I am hitting the below failure with v6.15 (I tried other kernel versions
with similar results). I disabled CONFIG_PROTECTED_NVHE_STACKTRACE
because with CONFIG_NVHE_EL2_DEBUG, the stack was pointing at
hyp_assert_lock_held() .

[    0.664457] kvm [1]: nVHE hyp panic at: [<ffff80008050b10c>] __kvm_nvhe_handle_trap+0x34/0x10c!
[    0.664538] kvm [1]: Cannot dump pKVM nVHE stacktrace: !CONFIG_PROTECTED_NVHE_STACKTRACE
[    0.664566] kvm [1]: Hyp Offset: 0xffff000007c00000
[    0.664631] Kernel panic - not syncing: HYP panic:
[    0.664631] PS:614023c9 PC:000080007890b10c ESR:0000000096000007
[    0.664631] FAR:0000800078c252f0 HPFAR:0000000000000000 PAR:0000000000000000
[    0.664631] VCPU:0000000000000000
[    0.664938] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.15.0-rc1 #594 NONE 
[    0.665068] Hardware name: FVP Base RevC (DT)
[    0.665140] Call trace:
[    0.665196]  show_stack+0x18/0x24 (C)
[    0.665346]  dump_stack_lvl+0x3c/0x80
[    0.665468]  dump_stack+0x18/0x24
[    0.665588]  panic+0x124/0x2d8
[    0.665699]  nvhe_hyp_panic_handler+0x108/0x180
[    0.665825]  do_pkvm_init+0xb0/0x124
[    0.665957]  do_pkvm_init+0xb0/0x124
[    0.666089]  kvm_hyp_init_protection+0x5c/0x6c
[    0.666226]  init_hyp_mode+0x760/0x790
[    0.666362]  kvm_arm_init+0xac/0x23c
[    0.666492]  do_one_initcall+0xa0/0x1f0
[    0.666617]  do_initcall_level+0x8c/0xac
[    0.666753]  do_initcalls+0x54/0x94
[    0.666885]  do_basic_setup+0x18/0x24
[    0.667019]  kernel_init_freeable+0xc0/0x10c
[    0.667157]  kernel_init+0x20/0x118
[    0.667271]  ret_from_fork+0x10/0x20
[    0.667400] SMP: stopping secondary CPUs
[    0.667475] Kernel Offset: disabled
[    0.667534] CPU features: 0x0000,00000140,064dc298,cb7a552f
[    0.667619] Memory Limit: none
[    0.667681] ---[ end Kernel panic - not syncing: HYP panic:
[    0.667681] PS:614023c9 PC:000080007890b10c ESR:0000000096000007
[    0.667681] FAR:0000800078c252f0 HPFAR:0000000000000000 PAR:0000000000000000
[    0.667681] VCPU:0000000000000000 ]

I was able to locate a .config that make the pkvm work, But i am not
able to identify which config dependency is making the difference. I am
attaching below the working and non working kernel configs. I am using
FVP to test this.