From 3c6e099fa15fdb6fb1892199ed8709012e1294f2 Mon Sep 17 00:00:00 2001 From: Jim Mattson Date: Thu, 13 Sep 2018 11:54:48 -0700 Subject: [PATCH] KVM: nVMX: Always reflect #NM VM-exits to L1 When bit 3 (corresponding to CR0.TS) of the VMCS12 cr0_guest_host_mask field is clear, the VMCS12 guest_cr0 field does not necessarily hold the current value of the L2 CR0.TS bit, so the code that checked for L2's CR0.TS bit being set was incorrect. Moreover, I'm not sure that the CR0.TS check was adequate. (What if L2's CR0.EM was set, for instance?) Fortunately, lazy FPU has gone away, so L0 has lost all interest in intercepting #NM exceptions. See commit bd7e5b0899a4 ("KVM: x86: remove code for lazy FPU handling"). Therefore, there is no longer any question of which hypervisor gets first dibs. The #NM VM-exit should always be reflected to L1. (Note that the corresponding bit must be set in the VMCS12 exception_bitmap field for there to be an #NM VM-exit at all.) Fixes: ccf9844e5d99c ("kvm, vmx: Really fix lazy FPU on nested guest") Reported-by: Abhiroop Dabral Signed-off-by: Jim Mattson Reviewed-by: Peter Shier Tested-by: Abhiroop Dabral Reviewed-by: Liran Alon Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index eee1b60023fd..b967f89963bf 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -1613,11 +1613,6 @@ static inline bool is_page_fault(u32 intr_info) return is_exception_n(intr_info, PF_VECTOR); } -static inline bool is_no_device(u32 intr_info) -{ - return is_exception_n(intr_info, NM_VECTOR); -} - static inline bool is_invalid_opcode(u32 intr_info) { return is_exception_n(intr_info, UD_VECTOR); @@ -9653,9 +9648,6 @@ static bool nested_vmx_exit_reflected(struct kvm_vcpu *vcpu, u32 exit_reason) return false; else if (is_page_fault(intr_info)) return !vmx->vcpu.arch.apf.host_apf_reason && enable_ept; - else if (is_no_device(intr_info) && - !(vmcs12->guest_cr0 & X86_CR0_TS)) - return false; else if (is_debug(intr_info) && vcpu->guest_debug & (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP)) -- 2.30.2