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  1. 09 6月, 2021 1 次提交
  3. 27 5月, 2021 2 次提交
  5. 03 5月, 2021 1 次提交
  7. 26 4月, 2021 1 次提交
    • V
      KVM: x86: Properly handle APF vs disabled LAPIC situation · 2f15d027
      由 Vitaly Kuznetsov 提交于 
      Async PF 'page ready' event may happen when LAPIC is (temporary) disabled.
In particular, Sebastien reports that when Linux kernel is directly booted
by Cloud Hypervisor, LAPIC is 'software disabled' when APF mechanism is
initialized. On initialization KVM tries to inject 'wakeup all' event and
puts the corresponding token to the slot. It is, however, failing to inject
an interrupt (kvm_apic_set_irq() -> __apic_accept_irq() -> !apic_enabled())
so the guest never gets notified and the whole APF mechanism gets stuck.
The same issue is likely to happen if the guest temporary disables LAPIC
and a previously unavailable page becomes available.

Do two things to resolve the issue:
- Avoid dequeuing 'page ready' events from APF queue when LAPIC is
  disabled.
- Trigger an attempt to deliver pending 'page ready' events when LAPIC
  becomes enabled (SPIV or MSR_IA32_APICBASE).
Reported-by: NSebastien Boeuf <sebastien.boeuf@intel.com>
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210422092948.568327-1-vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      2f15d027
  9. 15 3月, 2021 1 次提交
    • S
      KVM: x86: Handle triple fault in L2 without killing L1 · cb6a32c2
      由 Sean Christopherson 提交于 
      Synthesize a nested VM-Exit if L2 triggers an emulated triple fault
instead of exiting to userspace, which likely will kill L1.  Any flow
that does KVM_REQ_TRIPLE_FAULT is suspect, but the most common scenario
for L2 killing L1 is if L0 (KVM) intercepts a contributory exception that
is _not_intercepted by L1.  E.g. if KVM is intercepting #GPs for the
VMware backdoor, a #GP that occurs in L2 while vectoring an injected #DF
will cause KVM to emulate triple fault.

Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: NSean Christopherson <seanjc@google.com>
Message-Id: <20210302174515.2812275-2-seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      cb6a32c2
  11. 13 3月, 2021 1 次提交
  13. 05 3月, 2021 1 次提交
  15. 09 2月, 2021 2 次提交
    • V
      KVM: x86: hyper-v: Prepare to meet unallocated Hyper-V context · f2bc14b6
      由 Vitaly Kuznetsov 提交于 
      Currently, Hyper-V context is part of 'struct kvm_vcpu_arch' and is always
available. As a preparation to allocating it dynamically, check that it is
not NULL at call sites which can normally proceed without it i.e. the
behavior is identical to the situation when Hyper-V emulation is not being
used by the guest.

When Hyper-V context for a particular vCPU is not allocated, we may still
need to get 'vp_index' from there. E.g. in a hypothetical situation when
Hyper-V emulation was enabled on one CPU and wasn't on another, Hyper-V
style send-IPI hypercall may still be used. Luckily, vp_index is always
initialized to kvm_vcpu_get_idx() and can only be changed when Hyper-V
context is present. Introduce kvm_hv_get_vpindex() helper for
simplification.

No functional change intended.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210126134816.1880136-12-vkuznets@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      f2bc14b6
    • V
      KVM: x86: hyper-v: Rename vcpu_to_synic()/synic_to_vcpu() · e0121fa2
      由 Vitaly Kuznetsov 提交于 
      vcpu_to_synic()'s argument is almost always 'vcpu' so there's no need to
have an additional prefix. Also, as this is used outside of hyper-v
emulation code, add '_hv_' part to make it clear what this s. This makes
the naming more consistent with to_hv_vcpu().

Rename synic_to_vcpu() to hv_synic_to_vcpu() for consistency.

No functional change intended.
Suggested-by: NSean Christopherson <seanjc@google.com>
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210126134816.1880136-6-vkuznets@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      e0121fa2
  17. 04 2月, 2021 2 次提交
    • J
      KVM: x86: use static calls to reduce kvm_x86_ops overhead · b3646477
      由 Jason Baron 提交于 
      Convert kvm_x86_ops to use static calls. Note that all kvm_x86_ops are
covered here except for 'pmu_ops and 'nested ops'.

Here are some numbers running cpuid in a loop of 1 million calls averaged
over 5 runs, measured in the vm (lower is better).

