[PATCHv3 00/14] x86/tdx: Add kexec support

[Baoquan He]

On 11/16/23 at 10:17pm, Baoquan He wrote:
> On 11/16/23 at 03:56pm, Kirill A. Shutemov wrote:
> > On Thu, Nov 16, 2023 at 08:10:47PM +0800, Baoquan He wrote:
> > > On 11/15/23 at 03:00pm, Kirill A. Shutemov wrote:
> > > > The patchset adds bits and pieces to get kexec (and crashkernel) work on
> > > > TDX guest.
> > > 
> > > I finally got a machine of intel-eaglestream-spr as host and built a
> > > tdx guest to give it a shot, the kexec reboot is working very well,
> > > while kdump kernel always failed to boot up. I only built kernel and
> > > installed it on tdx guest.
> > > ------------------------------------------
> > > [    1.422500] Run /init as init process
> > > [    1.423073] Failed to execute /init (error -2)
> > > [    1.423759] Run /sbin/init as init process
> > > [    1.424370] Run /etc/init as init process
> > > [    1.424969] Run /bin/init as init process
> > > [    1.425588] Run /bin/sh as init process
> > > [    1.426150] Kernel panic - not syncing: No working init found.  Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance.
> > > [    1.428122] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.7.0-rc1-00014-gbdba31ba3cec #3
> > > [    1.429232] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 2/2/2022
> > > [    1.430328] Call Trace:
> > > [    1.430717]  <TASK>
> > > [    1.431041]  dump_stack_lvl+0x33/0x50
> > > [    1.431581]  panic+0x324/0x340
> > > [    1.432037]  ? __pfx_kernel_init+0x10/0x10
> > > [    1.432629]  kernel_init+0x174/0x1c0
> > > [    1.433149]  ret_from_fork+0x2d/0x50
> > > [    1.433690]  ? __pfx_kernel_init+0x10/0x10
> > > [    1.434277]  ret_from_fork_asm+0x1b/0x30
> > > [    1.434850]  </TASK>
> > > [    1.435345] Kernel Offset: disabled
> > > [    1.439216] Rebooting in 10 seconds..
> > > qemu-kvm: cpus are not resettable, terminating
> > 
> > Could you shared your kernel config and details about your setup (qemu
> > command, kernel command line, ...)?
> 
> We followed tdx-tools README to setup the environment and built host and
> guest kernel, qemu command is as below. I copied the
> tdx-tools/build/rhel-9/intel-mvp-tdx-kernel/tdx-base.config to the
> latest upstream linxu kernel then execute 'make olddefconfig'. Because
> your patchset can't be applied to the stable kernel with the 731
> patches.
> 
> cd /home/root/tdx-tools
> ./start-qemu.sh -i /home/root/guest_tdx.qcow2 -b grub

This is the qemu command when execute above line of command, just for
your reference if you happen to not take this way.

[root at intel-eaglestream-spr-03 tdx-tools]# ./start-qemu.sh -i /home/root/guest_tdx.qcow2 -b grub
WARN: Using HVC console for grub, could not accept key input in grub menu
=========================================
Guest Image       : /home/root/guest_tdx.qcow2
Kernel binary     : 
OVMF              : /usr/share/qemu/OVMF.fd
VM Type           : td
CPUS              : 1
Boot type         : grub
Monitor port      : 9001
Enable vsock      : false
Enable debug      : false
Console           : HVC
=========================================
Remapping CTRL-C to CTRL-]
Launch VM:
/usr/libexec/qemu-kvm -accel kvm -name process=tdxvm,debug-threads=on -m 2G -vga none -monitor pty -no-hpet -nodefaults -drive file=/home/root/guest_tdx.qcow2,if=virtio,format=qcow2 -monitor telnet:127.0.0.1:9001,server,nowait -bios /usr/share/qemu/OVMF.fd -object tdx-guest,sept-ve-disable=on,id=tdx -object memory-backend-memfd-private,id=ram1,size=2G -cpu host,-kvm-steal-time,pmu=off -machine q35,kernel_irqchip=split,confidential-guest-support=tdx,memory-backend=ram1 -device virtio-net-pci,netdev=mynet0 -netdev user,id=mynet0,net=10.0.2.0/24,dhcpstart=10.0.2.15,hostfwd=tcp::10026-:22 -smp 1 -chardev stdio,id=mux,mux=on,logfile=/home/root/tdx-tools/vm_log_2023-11-16T0658.log -device virtio-serial,romfile= -device virtconsole,chardev=mux -monitor chardev:mux -serial chardev:mux -nographic
char device redirected to /dev/pts/1 (label compat_monitor0)