From: Avi Kivity Date: Sun, 13 May 2012 16:53:23 +0000 (+0300) Subject: KVM: VMX: Fix %ds/%es clobber X-Git-Tag: upstream/snapshot3+hdmi~7382^2~8 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=512d5649e8dc3ed36f2ebf0818da64a4d4c2544a;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git KVM: VMX: Fix %ds/%es clobber The vmx exit code unconditionally restores %ds and %es to __USER_DS. This can override the user's values, since %ds and %es are not saved and restored in x86_64 syscalls. In practice, this isn't dangerous since nobody uses segment registers in long mode, least of all programs that use KVM. Signed-off-by: Avi Kivity Signed-off-by: Marcelo Tosatti --- diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 3062ea9..f2ee016 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -6102,7 +6102,10 @@ static void atomic_switch_perf_msrs(struct vcpu_vmx *vmx) static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); + u16 _ds, _es; + savesegment(ds, _ds); + savesegment(es, _es); if (is_guest_mode(vcpu) && !vmx->nested.nested_run_pending) { struct vmcs12 *vmcs12 = get_vmcs12(vcpu); if (vmcs12->idt_vectoring_info_field & @@ -6263,7 +6266,8 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) } } - asm("mov %0, %%ds; mov %0, %%es" : : "r"(__USER_DS)); + loadsegment(ds, _ds); + loadsegment(es, _es); vmx->loaded_vmcs->launched = 1; vmx->exit_reason = vmcs_read32(VM_EXIT_REASON);