? 2012?10?31? 17:01, Hatayama, Daisuke ??: > > >> -----Original Message----- >> From: kexec-bounces at lists.infradead.org >> [mailto:kexec-bounces at lists.infradead.org] On Behalf Of zhangyanfei >> Sent: Wednesday, October 31, 2012 12:34 PM >> To: x86 at kernel.org; kexec at lists.infradead.org; Avi Kivity; Marcelo >> Tosatti >> Cc: linux-kernel at vger.kernel.org; kvm at vger.kernel.org >> Subject: [PATCH v3 2/2] KVM: make crash_clear_loaded_vmcss valid when >> loading kvm_intel module >> >> Signed-off-by: Zhang Yanfei <zhangyanfei at cn.fujitsu.com> > > [...] > >> @@ -7230,6 +7231,10 @@ static int __init vmx_init(void) >> if (r) >> goto out3; >> >> +#ifdef CONFIG_KEXEC >> + crash_clear_loaded_vmcss = vmclear_local_loaded_vmcss; >> +#endif >> + > > Assignment here cannot cover the case where NMI is initiated after VMX is on in kvm_init and before vmclear_local_loaded_vmcss is assigned, though rare but can happen. > By saying "VMX is on in kvm init", you mean kvm_init enables the VMX feature in the logical processor? No, only there is a vcpu to be created, kvm will enable the VMX feature. I think there is no difference with this assignment before or after kvm_init because the vmcs linked list must be empty before vmx_init is finished. Thanks Zhang Yanfei > What does happen if calling vmclear_local_loaded_vmcss before kvm_init? I think it no problem since the list is initially empty. > >> vmx_disable_intercept_for_msr(MSR_FS_BASE, false); >> vmx_disable_intercept_for_msr(MSR_GS_BASE, false); >> vmx_disable_intercept_for_msr(MSR_KERNEL_GS_BASE, true); >> @@ -7265,6 +7270,10 @@ static void __exit vmx_exit(void) >> free_page((unsigned long)vmx_io_bitmap_b); >> free_page((unsigned long)vmx_io_bitmap_a); >> >> +#ifdef CONFIG_KEXEC >> + crash_clear_loaded_vmcss = NULL; >> +#endif >> + >> kvm_exit(); >> } > > Also, this is converse to the above. > > Thanks. > HATAYAMA, Daisuke > >
