L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.
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WARNING: CPU: 0 PID: 4392 at arch/x86/kvm/../../../virt/kvm/kvm_main.c:3126 kvm_read_guest_offset_cached+0x3b8/0x410 virt/kvm/kvm_main.c:3126
Modules linked in:
CPU: 0 PID: 4392 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
RIP: 0010:kvm_read_guest_offset_cached+0x3b8/0x410 virt/kvm/kvm_main.c:3126
Code: 00 c6 05 bd 9a 50 0d 01 48 c7 c7 a0 ed 21 8a be 7a 03 00 00 48 c7 c2 40 cd 21 8a e8 d2 f7 b5 08 e9 e7 fc ff ff e8 c8 7d 70 00 <0f> 0b b8 ea ff ff ff e9 72 ff ff ff 4c 8b 74 24 10 4c 03 34 24 e8
RSP: 0018:ffffc9000320f420 EFLAGS: 00010293
RAX: ffffffff8108afc8 RBX: 0000000000000038 RCX: ffff88802b081dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000038
RBP: 0000000000000000 R08: ffffc900023b3f4b R09: 1ffff920004767e9
R10: dffffc0000000000 R11: fffff520004767ea R12: ffff88807c145d48
R13: ffff88805da60000 R14: ffffc900023a9000 R15: 0000000000000038
FS:  000055556bb47500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002000 CR3: 0000000075fda000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kvm_hv_get_assist_page+0xfa/0x120 arch/x86/kvm/hyperv.c:914
 nested_enlightened_vmentry+0xd2/0x1a0 arch/x86/kvm/vmx/evmcs.c:315
 nested_vmx_handle_enlightened_vmptrld+0xf3/0x630 arch/x86/kvm/vmx/nested.c:1994
 nested_get_evmcs_page arch/x86/kvm/vmx/nested.c:3170 [inline]
 vmx_get_nested_state_pages+0x78/0x2b0 arch/x86/kvm/vmx/nested.c:3289
 vcpu_enter_guest+0x386/0x6f70 arch/x86/kvm/x86.c:9778
 vcpu_run arch/x86/kvm/x86.c:10192 [inline]
 kvm_arch_vcpu_ioctl_run+0x804/0x1e40 arch/x86/kvm/x86.c:10432
 kvm_vcpu_ioctl+0x8f2/0xc10 virt/kvm/kvm_main.c:3895
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f3350294f19
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe3e2d28b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f3350511fa0 RCX: 00007f3350294f19
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00007f3350323f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3350511fac R14: 00007f3350511fa0 R15: 00007f3350511fa0
 </TASK>