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Diffstat (limited to 'arch/x86/kvm/svm/nested.c')
-rw-r--r--arch/x86/kvm/svm/nested.c70
1 files changed, 53 insertions, 17 deletions
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index b708bdf7eaff..8427a48b8b7a 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -111,7 +111,7 @@ static void nested_svm_uninit_mmu_context(struct kvm_vcpu *vcpu)
static bool nested_vmcb_needs_vls_intercept(struct vcpu_svm *svm)
{
- if (!guest_can_use(&svm->vcpu, X86_FEATURE_V_VMSAVE_VMLOAD))
+ if (!guest_cpu_cap_has(&svm->vcpu, X86_FEATURE_V_VMSAVE_VMLOAD))
return true;
if (!nested_npt_enabled(svm))
@@ -594,7 +594,7 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
vmcb_mark_dirty(vmcb02, VMCB_DR);
}
- if (unlikely(guest_can_use(vcpu, X86_FEATURE_LBRV) &&
+ if (unlikely(guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) &&
(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
/*
* Reserved bits of DEBUGCTL are ignored. Be consistent with
@@ -646,12 +646,17 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
u32 pause_count12;
u32 pause_thresh12;
+ nested_svm_transition_tlb_flush(vcpu);
+
+ /* Enter Guest-Mode */
+ enter_guest_mode(vcpu);
+
/*
* Filled at exit: exit_code, exit_code_hi, exit_info_1, exit_info_2,
* exit_int_info, exit_int_info_err, next_rip, insn_len, insn_bytes.
*/
- if (guest_can_use(vcpu, X86_FEATURE_VGIF) &&
+ if (guest_cpu_cap_has(vcpu, X86_FEATURE_VGIF) &&
(svm->nested.ctl.int_ctl & V_GIF_ENABLE_MASK))
int_ctl_vmcb12_bits |= (V_GIF_MASK | V_GIF_ENABLE_MASK);
else
@@ -673,6 +678,33 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
vmcb02->control.iopm_base_pa = vmcb01->control.iopm_base_pa;
vmcb02->control.msrpm_base_pa = vmcb01->control.msrpm_base_pa;
+ /*
+ * Stash vmcb02's counter if the guest hasn't moved past the guilty
+ * instruction; otherwise, reset the counter to '0'.
+ *
+ * In order to detect if L2 has made forward progress or not, track the
+ * RIP at which a bus lock has occurred on a per-vmcb12 basis. If RIP
+ * is changed, guest has clearly made forward progress, bus_lock_counter
+ * still remained '1', so reset bus_lock_counter to '0'. Eg. In the
+ * scenario, where a buslock happened in L1 before VMRUN, the bus lock
+ * firmly happened on an instruction in the past. Even if vmcb01's
+ * counter is still '1', (because the guilty instruction got patched),
+ * the vCPU has clearly made forward progress and so KVM should reset
+ * vmcb02's counter to '0'.
+ *
+ * If the RIP hasn't changed, stash the bus lock counter at nested VMRUN
+ * to prevent the same guilty instruction from triggering a VM-Exit. Eg.
+ * if userspace rate-limits the vCPU, then it's entirely possible that
+ * L1's tick interrupt is pending by the time userspace re-runs the
+ * vCPU. If KVM unconditionally clears the counter on VMRUN, then when
+ * L1 re-enters L2, the same instruction will trigger a VM-Exit and the
+ * entire cycle start over.
+ */
+ if (vmcb02->save.rip && (svm->nested.ctl.bus_lock_rip == vmcb02->save.rip))
+ vmcb02->control.bus_lock_counter = 1;
+ else
+ vmcb02->control.bus_lock_counter = 0;
+
/* Done at vmrun: asid. */
/* Also overwritten later if necessary. */
@@ -689,7 +721,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
vmcb02->control.tsc_offset = vcpu->arch.tsc_offset;
- if (guest_can_use(vcpu, X86_FEATURE_TSCRATEMSR) &&
+ if (guest_cpu_cap_has(vcpu, X86_FEATURE_TSCRATEMSR) &&
svm->tsc_ratio_msr != kvm_caps.default_tsc_scaling_ratio)
nested_svm_update_tsc_ratio_msr(vcpu);
@@ -710,7 +742,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
* what a nrips=0 CPU would do (L1 is responsible for advancing RIP
* prior to injecting the event).
