| Message ID | 1488600212-24037-1-git-send-email-wanpeng.li@hotmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, Mar 4, 2017 at 5:03 AM, Wanpeng Li <kernellwp@gmail.com> wrote: > Reported by syzkaller: > > WARNING: CPU: 1 PID: 27742 at arch/x86/kvm/vmx.c:11029 > nested_vmx_vmexit+0x5c35/0x74d0 arch/x86/kvm/vmx.c:11029 > CPU: 1 PID: 27742 Comm: a.out Not tainted 4.10.0+ #229 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:15 [inline] > dump_stack+0x2ee/0x3ef lib/dump_stack.c:51 > panic+0x1fb/0x412 kernel/panic.c:179 > __warn+0x1c4/0x1e0 kernel/panic.c:540 > warn_slowpath_null+0x2c/0x40 kernel/panic.c:583 > nested_vmx_vmexit+0x5c35/0x74d0 arch/x86/kvm/vmx.c:11029 > vmx_leave_nested arch/x86/kvm/vmx.c:11136 [inline] > vmx_set_msr+0x1565/0x1910 arch/x86/kvm/vmx.c:3324 > kvm_set_msr+0xd4/0x170 arch/x86/kvm/x86.c:1099 > do_set_msr+0x11e/0x190 arch/x86/kvm/x86.c:1128 > __msr_io arch/x86/kvm/x86.c:2577 [inline] > msr_io+0x24b/0x450 arch/x86/kvm/x86.c:2614 > kvm_arch_vcpu_ioctl+0x35b/0x46a0 arch/x86/kvm/x86.c:3497 > kvm_vcpu_ioctl+0x232/0x1120 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2721 > vfs_ioctl fs/ioctl.c:43 [inline] > do_vfs_ioctl+0x1bf/0x1790 fs/ioctl.c:683 > SYSC_ioctl fs/ioctl.c:698 [inline] > SyS_ioctl+0x8f/0xc0 fs/ioctl.c:689 > entry_SYSCALL_64_fastpath+0x1f/0xc2 > > The syzkaller folks reported a nested_run_pending warning during userspace clear VMX > capability which is exposed to L1 before. > > The warning gets thrown while doing > > (*(uint32_t*)0x20aecfe8 = (uint32_t)0x1); > (*(uint32_t*)0x20aecfec = (uint32_t)0x0); > (*(uint32_t*)0x20aecff0 = (uint32_t)0x3a); > (*(uint32_t*)0x20aecff4 = (uint32_t)0x0); > (*(uint64_t*)0x20aecff8 = (uint64_t)0x0); > r[29] = syscall(__NR_ioctl, r[4], 0x4008ae89ul, > 0x20aecfe8ul, 0, 0, 0, 0, 0, 0); > > i.e. KVM_SET_MSR ioctl with > > struct kvm_msrs { > .nmsrs = 1, > .pad = 0, > .entries = { > {.index = MSR_IA32_FEATURE_CONTROL, > .reserved = 0, > .data = 0} > } > } > > The VMLANCH/VMRESUME emulation should be stopped since the CPU is going to reset here. > This patch resets the nested_run_pending since the CPU is going to be reset hence there > should be nothing pending. Applied on bots. Thanks! > Reported-by: Dmitry Vyukov <dvyukov@google.com> > Suggested-by: Radim Krčmář <rkrcmar@redhat.com> > Cc: Paolo Bonzini <pbonzini@redhat.com> > Cc: Radim Krčmář <rkrcmar@redhat.com> > Cc: Dmitry Vyukov <dvyukov@google.com> > Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> > --- > arch/x86/kvm/vmx.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 283aa86..b4a757369 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -3310,8 +3310,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > FEATURE_CONTROL_LOCKED && !msr_info->host_initiated)) > return 1; > vmx->msr_ia32_feature_control = data; > - if (msr_info->host_initiated && data == 0) > + if (msr_info->host_initiated && data == 0) { > + vmx->nested.nested_run_pending = 0; > vmx_leave_nested(vcpu); > + } > break; > case MSR_IA32_VMX_BASIC ... MSR_IA32_VMX_VMFUNC: > if (!msr_info->host_initiated) > -- > 2.7.4 >
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 283aa86..b4a757369 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -3310,8 +3310,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) FEATURE_CONTROL_LOCKED && !msr_info->host_initiated)) return 1; vmx->msr_ia32_feature_control = data; - if (msr_info->host_initiated && data == 0) + if (msr_info->host_initiated && data == 0) { + vmx->nested.nested_run_pending = 0; vmx_leave_nested(vcpu); + } break; case MSR_IA32_VMX_BASIC ... MSR_IA32_VMX_VMFUNC: if (!msr_info->host_initiated)
Reported by syzkaller: WARNING: CPU: 1 PID: 27742 at arch/x86/kvm/vmx.c:11029 nested_vmx_vmexit+0x5c35/0x74d0 arch/x86/kvm/vmx.c:11029 CPU: 1 PID: 27742 Comm: a.out Not tainted 4.10.0+ #229 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:15 [inline] dump_stack+0x2ee/0x3ef lib/dump_stack.c:51 panic+0x1fb/0x412 kernel/panic.c:179 __warn+0x1c4/0x1e0 kernel/panic.c:540 warn_slowpath_null+0x2c/0x40 kernel/panic.c:583 nested_vmx_vmexit+0x5c35/0x74d0 arch/x86/kvm/vmx.c:11029 vmx_leave_nested arch/x86/kvm/vmx.c:11136 [inline] vmx_set_msr+0x1565/0x1910 arch/x86/kvm/vmx.c:3324 kvm_set_msr+0xd4/0x170 arch/x86/kvm/x86.c:1099 do_set_msr+0x11e/0x190 arch/x86/kvm/x86.c:1128 __msr_io arch/x86/kvm/x86.c:2577 [inline] msr_io+0x24b/0x450 arch/x86/kvm/x86.c:2614 kvm_arch_vcpu_ioctl+0x35b/0x46a0 arch/x86/kvm/x86.c:3497 kvm_vcpu_ioctl+0x232/0x1120 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2721 vfs_ioctl fs/ioctl.c:43 [inline] do_vfs_ioctl+0x1bf/0x1790 fs/ioctl.c:683 SYSC_ioctl fs/ioctl.c:698 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:689 entry_SYSCALL_64_fastpath+0x1f/0xc2 The syzkaller folks reported a nested_run_pending warning during userspace clear VMX capability which is exposed to L1 before. The warning gets thrown while doing (*(uint32_t*)0x20aecfe8 = (uint32_t)0x1); (*(uint32_t*)0x20aecfec = (uint32_t)0x0); (*(uint32_t*)0x20aecff0 = (uint32_t)0x3a); (*(uint32_t*)0x20aecff4 = (uint32_t)0x0); (*(uint64_t*)0x20aecff8 = (uint64_t)0x0); r[29] = syscall(__NR_ioctl, r[4], 0x4008ae89ul, 0x20aecfe8ul, 0, 0, 0, 0, 0, 0); i.e. KVM_SET_MSR ioctl with struct kvm_msrs { .nmsrs = 1, .pad = 0, .entries = { {.index = MSR_IA32_FEATURE_CONTROL, .reserved = 0, .data = 0} } } The VMLANCH/VMRESUME emulation should be stopped since the CPU is going to reset here. This patch resets the nested_run_pending since the CPU is going to be reset hence there should be nothing pending. Reported-by: Dmitry Vyukov <dvyukov@google.com> Suggested-by: Radim Krčmář <rkrcmar@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> --- arch/x86/kvm/vmx.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)