diff options
author | Peter Shier <pshier@google.com> | 2020-05-26 14:51:06 -0700 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-06-01 04:26:10 -0400 |
commit | 850448f35aaf45215276468d63c91ab1e230cf06 (patch) | |
tree | a47f2d1d880e70bb4fe7cf989b9dcc32aa699b42 /arch/x86/kvm | |
parent | f7d31e65368aeef973fab788aa22c4f1d5a6af66 (diff) |
KVM: nVMX: Fix VMX preemption timer migration
Add new field to hold preemption timer expiration deadline
appended to struct kvm_vmx_nested_state_hdr. This is to prevent
the first VM-Enter after migration from incorrectly restarting the timer
with the full timer value instead of partially decayed timer value.
KVM_SET_NESTED_STATE restarts timer using migrated state regardless
of whether L1 sets VM_EXIT_SAVE_VMX_PREEMPTION_TIMER.
Fixes: cf8b84f48a593 ("kvm: nVMX: Prepare for checkpointing L2 state")
Signed-off-by: Peter Shier <pshier@google.com>
Signed-off-by: Makarand Sonare <makarandsonare@google.com>
Message-Id: <20200526215107.205814-2-makarandsonare@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r-- | arch/x86/kvm/vmx/nested.c | 55 | ||||
-rw-r--r-- | arch/x86/kvm/vmx/vmx.h | 2 |
2 files changed, 49 insertions, 8 deletions
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 119a2f7395d6..da87bb8670bb 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -2087,9 +2087,29 @@ static enum hrtimer_restart vmx_preemption_timer_fn(struct hrtimer *timer) return HRTIMER_NORESTART; } -static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu) +static u64 vmx_calc_preemption_timer_value(struct kvm_vcpu *vcpu) +{ + struct vcpu_vmx *vmx = to_vmx(vcpu); + struct vmcs12 *vmcs12 = get_vmcs12(vcpu); + u64 timer_value = 0; + + u64 l1_scaled_tsc = kvm_read_l1_tsc(vcpu, rdtsc()) >> + VMX_MISC_EMULATED_PREEMPTION_TIMER_RATE; + + if (!vmx->nested.has_preemption_timer_deadline) { + timer_value = vmcs12->vmx_preemption_timer_value; + vmx->nested.preemption_timer_deadline = timer_value + + l1_scaled_tsc; + vmx->nested.has_preemption_timer_deadline = true; + } else if (l1_scaled_tsc < vmx->nested.preemption_timer_deadline) + timer_value = vmx->nested.preemption_timer_deadline - + l1_scaled_tsc; + return timer_value; +} + +static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu, + u64 preemption_timeout) { - u64 preemption_timeout = get_vmcs12(vcpu)->vmx_preemption_timer_value; struct vcpu_vmx *vmx = to_vmx(vcpu); /* @@ -3348,8 +3368,10 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu, * the timer. */ vmx->nested.preemption_timer_expired = false; - if (nested_cpu_has_preemption_timer(vmcs12)) - vmx_start_preemption_timer(vcpu); + if (nested_cpu_has_preemption_timer(vmcs12)) { + u64 timer_value = vmx_calc_preemption_timer_value(vcpu); + vmx_start_preemption_timer(vcpu, timer_value); + } /* * Note no nested_vmx_succeed or nested_vmx_fail here. At this point @@ -3457,6 +3479,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) * the nested entry. */ vmx->nested.nested_run_pending = 1; + vmx->nested.has_preemption_timer_deadline = false; status = nested_vmx_enter_non_root_mode(vcpu, true); if (unlikely(status != NVMX_VMENTRY_SUCCESS)) goto vmentry_failed; @@ -3957,9 +3980,10 @@ static void sync_vmcs02_to_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) vmcs12->guest_activity_state = GUEST_ACTIVITY_ACTIVE; if (nested_cpu_has_preemption_timer(vmcs12) && - vmcs12->vm_exit_controls & VM_EXIT_SAVE_VMX_PREEMPTION_TIMER) - vmcs12->vmx_preemption_timer_value = - vmx_get_preemption_timer_value(vcpu); + vmcs12->vm_exit_controls & VM_EXIT_SAVE_VMX_PREEMPTION_TIMER && + !vmx->nested.nested_run_pending) + vmcs12->vmx_preemption_timer_value = + vmx_get_preemption_timer_value(vcpu); /* * In some cases (usually, nested EPT), L2 is allowed to change its @@ -5891,8 +5915,10 @@ static int vmx_get_nested_state(struct kvm_vcpu *vcpu, .flags = 0, .format = KVM_STATE_NESTED_FORMAT_VMX, .size = sizeof(kvm_state), + .hdr.vmx.flags = 0, .hdr.vmx.vmxon_pa = -1ull, .hdr.vmx.vmcs12_pa = -1ull, + .hdr.vmx.preemption_timer_deadline = 0, }; struct kvm_vmx_nested_state_data __user *user_vmx_nested_state = &user_kvm_nested_state->data.vmx[0]; @@ -5934,6 +5960,14 @@ static int vmx_get_nested_state(struct kvm_vcpu *vcpu, if (vmx->nested.mtf_pending) kvm_state.flags |= KVM_STATE_NESTED_MTF_PENDING; + + if (nested_cpu_has_preemption_timer(vmcs12) && + vmx->nested.has_preemption_timer_deadline) { + kvm_state.hdr.vmx.flags |= + KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE; + kvm_state.hdr.vmx.preemption_timer_deadline = + vmx->nested.preemption_timer_deadline; + } } } @@ -5979,7 +6013,6 @@ static int vmx_get_nested_state(struct kvm_vcpu *vcpu, get_shadow_vmcs12(vcpu), VMCS12_SIZE)) return -EFAULT; } - out: return kvm_state.size; } @@ -6141,6 +6174,12 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu, goto error_guest_mode; } + if (kvm_state->hdr.vmx.flags & KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE) { + vmx->nested.has_preemption_timer_deadline = true; + vmx->nested.preemption_timer_deadline = + kvm_state->hdr.vmx.preemption_timer_deadline; + } + if (nested_vmx_check_controls(vcpu, vmcs12) || nested_vmx_check_host_state(vcpu, vmcs12) || nested_vmx_check_guest_state(vcpu, vmcs12, &ignored)) diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index 298ddef79d00..672c28f17e49 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -169,6 +169,8 @@ struct nested_vmx { u16 posted_intr_nv; struct hrtimer preemption_timer; + u64 preemption_timer_deadline; + bool has_preemption_timer_deadline; bool preemption_timer_expired; /* to migrate it to L2 if VM_ENTRY_LOAD_DEBUG_CONTROLS is off */ |