diff options
| -rw-r--r-- | arch/x86/kvm/x86.c | 35 |
1 files changed, 28 insertions, 7 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0050509a7de2..31aaff9db083 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12175,6 +12175,25 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index, struct x86_emulate_ctxt *ctxt = vcpu->arch.emulate_ctxt; int ret; + if (kvm_is_cr4_bit_set(vcpu, X86_CR4_CET)) { + u64 u_cet, s_cet; + + /* + * Check both User and Supervisor on task switches as inter- + * privilege level task switches are impacted by CET at both + * the current privilege level and the new privilege level, and + * that information is not known at this time. The expectation + * is that the guest won't require emulation of task switches + * while using IBT or Shadow Stacks. + */ + if (__kvm_emulate_msr_read(vcpu, MSR_IA32_U_CET, &u_cet) || + __kvm_emulate_msr_read(vcpu, MSR_IA32_S_CET, &s_cet)) + goto unhandled_task_switch; + + if ((u_cet | s_cet) & (CET_ENDBR_EN | CET_SHSTK_EN)) + goto unhandled_task_switch; + } + init_emulate_ctxt(vcpu); ret = emulator_task_switch(ctxt, tss_selector, idt_index, reason, @@ -12184,17 +12203,19 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index, * Report an error userspace if MMIO is needed, as KVM doesn't support * MMIO during a task switch (or any other complex operation). */ - if (ret || vcpu->mmio_needed) { - vcpu->mmio_needed = false; - vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; - vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION; - vcpu->run->internal.ndata = 0; - return 0; - } + if (ret || vcpu->mmio_needed) + goto unhandled_task_switch; kvm_rip_write(vcpu, ctxt->eip); kvm_set_rflags(vcpu, ctxt->eflags); return 1; + +unhandled_task_switch: + vcpu->mmio_needed = false; + vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION; + vcpu->run->internal.ndata = 0; + return 0; } EXPORT_SYMBOL_GPL(kvm_task_switch); |