Intel Xeon 3000MHz:

           |default    |mitigations=off
-------------------------------------
vanilla    |.671s      |.486s
static call|.573s(-15%)|.458s(-6%)

AMD EPYC 2500MHz:

           |default    |mitigations=off
-------------------------------------
vanilla    |.710s      |.609s
static call|.664s(-6%) |.609s(0%)

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: NJason Baron <jbaron@akamai.com>
Message-Id: <e057bf1b8a7ad15652df6eeba3f907ae758d3399.1610680941.git.jbaron@akamai.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      b3646477
    • C
      KVM: Stop using deprecated jump label APIs · 6e4e3b4d
      由 Cun Li 提交于 
      The use of 'struct static_key' and 'static_key_false' is
deprecated. Use the new API.
Signed-off-by: NCun Li <cun.jia.li@gmail.com>
Message-Id: <20210111152435.50275-1-cun.jia.li@gmail.com>
[Make it compile.  While at it, rename kvm_no_apic_vcpu to
 kvm_has_noapic_vcpu; the former reads too much like "true if
 no vCPU has an APIC". - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      6e4e3b4d
  19. 08 1月, 2021 2 次提交
    • T
      KVM: SVM: Add support for booting APs in an SEV-ES guest · 647daca2
      由 Tom Lendacky 提交于 
      Typically under KVM, an AP is booted using the INIT-SIPI-SIPI sequence,
where the guest vCPU register state is updated and then the vCPU is VMRUN
to begin execution of the AP. For an SEV-ES guest, this won't work because
the guest register state is encrypted.

Following the GHCB specification, the hypervisor must not alter the guest
register state, so KVM must track an AP/vCPU boot. Should the guest want
to park the AP, it must use the AP Reset Hold exit event in place of, for
example, a HLT loop.

First AP boot (first INIT-SIPI-SIPI sequence):
  Execute the AP (vCPU) as it was initialized and measured by the SEV-ES
  support. It is up to the guest to transfer control of the AP to the
  proper location.

Subsequent AP boot:
  KVM will expect to receive an AP Reset Hold exit event indicating that
  the vCPU is being parked and will require an INIT-SIPI-SIPI sequence to
  awaken it. When the AP Reset Hold exit event is received, KVM will place
  the vCPU into a simulated HLT mode. Upon receiving the INIT-SIPI-SIPI
  sequence, KVM will make the vCPU runnable. It is again up to the guest
  to then transfer control of the AP to the proper location.

  To differentiate between an actual HLT and an AP Reset Hold, a new MP
  state is introduced, KVM_MP_STATE_AP_RESET_HOLD, which the vCPU is
  placed in upon receiving the AP Reset Hold exit event. Additionally, to
  communicate the AP Reset Hold exit event up to userspace (if needed), a
  new exit reason is introduced, KVM_EXIT_AP_RESET_HOLD.

A new x86 ops function is introduced, vcpu_deliver_sipi_vector, in order
to accomplish AP booting. For VMX, vcpu_deliver_sipi_vector is set to the
original SIPI delivery function, kvm_vcpu_deliver_sipi_vector(). SVM adds
a new function that, for non SEV-ES guests, invokes the original SIPI
delivery function, kvm_vcpu_deliver_sipi_vector(), but for SEV-ES guests,
implements the logic above.
Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com>
Message-Id: <e8fbebe8eb161ceaabdad7c01a5859a78b424d5e.1609791600.git.thomas.lendacky@amd.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      647daca2
    • S
      KVM: x86: change in pv_eoi_get_pending() to make code more readable · de7860c8
      由 Stephen Zhang 提交于 
      Signed-off-by: NStephen Zhang <stephenzhangzsd@gmail.com>
Message-Id: <1608277897-1932-1-git-send-email-stephenzhangzsd@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      de7860c8
  21. 10 12月, 2020 1 次提交
  23. 27 11月, 2020 1 次提交
  25. 15 11月, 2020 1 次提交
    • P
      KVM: x86: fix apic_accept_events vs check_nested_events · 1c96dcce
      由 Paolo Bonzini 提交于 
      vmx_apic_init_signal_blocked is buggy in that it returns true
even in VMX non-root mode.  In non-root mode, however, INITs
are not latched, they just cause a vmexit.  Previously,
KVM was waiting for them to be processed when kvm_apic_accept_events
and in the meanwhile it ate the SIPIs that the processor received.

However, in order to implement the wait-for-SIPI activity state,
KVM will have to process KVM_APIC_SIPI in vmx_check_nested_events,
and it will not be possible anymore to disregard SIPIs in non-root
mode as the code is currently doing.

