From: Paolo Bonzini Date: Thu, 27 Feb 2014 21:54:11 +0000 (+0100) Subject: kvm, vmx: Really fix lazy FPU on nested guest X-Git-Tag: v3.15-rc1~118^2~38 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=ccf9844e5d99c1ee9a5b8c4f1332ac5211cbce03;p=linux.git kvm, vmx: Really fix lazy FPU on nested guest Commit e504c9098ed6 (kvm, vmx: Fix lazy FPU on nested guest, 2013-11-13) highlighted a real problem, but the fix was subtly wrong. nested_read_cr0 is the CR0 as read by L2, but here we want to look at the CR0 value reflecting L1's setup. In other words, L2 might think that TS=0 (so nested_read_cr0 has the bit clear); but if L1 is actually running it with TS=1, we should inject the fault into L1. The effective value of CR0 in L2 is contained in vmcs12->guest_cr0, use it. Fixes: e504c9098ed6acd9e1079c5e10e4910724ad429f Reported-by: Kashyap Chamarty Reported-by: Stefan Bader Tested-by: Kashyap Chamarty Tested-by: Anthoine Bourgeois Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 83ee24f74a69..53c324f3cc5e 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -6699,7 +6699,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu) else if (is_page_fault(intr_info)) return enable_ept; else if (is_no_device(intr_info) && - !(nested_read_cr0(vmcs12) & X86_CR0_TS)) + !(vmcs12->guest_cr0 & X86_CR0_TS)) return 0; return vmcs12->exception_bitmap & (1u << (intr_info & INTR_INFO_VECTOR_MASK));