From: Sudeep Holla sudeep.holla@arm.com
[ Upstream commit fa729bc7c9c8c17a2481358c841ef8ca920485d3 ]
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 Acked-by: Marc Zyngier maz@kernel.org Link: https://lore.kernel.org/r/20230704193243.3300506-1-sudeep.holla@arm.com Signed-off-by: Oliver Upton oliver.upton@linux.dev Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/include/asm/virt.h | 1 + arch/arm64/kvm/arm.c | 9 ++++++++- arch/arm64/kvm/pkvm.c | 2 +- 3 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index 4eb601e7de507..06382da630123 100644 --- a/arch/arm64/include/asm/virt.h +++ b/arch/arm64/include/asm/virt.h @@ -78,6 +78,7 @@ extern u32 __boot_cpu_mode[2];
void __hyp_set_vectors(phys_addr_t phys_vector_base); void __hyp_reset_vectors(void); +bool is_kvm_arm_initialised(void);
DECLARE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 7d8c3dd8b7ca9..3a2606ba3e583 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -51,11 +51,16 @@ DECLARE_KVM_HYP_PER_CPU(unsigned long, kvm_hyp_vector); DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page); DECLARE_KVM_NVHE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);
-static bool vgic_present; +static bool vgic_present, kvm_arm_initialised;
static DEFINE_PER_CPU(unsigned char, kvm_arm_hardware_enabled); DEFINE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
+bool is_kvm_arm_initialised(void) +{ + return kvm_arm_initialised; +} + int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) { return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE; @@ -2396,6 +2401,8 @@ static __init int kvm_arm_init(void) if (err) goto out_subs;
+ kvm_arm_initialised = true; + return 0;
out_subs: diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c index 6e9ece1ebbe72..3895416cb15ae 100644 --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c @@ -243,7 +243,7 @@ static int __init finalize_pkvm(void) { int ret;
- if (!is_protected_kvm_enabled()) + if (!is_protected_kvm_enabled() || !is_kvm_arm_initialised()) return 0;
/*