On 2013-02-20 14:01, Jan Kiszka wrote:
> This aligns VMX more with SVM regarding event injection and recovery for
> nested guests. The changes allow to inject interrupts directly from L0
> to L2.
>
> One difference to SVM is that we always transfer the pending event
> injection into the architectural state of the VCPU and then drop it from
> there if it turns out that we left L2 to enter L1.
>
> VMX and SVM are now identical in how they recover event injections from
> unperformed vmlaunch/vmresume: We detect that VM_ENTRY_INTR_INFO_FIELD
> still contains a valid event and, if yes, transfer the content into L1's
> idt_vectoring_info_field.
>
> To avoid that we incorrectly leak an event into the architectural VCPU
> state that L1 wants to inject, we skip cancellation on nested run.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
> ---
>
> Survived moderate testing here and (currently) makes sense to me, but
> please review very carefully. I wouldn't be surprised if I'm still
> missing some subtle corner case.
Forgot to point this out again: It still takes "KVM: nVMX: Fix injection
of PENDING_INTERRUPT and NMI_WINDOW exits to L1" to make L0->L2
injection work. So this patch logically depends on it.
Jan
>
> arch/x86/kvm/vmx.c | 57 +++++++++++++++++++++++----------------------------
> 1 files changed, 26 insertions(+), 31 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index dd3a8a0..7d2fbd2 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -6489,8 +6489,6 @@ static void __vmx_complete_interrupts(struct vcpu_vmx *vmx,
>
> static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
> {
> - if (is_guest_mode(&vmx->vcpu))
> - return;
> __vmx_complete_interrupts(vmx, vmx->idt_vectoring_info,
> VM_EXIT_INSTRUCTION_LEN,
> IDT_VECTORING_ERROR_CODE);
> @@ -6498,7 +6496,7 @@ static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
>
> static void vmx_cancel_injection(struct kvm_vcpu *vcpu)
> {
> - if (is_guest_mode(vcpu))
> + if (to_vmx(vcpu)->nested.nested_run_pending)
> return;
> __vmx_complete_interrupts(to_vmx(vcpu),
> vmcs_read32(VM_ENTRY_INTR_INFO_FIELD),
> @@ -6531,21 +6529,6 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
> struct vcpu_vmx *vmx = to_vmx(vcpu);
> unsigned long debugctlmsr;
>
> - if (is_guest_mode(vcpu) && !vmx->nested.nested_run_pending) {
> - struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
> - if (vmcs12->idt_vectoring_info_field &
> - VECTORING_INFO_VALID_MASK) {
> - vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
> - vmcs12->idt_vectoring_info_field);
> - vmcs_write32(VM_ENTRY_INSTRUCTION_LEN,
> - vmcs12->vm_exit_instruction_len);
> - if (vmcs12->idt_vectoring_info_field &
> - VECTORING_INFO_DELIVER_CODE_MASK)
> - vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE,
> - vmcs12->idt_vectoring_error_code);
> - }
> - }
> -
> /* Record the guest's net vcpu time for enforced NMI injections. */
> if (unlikely(!cpu_has_virtual_nmis() && vmx->soft_vnmi_blocked))
> vmx->entry_time = ktime_get();
> @@ -6704,17 +6687,6 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
>
> vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
>
> - if (is_guest_mode(vcpu)) {
> - struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
> - vmcs12->idt_vectoring_info_field = vmx->idt_vectoring_info;
> - if (vmx->idt_vectoring_info & VECTORING_INFO_VALID_MASK) {
> - vmcs12->idt_vectoring_error_code =
> - vmcs_read32(IDT_VECTORING_ERROR_CODE);
> - vmcs12->vm_exit_instruction_len =
> - vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
> - }
> - }
> -
> vmx->loaded_vmcs->launched = 1;
>
> vmx->exit_reason = vmcs_read32(VM_EXIT_REASON);
> @@ -7403,9 +7375,32 @@ void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
> vmcs12->vm_exit_instruction_len = vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
> vmcs12->vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
>
> - /* clear vm-entry fields which are to be cleared on exit */
> - if (!(vmcs12->vm_exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY))
> + /* drop what we picked up for L0 via vmx_complete_interrupts */
> + vcpu->arch.nmi_injected = false;
> + kvm_clear_exception_queue(vcpu);
> + kvm_clear_interrupt_queue(vcpu);
> +
> + if (!(vmcs12->vm_exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY) &&
> + vmcs12->vm_entry_intr_info_field & INTR_INFO_VALID_MASK) {
> + /*
> + * Preserve the event that was supposed to be injected
> + * by emulating it would have been returned in
> + * IDT_VECTORING_INFO_FIELD.
> + */
> + if (vmcs_read32(VM_ENTRY_INTR_INFO_FIELD) &
> + INTR_INFO_VALID_MASK) {
> + vmcs12->idt_vectoring_info_field =
> + vmcs12->vm_entry_intr_info_field;
> + vmcs12->idt_vectoring_error_code =
> + vmcs12->vm_entry_exception_error_code;
> + vmcs12->vm_exit_instruction_len =
> + vmcs12->vm_entry_instruction_len;
> + vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, 0);
> + }
> +
> + /* clear vm-entry fields which are to be cleared on exit */
> vmcs12->vm_entry_intr_info_field &= ~INTR_INFO_VALID_MASK;
> + }
> }
>
> /*
>
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux
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