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  1. 15 12月, 2018 5 次提交
    • V
      x86/kvm/hyper-v: use stimer config definition from hyperv-tlfs.h · 6a058a1e
      由 Vitaly Kuznetsov 提交于 
      As a preparation to implementing Direct Mode for Hyper-V synthetic
timers switch to using stimer config definition from hyperv-tlfs.h.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      6a058a1e
    • V
      x86/kvm/hyper-v: Introduce KVM_GET_SUPPORTED_HV_CPUID · 2bc39970
      由 Vitaly Kuznetsov 提交于 
      With every new Hyper-V Enlightenment we implement we're forced to add a
KVM_CAP_HYPERV_* capability. While this approach works it is fairly
inconvenient: the majority of the enlightenments we do have corresponding
CPUID feature bit(s) and userspace has to know this anyways to be able to
expose the feature to the guest.

Add KVM_GET_SUPPORTED_HV_CPUID ioctl (backed by KVM_CAP_HYPERV_CPUID, "one
cap to rule them all!") returning all Hyper-V CPUID feature leaves.

Using the existing KVM_GET_SUPPORTED_CPUID doesn't seem to be possible:
Hyper-V CPUID feature leaves intersect with KVM's (e.g. 0x40000000,
0x40000001) and we would probably confuse userspace in case we decide to
return these twice.

KVM_CAP_HYPERV_CPUID's number is interim: we're intended to drop
KVM_CAP_HYPERV_STIMER_DIRECT and use its number instead.
Suggested-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      2bc39970
    • V
      x86/hyper-v: Do some housekeeping in hyperv-tlfs.h · a4987def
      由 Vitaly Kuznetsov 提交于 
      hyperv-tlfs.h is a bit messy: CPUID feature bits are not always sorted,
it's hard to get which CPUID they belong to, some items are duplicated
(e.g. HV_X64_MSR_CRASH_CTL_NOTIFY/HV_CRASH_CTL_CRASH_NOTIFY).

Do some housekeeping work. While on it, replace all (1 << X) with BIT(X)
macro.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: NMichael Kelley <mikelley@microsoft.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      a4987def
    • R
      x86: kvm: hyperv: don't retry message delivery for periodic timers · 7deec5e0
      由 Roman Kagan 提交于 
      The SynIC message delivery protocol allows the message originator to
request, should the message slot be busy, to be notified when it's free.

However, this is unnecessary and even undesirable for messages generated
by SynIC timers in periodic mode: if the period is short enough compared
to the time the guest spends in the timer interrupt handler, so the
timer ticks start piling up, the excessive interactions due to this
notification and retried message delivery only makes the things worse.

[This was observed, in particular, with Windows L2 guests setting
(temporarily) the periodic timer to 2 kHz, and spending hundreds of
microseconds in the timer interrupt handler due to several L2->L1 exits;
under some load in L0 this could exceed 500 us so the timer ticks
started to pile up and the guest livelocked.]

Relieve the situation somewhat by not retrying message delivery for
periodic SynIC timers.  This appears to remain within the "lazy" lost
ticks policy for SynIC timers as implemented in KVM.

Note that it doesn't solve the fundamental problem of livelocking the
guest with a periodic timer whose period is smaller than the time needed
to process a tick, but it makes it a bit less likely to be triggered.
Signed-off-by: NRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      7deec5e0
    • R
      x86: kvm: hyperv: simplify SynIC message delivery · 3a0e7731
      由 Roman Kagan 提交于 
      SynIC message delivery is somewhat overengineered: it pretends to follow
the ordering rules when grabbing the message slot, using atomic
operations and all that, but does it incorrectly and unnecessarily.

The correct order would be to first set .msg_pending, then atomically
replace .message_type if it was zero, and then clear .msg_pending if
the previous step was successful.  But this all is done in vcpu context
so the whole update looks atomic to the guest (it's assumed to only
access the message page from this cpu), and therefore can be done in
whatever order is most convenient (and is also the reason why the
incorrect order didn't trigger any bugs so far).

While at this, also switch to kvm_vcpu_{read,write}_guest_page, and drop
the no longer needed synic_clear_sint_msg_pending.
Signed-off-by: NRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      3a0e7731
  3. 17 10月, 2018 11 次提交
  5. 06 8月, 2018 1 次提交
    • P
      KVM: x86: ensure all MSRs can always be KVM_GET/SET_MSR'd · 44883f01
      由 Paolo Bonzini 提交于 
      Some of the MSRs returned by GET_MSR_INDEX_LIST currently cannot be sent back
to KVM_GET_MSR and/or KVM_SET_MSR; either they can never be sent back, or you
they are only accepted under special conditions.  This makes the API a pain to
use.

