From 66c78ae40cd0a7258d01ef433ede74e33e4adbbe Mon Sep 17 00:00:00 2001 From: Nadav Har'El Date: Wed, 25 May 2011 23:14:07 +0300 Subject: [PATCH] KVM: nVMX: Correct handling of idt vectoring info This patch adds correct handling of IDT_VECTORING_INFO_FIELD for the nested case. When a guest exits while delivering an interrupt or exception, we get this information in IDT_VECTORING_INFO_FIELD in the VMCS. When L2 exits to L1, there's nothing we need to do, because L1 will see this field in vmcs12, and handle it itself. However, when L2 exits and L0 handles the exit itself and plans to return to L2, L0 must inject this event to L2. In the normal non-nested case, the idt_vectoring_info case is discovered after the exit, and the decision to inject (though not the injection itself) is made at that point. However, in the nested case a decision of whether to return to L2 or L1 also happens during the injection phase (see the previous patches), so in the nested case we can only decide what to do about the idt_vectoring_info right after the injection, i.e., in the beginning of vmx_vcpu_run, which is the first time we know for sure if we're staying in L2. Therefore, when we exit L2 (is_guest_mode(vcpu)), we disable the regular vmx_complete_interrupts() code which queues the idt_vectoring_info for injection on next entry - because such injection would not be appropriate if we will decide to exit to L1. Rather, we just save the idt_vectoring_info and related fields in vmcs12 (which is a convenient place to save these fields). On the next entry in vmx_vcpu_run (*after* the injection phase, potentially exiting to L1 to inject an event requested by user space), if we find ourselves in L1 we don't need to do anything with those values we saved (as explained above). But if we find that we're in L2, or rather *still* at L2 (it's not nested_run_pending, meaning that this is the first round of L2 running after L1 having just launched it), we need to inject the event saved in those fields - by writing the appropriate VMCS fields. Signed-off-by: Nadav Har'El Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/vmx.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 9604af7675e8..1e6bd69ae433 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -5797,6 +5797,8 @@ 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); @@ -5804,6 +5806,8 @@ static void vmx_complete_interrupts(struct vcpu_vmx *vmx) static void vmx_cancel_injection(struct kvm_vcpu *vcpu) { + if (is_guest_mode(vcpu)) + return; __vmx_complete_interrupts(to_vmx(vcpu), vmcs_read32(VM_ENTRY_INTR_INFO_FIELD), VM_ENTRY_INSTRUCTION_LEN, @@ -5824,6 +5828,21 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); + 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(); @@ -5956,6 +5975,17 @@ 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); + } + } + asm("mov %0, %%ds; mov %0, %%es" : : "r"(__USER_DS)); vmx->loaded_vmcs->launched = 1;