Messages in this thread | | | Date | Tue, 11 Jul 2023 09:36:46 +0100 | From | Marc Zyngier <> | Subject | Re: [PATCH] KVM: arm64: Handle kvm_arm_init failure correctly in finalize_pkvm |
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On Tue, 04 Jul 2023 20:32:43 +0100, Sudeep Holla <sudeep.holla@arm.com> wrote: > > Currently there is no synchronisation between finalize_pkvm() and > kvm_arm_init() initcalls. The finalize_pkvm() proceeds happily even if > kvm_arm_init() fails resulting in the following warning on all the CPUs > and eventually a HYP panic: > > | kvm [1]: IPA Size Limit: 48 bits > | kvm [1]: Failed to init hyp memory protection > | kvm [1]: error initializing Hyp mode: -22 > | > | <snip> > | > | WARNING: CPU: 0 PID: 0 at arch/arm64/kvm/pkvm.c:226 _kvm_host_prot_finalize+0x30/0x50 > | Modules linked in: > | CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.4.0 #237 > | Hardware name: FVP Base RevC (DT) > | pstate: 634020c5 (nZCv daIF +PAN -UAO +TCO +DIT -SSBS BTYPE=--) > | pc : _kvm_host_prot_finalize+0x30/0x50 > | lr : __flush_smp_call_function_queue+0xd8/0x230 > | > | Call trace: > | _kvm_host_prot_finalize+0x3c/0x50 > | on_each_cpu_cond_mask+0x3c/0x6c > | pkvm_drop_host_privileges+0x4c/0x78 > | finalize_pkvm+0x3c/0x5c > | do_one_initcall+0xcc/0x240 > | do_initcall_level+0x8c/0xac > | do_initcalls+0x54/0x94 > | do_basic_setup+0x1c/0x28 > | kernel_init_freeable+0x100/0x16c > | kernel_init+0x20/0x1a0 > | ret_from_fork+0x10/0x20 > | Failed to finalize Hyp protection: -22 > | dtb=fvp-base-revc.dtb > | kvm [95]: nVHE hyp BUG at: arch/arm64/kvm/hyp/nvhe/mem_protect.c:540! > | kvm [95]: nVHE call trace: > | kvm [95]: [<ffff800081052984>] __kvm_nvhe_hyp_panic+0xac/0xf8 > | kvm [95]: [<ffff800081059644>] __kvm_nvhe_handle_host_mem_abort+0x1a0/0x2ac > | kvm [95]: [<ffff80008105511c>] __kvm_nvhe_handle_trap+0x4c/0x160 > | kvm [95]: [<ffff8000810540fc>] __kvm_nvhe___skip_pauth_save+0x4/0x4 > | kvm [95]: ---[ end nVHE call trace ]--- > | kvm [95]: Hyp Offset: 0xfffe8db00ffa0000 > | Kernel panic - not syncing: HYP panic: > | PS:a34023c9 PC:0000f250710b973c ESR:00000000f2000800 > | FAR:ffff000800cb00d0 HPFAR:000000000880cb00 PAR:0000000000000000 > | VCPU:0000000000000000 > | CPU: 3 PID: 95 Comm: kworker/u16:2 Tainted: G W 6.4.0 #237 > | Hardware name: FVP Base RevC (DT) > | Workqueue: rpciod rpc_async_schedule > | Call trace: > | dump_backtrace+0xec/0x108 > | show_stack+0x18/0x2c > | dump_stack_lvl+0x50/0x68 > | dump_stack+0x18/0x24 > | panic+0x138/0x33c > | nvhe_hyp_panic_handler+0x100/0x184 > | new_slab+0x23c/0x54c > | ___slab_alloc+0x3e4/0x770 > | kmem_cache_alloc_node+0x1f0/0x278 > | __alloc_skb+0xdc/0x294 > | tcp_stream_alloc_skb+0x2c/0xf0 > | tcp_sendmsg_locked+0x3d0/0xda4 > | tcp_sendmsg+0x38/0x5c > | inet_sendmsg+0x44/0x60 > | sock_sendmsg+0x1c/0x34 > | xprt_sock_sendmsg+0xdc/0x274 > | xs_tcp_send_request+0x1ac/0x28c > | xprt_transmit+0xcc/0x300 > | call_transmit+0x78/0x90 > | __rpc_execute+0x114/0x3d8 > | rpc_async_schedule+0x28/0x48 > | process_one_work+0x1d8/0x314 > | worker_thread+0x248/0x474 > | kthread+0xfc/0x184 > | ret_from_fork+0x10/0x20 > | SMP: stopping secondary CPUs > | Kernel Offset: 0x57c5cb460000 from 0xffff800080000000 > | PHYS_OFFSET: 0x80000000 > | CPU features: 0x00000000,1035b7a3,ccfe773f > | Memory Limit: none > | ---[ end Kernel panic - not syncing: HYP panic: > | PS:a34023c9 PC:0000f250710b973c ESR:00000000f2000800 > | FAR:ffff000800cb00d0 HPFAR:000000000880cb00 PAR:0000000000000000 > | VCPU:0000000000000000 ]--- > > Fix it by checking for the successfull initialisation of kvm_arm_init() > in finalize_pkvm() before proceeding any futher. > > Fixes: 87727ba2bb05 ("KVM: arm64: Ensure CPU PMU probes before pKVM host de-privilege") > Cc: Will Deacon <will@kernel.org> > Cc: Marc Zyngier <maz@kernel.org> > Cc: Oliver Upton <oliver.upton@linux.dev> > Cc: James Morse <james.morse@arm.com> > Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > Cc: Zenghui Yu <yuzenghui@huawei.com> > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
I really dislike the additional helper, but now that the capabilities are patched, I can't see another way to achieve this so:
Acked-by: Marc Zyngier <maz@kernel.org>
M.
-- Without deviation from the norm, progress is not possible.
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