By calling kvm_x86_ops.nested_ops->check_events, we can force a vmexit
(with the side-effect of latching INITs) before incorrectly injecting
an INIT or SIPI in a guest, and therefore vmx_apic_init_signal_blocked
can do the right thing.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      1c96dcce
  27. 28 9月, 2020 6 次提交
  29. 24 8月, 2020 1 次提交
  31. 31 7月, 2020 2 次提交
  33. 27 7月, 2020 1 次提交
  35. 09 7月, 2020 2 次提交
  37. 23 6月, 2020 2 次提交
    • P
      KVM: LAPIC: ensure APIC map is up to date on concurrent update requests · 44d52717
      由 Paolo Bonzini 提交于 
      The following race can cause lost map update events:

         cpu1                            cpu2

                                apic_map_dirty = true
  ------------------------------------------------------------
                                kvm_recalculate_apic_map:
                                     pass check
                                         mutex_lock(&kvm->arch.apic_map_lock);
                                         if (!kvm->arch.apic_map_dirty)
                                     and in process of updating map
  -------------------------------------------------------------
    other calls to
       apic_map_dirty = true         might be too late for affected cpu
  -------------------------------------------------------------
                                     apic_map_dirty = false
  -------------------------------------------------------------
    kvm_recalculate_apic_map:
    bail out on
      if (!kvm->arch.apic_map_dirty)

To fix it, record the beginning of an update of the APIC map in
apic_map_dirty.  If another APIC map change switches apic_map_dirty
back to DIRTY during the update, kvm_recalculate_apic_map should not
make it CLEAN, and the other caller will go through the slow path.
Reported-by: NIgor Mammedov <imammedo@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      44d52717
    • I
      kvm: lapic: fix broken vcpu hotplug · af28dfac
      由 Igor Mammedov 提交于 
      Guest fails to online hotplugged CPU with error
  smpboot: do_boot_cpu failed(-1) to wakeup CPU#4

It's caused by the fact that kvm_apic_set_state(), which used to call
recalculate_apic_map() unconditionally and pulled hotplugged CPU into
apic map, is updating map conditionally on state changes.  In this case
the APIC map is not considered dirty and the is not updated.

Fix the issue by forcing unconditional update from kvm_apic_set_state(),
like it used to be.

Fixes: 4abaffce ("KVM: LAPIC: Recalculate apic map in batch")
Cc: stable@vger.kernel.org
Signed-off-by: NIgor Mammedov <imammedo@redhat.com>
Message-Id: <20200622160830.426022-1-imammedo@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      af28dfac
  39. 28 5月, 2020 1 次提交
  41. 16 5月, 2020 2 次提交
  43. 14 5月, 2020 1 次提交
    • D
      kvm: Replace vcpu->swait with rcuwait · da4ad88c
      由 Davidlohr Bueso 提交于 
      The use of any sort of waitqueue (simple or regular) for
wait/waking vcpus has always been an overkill and semantically
wrong. Because this is per-vcpu (which is blocked) there is
only ever a single waiting vcpu, thus no need for any sort of
queue.

As such, make use of the rcuwait primitive, with the following
considerations:

  - rcuwait already provides the proper barriers that serialize
  concurrent waiter and waker.

  - Task wakeup is done in rcu read critical region, with a
  stable task pointer.

  - Because there is no concurrency among waiters, we need
  not worry about rcuwait_wait_event() calls corrupting
  the wait->task. As a consequence, this saves the locking
  done in swait when modifying the queue. This also applies
  to per-vcore wait for powerpc kvm-hv.

The x86 tscdeadline_latency test mentioned in 8577370f
("KVM: Use simple waitqueue for vcpu->wq") shows that, on avg,
latency is reduced by around 15-20% with this change.

Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: kvmarm@lists.cs.columbia.edu
Cc: linux-mips@vger.kernel.org
Reviewed-by: NMarc Zyngier <maz@kernel.org>
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Message-Id: <20200424054837.5138-6-dave@stgolabs.net>
[Avoid extra logic changes. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      da4ad88c
  45. 16 4月, 2020 1 次提交
    • P
      KVM: x86: Return updated timer current count register from KVM_GET_LAPIC · 24647e0a
      由 Peter Shier 提交于 
      kvm_vcpu_ioctl_get_lapic (implements KVM_GET_LAPIC ioctl) does a bulk copy
of the LAPIC registers but must take into account that the one-shot and
periodic timer current count register is computed upon reads and is not
present in register state. When restoring LAPIC state (e.g. after
migration), restart timers from their their current count values at time of
save.

Note: When a one-shot timer expires, the code in arch/x86/kvm/lapic.c does
not zero the value of the LAPIC initial count register (emulating HW
behavior). If no other timer is run and pending prior to a subsequent
KVM_GET_LAPIC call, the returned register set will include the expired
one-shot initial count. On a subsequent KVM_SET_LAPIC call the code will
see a non-zero initial count and start a new one-shot timer using the
expired timer's count. This is a prior existing bug and will be addressed
in a separate patch. Thanks to jmattson@google.com for this find.
Signed-off-by: NPeter Shier <pshier@google.com>
Reviewed-by: NJim Mattson <jmattson@google.com>
Reviewed-by: NWanpeng Li <wanpengli@tencent.com>
Message-Id: <20181010225653.238911-1-pshier@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      24647e0a
  47. 07 4月, 2020 1 次提交
  49. 31 3月, 2020 1 次提交
  51. 26 3月, 2020 1 次提交
  53. 24 3月, 2020 1 次提交