问题描述
我正在尝试在qemu中引导Arch Linux，并将console=ttyS0添加到内核引导参数中。我下载了.iso，解压缩并运行以下命令
qemu-system-x86_64 -accel hvf -cpu host -m 2048 -nographic -append "console=ttyS0" -kernel arch/boot/x86_64/vmlinuz-linux -initrd arch/boot/x86_64/initramfs-linux.img
结果，我得到以下输出
SeaBIOS (version rel-1.13.0-48-gd9c812dda519-prebuilt.qemu.org)
iPXE (http://ipxe.org) 00:03.0 CA00 PCI2.10 PnP PMM+7FF8F130+7FEEF130 CA00
Booting from ROM...
Probing EDD (edd=off to disable)... o
[ 0.233432] invalid opcode: 0000 [#1] PREEMPT SMP nopTI
[ 0.233903] cpu: 0 PID: 13 Comm: migration/0 Not tainted 5.8.12-arch1-1 #1
[ 0.234504] Hardware name: QEMU Standard PC (i440FX + PIIX,1996),BIOS rel-1.13.0-48-gd9c812dda519-prebuilt.qemu.org 04/01/2014
[ 0.235521] RIP: 0010:read_tsc+0x0/0x10
[ 0.235870] Code: cc cc cc cc cc cc cc cc cc cc 8b 05 b6 23 93 01 c3 66 0f 1f 84 00 00 00 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 41
[ 0.236718] RSP: 0000:ffffaf1480073e28 EFLAGS: 00010002
[ 0.236718] RAX: ffffffff9da35aa0 RBX: ffffffff9f227520 RCX: 0000003b9aca0000
[ 0.236718] RDX: 0000003b9aca0000 RSI: 0000003b9aca0000 RDI: ffffffff9f227520
[ 0.236718] RBP: ffffffff9f25d1a0 R08: 0000000000000000 R09: 0000000000000004
[ 0.236718] R10: 0000000000000204 R11: 0000000000000000 R12: 0000000000000002
[ 0.236718] R13: ffffffff9f369520 R14: 0000000000000000 R15: 0000000000000003
[ 0.236718] FS: 0000000000000000(0000) GS:ffff9d957b000000(0000) knlGS:0000000000000000
[ 0.236718] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.236718] CR2: 0000000000000000 CR3: 000000004200a001 CR4: 00000000003606f0
[ 0.236718] Call Trace:
[ 0.236718] tk_setup_internals.constprop.0+0x39/0x150
[ 0.236718] change_clocksource+0x5b/0xc0
[ 0.236718] multi_cpu_stop+0x6b/0x110
[ 0.236718] ? stop_machine_yield+0x10/0x10
[ 0.236718] cpu_stopper_thread+0x72/0x100
[ 0.236718] ? smpboot_register_percpu_thread+0xe0/0xe0
[ 0.236718] smpboot_thread_fn+0x19a/0x230
[ 0.236718] kthread+0x142/0x160
[ 0.236718] ? __kthread_bind_mask+0x60/0x60
[ 0.236718] ret_from_fork+0x1f/0x30
[ 0.236718] Modules linked in:
[ 0.236718] ---[ end trace 18ea92f06c5f9ac2 ]---
[ 0.236718] RIP: 0010:read_tsc+0x0/0x10
[ 0.236718] Code: cc cc cc cc cc cc cc cc cc cc 8b 05 b6 23 93 01 c3 66 0f 1f 84 00 00 00 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 41
[ 0.236718] RSP: 0000:ffffaf1480073e28 EFLAGS: 00010002
[ 0.236718] RAX: ffffffff9da35aa0 RBX: ffffffff9f227520 RCX: 0000003b9aca0000
[ 0.236718] RDX: 0000003b9aca0000 RSI: 0000003b9aca0000 RDI: ffffffff9f227520
[ 0.236718] RBP: ffffffff9f25d1a0 R08: 0000000000000000 R09: 0000000000000004
[ 0.236718] R10: 0000000000000204 R11: 0000000000000000 R12: 0000000000000002
[ 0.236718] R13: ffffffff9f369520 R14: 0000000000000000 R15: 0000000000000003
[ 0.236718] FS: 0000000000000000(0000) GS:ffff9d957b000000(0000) knlGS:0000000000000000
[ 0.236718] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.236718] CR2: 0000000000000000 CR3: 000000004200a001 CR4: 00000000003606f0
[ 0.236718] note: migration/0[13] exited with preempt_count 2
我试图通过将pti=off spectre_v2=off添加到引导参数来禁用PTI，但是结果是完全一样的。
解决方法
关键似乎在这一行：
[ 0.236718] RIP: 0010:read_tsc+0x0/0x10
尝试将--cpu更改为--cpu host,-rdtscp，这将在发布给Linux guest虚拟机的CPU标志中禁用TSC支持。您可能需要/想要在内核参数中添加clocksource=hpet，以便随后为来宾提供稳定的时间源。