diff options
| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2020-04-22 19:25:39 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-05-13 12:14:27 -0400 |
| commit | d2060bd42e4482b15c35f961a294ee57f369027d (patch) | |
| tree | 860fb89ee17052748e003aa336eab08b74826c57 /arch/x86/kvm/x86.c | |
| parent | 6ce347af1499deff5890a52aedacd451330af706 (diff) | |
KVM: nVMX: Open a window for pending nested VMX preemption timer
Add a kvm_x86_ops hook to detect a nested pending "hypervisor timer" and
use it to effectively open a window for servicing the expired timer.
Like pending SMIs on VMX, opening a window simply means requesting an
immediate exit.
This fixes a bug where an expired VMX preemption timer (for L2) will be
delayed and/or lost if a pending exception is injected into L2. The
pending exception is rightly prioritized by vmx_check_nested_events()
and injected into L2, with the preemption timer left pending. Because
no window opened, L2 is free to run uninterrupted.
Fixes: f4124500c2c13 ("KVM: nVMX: Fully emulate preemption timer")
Reported-by: Jim Mattson <jmattson@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Peter Shier <pshier@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-3-sean.j.christopherson@intel.com>
[Check it in kvm_vcpu_has_events too, to ensure that the preemption
timer is serviced promptly even if the vCPU is halted and L1 is not
intercepting HLT. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 542a00008caa..e874182d113c 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8355,6 +8355,10 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) kvm_x86_ops.enable_nmi_window(vcpu); if (kvm_cpu_has_injectable_intr(vcpu) || req_int_win) kvm_x86_ops.enable_irq_window(vcpu); + if (is_guest_mode(vcpu) && + kvm_x86_ops.nested_ops->hv_timer_pending && + kvm_x86_ops.nested_ops->hv_timer_pending(vcpu)) + req_immediate_exit = true; WARN_ON(vcpu->arch.exception.pending); } @@ -10211,6 +10215,11 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu) if (kvm_hv_has_stimer_pending(vcpu)) return true; + if (is_guest_mode(vcpu) && + kvm_x86_ops.nested_ops->hv_timer_pending && + kvm_x86_ops.nested_ops->hv_timer_pending(vcpu)) + return true; + return false; } |