From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
[ Upstream commit 2f707d97982286b307ef2a9b034e19aabc1abb56 ]
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@xxxxxxxxxx>
Suggested-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
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 aa8776848183..88b92d948b41 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10556,8 +10556,10 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
*/
static void vmx_leave_nested(struct kvm_vcpu *vcpu)
{
- if (is_guest_mode(vcpu))
+ if (is_guest_mode(vcpu)) {
+ to_vmx(vcpu)->nested.nested_run_pending = 0;
nested_vmx_vmexit(vcpu, -1, 0, 0);
+ }
free_nested(to_vmx(vcpu));
}
--
2.11.0