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 <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Oliver Upton <[email protected]>
Cc: James Morse <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Cc: Zenghui Yu <[email protected]>
Signed-off-by: Sudeep Holla <[email protected]>
---
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 5227db7640c8..261d6e9df2e1 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 173abca08b53..4e0176b44af3 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -53,11 +53,16 @@ DECLARE_KVM_NVHE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);
DECLARE_KVM_NVHE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
-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;
@@ -2484,6 +2489,8 @@ 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 994a494703c3..6ff3ec18c925 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -244,7 +244,7 @@ static int __init finalize_pkvm(void)
{
int ret;
- if (!is_protected_kvm_enabled())
+ if (!is_protected_kvm_enabled() || !is_kvm_arm_initialised())
return 0;
/*
--
2.41.0
On Tue, 04 Jul 2023 20:32:43 +0100,
Sudeep Holla <[email protected]> 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 <[email protected]>
> Cc: Marc Zyngier <[email protected]>
> Cc: Oliver Upton <[email protected]>
> Cc: James Morse <[email protected]>
> Cc: Suzuki K Poulose <[email protected]>
> Cc: Zenghui Yu <[email protected]>
> Signed-off-by: Sudeep Holla <[email protected]>
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 <[email protected]>
M.
--
Without deviation from the norm, progress is not possible.
On Tue, Jul 11, 2023 at 09:36:46AM +0100, Marc Zyngier wrote:
> On Tue, 04 Jul 2023 20:32:43 +0100,
> Sudeep Holla <[email protected]> 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 <[email protected]>
> > Cc: Marc Zyngier <[email protected]>
> > Cc: Oliver Upton <[email protected]>
> > Cc: James Morse <[email protected]>
> > Cc: Suzuki K Poulose <[email protected]>
> > Cc: Zenghui Yu <[email protected]>
> > Signed-off-by: Sudeep Holla <[email protected]>
>
> I really dislike the additional helper, but now that the capabilities
> are patched, I can't see another way to achieve this so:
>
Yes, I too don't like it and was almost tempted to post it as RFC, but then
I didn't want it to get ignored ;) as it a bug I hit on my setup with
mismatched FF-A version.
> Acked-by: Marc Zyngier <[email protected]>
>
Thanks!
--
Regards,
Sudeep
On Tue, 4 Jul 2023 20:32:43 +0100, Sudeep Holla 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 ]---
>
> [...]
Applied to kvmarm/fixes, thanks!
[1/1] KVM: arm64: Handle kvm_arm_init failure correctly in finalize_pkvm
https://git.kernel.org/kvmarm/kvmarm/c/fa729bc7c9c8
--
Best,
Oliver