diff options
| author | Sean Christopherson <seanjc@google.com> | 2021-12-08 01:52:17 +0000 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-01-19 12:14:39 -0500 |
| commit | 98c25ead5eda5e9d41abe57839ad3e8caf19500c (patch) | |
| tree | 0c593e670307c915cfe9b9bea26983300f96ed26 /arch/x86 | |
| parent | 12a8eee5686ef3ea7d8db90cd664f11e4a39e349 (diff) | |
| download | linux-98c25ead5eda5e9d41abe57839ad3e8caf19500c.tar.bz2 | |
KVM: VMX: Move preemption timer <=> hrtimer dance to common x86
Handle the switch to/from the hypervisor/software timer when a vCPU is
blocking in common x86 instead of in VMX. Even though VMX is the only
user of a hypervisor timer, the logic and all functions involved are
generic x86 (unless future CPUs do something completely different and
implement a hypervisor timer that runs regardless of mode).
Handling the switch in common x86 will allow for the elimination of the
pre/post_blocks hooks, and also lets KVM switch back to the hypervisor
timer if and only if it was in use (without additional params). Add a
comment explaining why the switch cannot be deferred to kvm_sched_out()
or kvm_vcpu_block().
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20211208015236.1616697-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 6 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 21 |
2 files changed, 22 insertions, 5 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 1840898bb184..70be166833ac 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -7568,16 +7568,12 @@ void vmx_update_cpu_dirty_logging(struct kvm_vcpu *vcpu) static int vmx_pre_block(struct kvm_vcpu *vcpu) { - if (kvm_lapic_hv_timer_in_use(vcpu)) - kvm_lapic_switch_to_sw_timer(vcpu); - return 0; } static void vmx_post_block(struct kvm_vcpu *vcpu) { - if (kvm_x86_ops.set_hv_timer) - kvm_lapic_switch_to_hv_timer(vcpu); + } static void vmx_setup_mce(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 49ff85e966d7..943706a09e6e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10146,8 +10146,21 @@ out: static inline int vcpu_block(struct kvm *kvm, struct kvm_vcpu *vcpu) { + bool hv_timer; + if (!kvm_arch_vcpu_runnable(vcpu) && (!kvm_x86_ops.pre_block || static_call(kvm_x86_pre_block)(vcpu) == 0)) { + /* + * Switch to the software timer before halt-polling/blocking as + * the guest's timer may be a break event for the vCPU, and the + * hypervisor timer runs only when the CPU is in guest mode. + * Switch before halt-polling so that KVM recognizes an expired + * timer before blocking. + */ + hv_timer = kvm_lapic_hv_timer_in_use(vcpu); + if (hv_timer) + kvm_lapic_switch_to_sw_timer(vcpu); + srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED) kvm_vcpu_halt(vcpu); @@ -10155,6 +10168,9 @@ static inline int vcpu_block(struct kvm *kvm, struct kvm_vcpu *vcpu) kvm_vcpu_block(vcpu); vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); + if (hv_timer) + kvm_lapic_switch_to_hv_timer(vcpu); + if (kvm_x86_ops.post_block) static_call(kvm_x86_post_block)(vcpu); @@ -10349,6 +10365,11 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) r = -EINTR; goto out; } + /* + * It should be impossible for the hypervisor timer to be in + * use before KVM has ever run the vCPU. + */ + WARN_ON_ONCE(kvm_lapic_hv_timer_in_use(vcpu)); kvm_vcpu_block(vcpu); if (kvm_apic_accept_events(vcpu) < 0) { r = 0; |