);
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- /* Update the counter to the guest's current time. We always save
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- * with the domain paused, so the saved time should be after the
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- * last_gtime, but just in case, make sure we only go forwards */
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- x = ((s->vcpu->arch.hvm_vcpu.guest_time - s->last_gtime) * s->scale) >> 32;
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+ /*
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+ * Update the counter to the guest's current time. Make sure it only
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+ * goes forwards.
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+ */
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+ x = (((s->vcpu->arch.hvm_vcpu.guest_time ?: hvm_get_guest_time(s->vcpu)) -
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+ s->last_gtime) * s->scale) >> 32;
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if ( x < 1UL<<31 )
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s->pm.tmr_val += x;
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if ( (s->pm.tmr_val & TMR_VAL_MSB) != msb )
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