*/
- if (guest_can_use(vcpu, X86_FEATURE_NRIPS))
+ if (guest_cpu_cap_has(vcpu, X86_FEATURE_NRIPS))
vmcb02->control.next_rip = svm->nested.ctl.next_rip;
else if (boot_cpu_has(X86_FEATURE_NRIPS))
vmcb02->control.next_rip = vmcb12_rip;
@@ -720,7 +752,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
svm->soft_int_injected = true;
svm->soft_int_csbase = vmcb12_csbase;
svm->soft_int_old_rip = vmcb12_rip;
- if (guest_can_use(vcpu, X86_FEATURE_NRIPS))
+ if (guest_cpu_cap_has(vcpu, X86_FEATURE_NRIPS))
svm->soft_int_next_rip = svm->nested.ctl.next_rip;
else
svm->soft_int_next_rip = vmcb12_rip;
@@ -728,18 +760,18 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
vmcb02->control.virt_ext = vmcb01->control.virt_ext &
LBR_CTL_ENABLE_MASK;
- if (guest_can_use(vcpu, X86_FEATURE_LBRV))
+ if (guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV))
vmcb02->control.virt_ext |=
(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK);
if (!nested_vmcb_needs_vls_intercept(svm))
vmcb02->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK;
- if (guest_can_use(vcpu, X86_FEATURE_PAUSEFILTER))
+ if (guest_cpu_cap_has(vcpu, X86_FEATURE_PAUSEFILTER))
pause_count12 = svm->nested.ctl.pause_filter_count;
else
pause_count12 = 0;
- if (guest_can_use(vcpu, X86_FEATURE_PFTHRESHOLD))
+ if (guest_cpu_cap_has(vcpu, X86_FEATURE_PFTHRESHOLD))
pause_thresh12 = svm->nested.ctl.pause_filter_thresh;
else
pause_thresh12 = 0;
@@ -762,11 +794,6 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
}
}
- nested_svm_transition_tlb_flush(vcpu);
-
- /* Enter Guest-Mode */
- enter_guest_mode(vcpu);
-
/*
* Merge guest and host intercepts - must be called with vcpu in
* guest-mode to take effect.
@@ -994,7 +1021,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
kvm_clear_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu);
/* in case we halted in L2 */
- svm->vcpu.arch.mp_state = KVM_MP_STATE_RUNNABLE;
+ kvm_set_mp_state(vcpu, KVM_MP_STATE_RUNNABLE);
/* Give the current vmcb to the guest */
@@ -1026,7 +1053,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
if (vmcb12->control.exit_code != SVM_EXIT_ERR)
nested_save_pending_event_to_vmcb12(svm, vmcb12);
- if (guest_can_use(vcpu, X86_FEATURE_NRIPS))
+ if (guest_cpu_cap_has(vcpu, X86_FEATURE_NRIPS))
vmcb12->control.next_rip = vmcb02->control.next_rip;
vmcb12->control.int_ctl = svm->nested.ctl.int_ctl;
@@ -1039,8 +1066,17 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
}
+ /*
+ * Invalidate bus_lock_rip unless KVM is still waiting for the guest
+ * to make forward progress before re-enabling bus lock detection.
+ */
+ if (!vmcb02->control.bus_lock_counter)
+ svm->nested.ctl.bus_lock_rip = INVALID_GPA;
+
nested_svm_copy_common_state(svm->nested.vmcb02.ptr, svm->vmcb01.ptr);
+ kvm_nested_vmexit_handle_ibrs(vcpu);
+
svm_switch_vmcb(svm, &svm->vmcb01);
/*
@@ -1065,7 +1101,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
if (!nested_exit_on_intr(svm))
kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
- if (unlikely(guest_can_use(vcpu, X86_FEATURE_LBRV) &&
+ if (unlikely(guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) &&
(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
svm_copy_lbrs(vmcb12, vmcb02);
svm_update_lbrv(vcpu);
generated by cgit v1.2.3 (git 2.39.0) at 2025-07-14 07:55:22 +0300