To avoid this pain, this patch makes it so that the result of the get-list
ioctl can always be used for host-initiated get and set.  Since we don't have
a separate way to check for read-only MSRs, this means some Hyper-V MSRs are
ignored when written.  Arguably they should not even be in the result of
GET_MSR_INDEX_LIST, but I am leaving there in case userspace is using the
outcome of GET_MSR_INDEX_LIST to derive the support for the corresponding
Hyper-V feature.

Cc: stable@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      44883f01
  7. 26 5月, 2018 5 次提交
  9. 11 5月, 2018 2 次提交
  11. 29 3月, 2018 1 次提交
  13. 24 3月, 2018 1 次提交
  15. 17 3月, 2018 3 次提交
  17. 07 3月, 2018 2 次提交
  19. 08 8月, 2017 2 次提交
  21. 07 8月, 2017 1 次提交
  23. 20 7月, 2017 1 次提交
    • R
      kvm: x86: hyperv: avoid livelock in oneshot SynIC timers · f1ff89ec
      由 Roman Kagan 提交于 
      If the SynIC timer message delivery fails due to SINT message slot being
busy, there's no point to attempt starting the timer again until we're
notified of the slot being released by the guest (via EOM or EOI).

Even worse, when a oneshot timer fails to deliver its message, its
re-arming with an expiration time in the past leads to immediate retry
of the delivery, and so on, without ever letting the guest vcpu to run
and release the slot, which results in a livelock.

To avoid that, only start the timer when there's no timer message
pending delivery.  When there is, meaning the slot is busy, the
processing will be restarted upon notification from the guest that the
slot is released.
Signed-off-by: NRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      f1ff89ec
  25. 14 7月, 2017 1 次提交
    • R
      kvm: x86: hyperv: make VP_INDEX managed by userspace · d3457c87
      由 Roman Kagan 提交于 
      Hyper-V identifies vCPUs by Virtual Processor Index, which can be
queried via HV_X64_MSR_VP_INDEX msr.  It is defined by the spec as a
sequential number which can't exceed the maximum number of vCPUs per VM.
APIC ids can be sparse and thus aren't a valid replacement for VP
indices.

Current KVM uses its internal vcpu index as VP_INDEX.  However, to make
it predictable and persistent across VM migrations, the userspace has to
control the value of VP_INDEX.

This patch achieves that, by storing vp_index explicitly on vcpu, and
allowing HV_X64_MSR_VP_INDEX to be set from the host side.  For
compatibility it's initialized to KVM vcpu index.  Also a few variables
are renamed to make clear distinction betweed this Hyper-V vp_index and
KVM vcpu_id (== APIC id).  Besides, a new capability,
KVM_CAP_HYPERV_VP_INDEX, is added to allow the userspace to skip
attempting msr writes where unsupported, to avoid spamming error logs.
Signed-off-by: NRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      d3457c87
  27. 13 7月, 2017 1 次提交
    • R
      kvm: x86: hyperv: add KVM_CAP_HYPERV_SYNIC2 · efc479e6
      由 Roman Kagan 提交于 
      There is a flaw in the Hyper-V SynIC implementation in KVM: when message
page or event flags page is enabled by setting the corresponding msr,
KVM zeroes it out.  This is problematic because on migration the
corresponding MSRs are loaded on the destination, so the content of
those pages is lost.

This went unnoticed so far because the only user of those pages was
in-KVM hyperv synic timers, which could continue working despite that
zeroing.

Newer QEMU uses those pages for Hyper-V VMBus implementation, and
zeroing them breaks the migration.

Besides, in newer QEMU the content of those pages is fully managed by
QEMU, so zeroing them is undesirable even when writing the MSRs from the
guest side.

To support this new scheme, introduce a new capability,
KVM_CAP_HYPERV_SYNIC2, which, when enabled, makes sure that the synic
pages aren't zeroed out in KVM.
Signed-off-by: NRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      efc479e6
  29. 02 3月, 2017 1 次提交
  31. 01 2月, 2017 1 次提交
    • F
      sched/cputime: Convert task/group cputime to nsecs · 5613fda9
      由 Frederic Weisbecker 提交于 
      Now that most cputime readers use the transition API which return the
task cputime in old style cputime_t, we can safely store the cputime in
nsecs. This will eventually make cputime statistics less opaque and more
granular. Back and forth convertions between cputime_t and nsecs in order
to deal with cputime_t random granularity won't be needed anymore.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1485832191-26889-8-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      5613fda9
  33. 09 1月, 2017 1 次提交