2018-02-06 2:24 GMT+08:00 Jim Mattson <jmatt...@google.com>: > [Resending as plain text] > > On Mon, Feb 5, 2018 at 10:21 AM Jim Mattson <jmatt...@google.com> wrote: > >> This is incorrect. In the event of an early VM-entry failure (e.g. a >> VM-entry failure for "VM entry with invalid control field(s)"), no host >> state should be loaded from the VMCS12. Of course, no guest state should >> have been loaded from the VMCS12 either, but that's a problem we have with >> deferring some VMCS12 control field checks to the hardware. > >> CR4 should be unchanged from the time of the VMLAUNCH/VMRESUME. There is
This is effective one, what I restore in this patch is achitectural/guest visible. Regards, Wanpeng Li >> no guarantee that vmcs12->host_cr4 holds the correct value. > > >> On Mon, Feb 5, 2018 at 3:05 AM Wanpeng Li <kernel...@gmail.com> wrote: > >>> From: Wanpeng Li <wanpen...@tencent.com> > >>> In L0, Haswell client host: > >>> nested_vmx_exit_reflected failed vm entry 7 >>> WARNING: CPU: 6 PID: 6797 at kvm/arch/x86/kvm//vmx.c:6206 >>> handle_desc+0x2d/0x40 [kvm_intel] >>> CPU: 6 PID: 6797 Comm: qemu-system-x86 Tainted: G W OE >>> 4.15.0+ #4 >>> RIP: 0010:handle_desc+0x2d/0x40 [kvm_intel] >>> Call Trace: >>> vmx_handle_exit+0xbd/0xe20 [kvm_intel] >>> ? kvm_arch_vcpu_ioctl_run+0xcde/0x1c00 [kvm] >>> kvm_arch_vcpu_ioctl_run+0xd5a/0x1c00 [kvm] >>> kvm_vcpu_ioctl+0x3e9/0x720 [kvm] >>> ? kvm_vcpu_ioctl+0x3e9/0x720 [kvm] >>> ? __fget+0xfc/0x210 >>> ? __fget+0xfc/0x210 >>> do_vfs_ioctl+0xa4/0x6a0 >>> ? __fget+0x11d/0x210 >>> SyS_ioctl+0x79/0x90 >>> entry_SYSCALL_64_fastpath+0x25/0x9c > >>> This can be reproduced by running kvm-unit-tests/run_tests.sh >>> vmx_controls in >>> L1. UMIP CPUID bit is exposed to the L1 UMIP aware guest since it is >>> emulated >>> by enabling descriptor-table exits on L0. There is a vmentry fail when >>> L0 tries to run L2 directly, the L1 guest architectural CR4 is not >>> restored >>> after this failure since commit 4f350c6dbcb (kvm: nVMX: Handle deferred >>> early >>> VMLAUNCH/VMRESUME failure properly). The L2 is kvm-unit-tests which will >>> not >>> write CR4 w/ X86_CR4_UMIP bit. After another L1 access descriptor vmexit, >>> we >>> check L2's architectural CR4 instead of L1's architectural CR4. This >>> patch >>> fixes it by restoring L1's architectural CR4 after L0's VMLAUNCH/VMRESUME >>> failure. > >>> Cc: Paolo Bonzini <pbonz...@redhat.com> >>> Cc: Radim Krčmář <rkrc...@redhat.com> >>> Signed-off-by: Wanpeng Li <wanpen...@tencent.com> >>> --- >>> arch/x86/kvm/vmx.c | 1 + >>> 1 file changed, 1 insertion(+) > >>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >>> index 23789c9..9fc0492 100644 >>> --- a/arch/x86/kvm/vmx.c >>> +++ b/arch/x86/kvm/vmx.c >>> @@ -11633,6 +11633,7 @@ static void nested_vmx_vmexit(struct kvm_vcpu >>> *vcpu, u32 exit_reason, >>> */ >>> nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD); > >>> + vcpu->arch.cr4 = vmcs12->host_cr4; >>> load_vmcs12_mmu_host_state(vcpu, vmcs12); > >>> /* >>> -- >>> 2.7.4
