linux_dsm_epyc7002/arch/arm64
James Morse 7d82602909 KVM: arm64: Forbid kprobing of the VHE world-switch code
On systems with VHE the kernel and KVM's world-switch code run at the
same exception level. Code that is only used on a VHE system does not
need to be annotated as __hyp_text as it can reside anywhere in the
kernel text.

__hyp_text was also used to prevent kprobes from patching breakpoint
instructions into this region, as this code runs at a different
exception level. While this is no longer true with VHE, KVM still
switches VBAR_EL1, meaning a kprobe's breakpoint executed in the
world-switch code will cause a hyp-panic.

echo "p:weasel sysreg_save_guest_state_vhe" > /sys/kernel/debug/tracing/kprobe_events
echo 1 > /sys/kernel/debug/tracing/events/kprobes/weasel/enable
lkvm run -k /boot/Image --console serial -p "console=ttyS0 earlycon=uart,mmio,0x3f8"

  # lkvm run -k /boot/Image -m 384 -c 3 --name guest-1474
  Info: Placing fdt at 0x8fe00000 - 0x8fffffff
  Info: virtio-mmio.devices=0x200@0x10000:36

  Info: virtio-mmio.devices=0x200@0x10200:37

  Info: virtio-mmio.devices=0x200@0x10400:38

[  614.178186] Kernel panic - not syncing: HYP panic:
[  614.178186] PS:404003c9 PC:ffff0000100d70e0 ESR:f2000004
[  614.178186] FAR:0000000080080000 HPFAR:0000000000800800 PAR:1d00007edbadc0de
[  614.178186] VCPU:00000000f8de32f1
[  614.178383] CPU: 2 PID: 1482 Comm: kvm-vcpu-0 Not tainted 5.0.0-rc2 #10799
[  614.178446] Call trace:
[  614.178480]  dump_backtrace+0x0/0x148
[  614.178567]  show_stack+0x24/0x30
[  614.178658]  dump_stack+0x90/0xb4
[  614.178710]  panic+0x13c/0x2d8
[  614.178793]  hyp_panic+0xac/0xd8
[  614.178880]  kvm_vcpu_run_vhe+0x9c/0xe0
[  614.178958]  kvm_arch_vcpu_ioctl_run+0x454/0x798
[  614.179038]  kvm_vcpu_ioctl+0x360/0x898
[  614.179087]  do_vfs_ioctl+0xc4/0x858
[  614.179174]  ksys_ioctl+0x84/0xb8
[  614.179261]  __arm64_sys_ioctl+0x28/0x38
[  614.179348]  el0_svc_common+0x94/0x108
[  614.179401]  el0_svc_handler+0x38/0x78
[  614.179487]  el0_svc+0x8/0xc
[  614.179558] SMP: stopping secondary CPUs
[  614.179661] Kernel Offset: disabled
[  614.179695] CPU features: 0x003,2a80aa38
[  614.179758] Memory Limit: none
[  614.179858] ---[ end Kernel panic - not syncing: HYP panic:
[  614.179858] PS:404003c9 PC:ffff0000100d70e0 ESR:f2000004
[  614.179858] FAR:0000000080080000 HPFAR:0000000000800800 PAR:1d00007edbadc0de
[  614.179858] VCPU:00000000f8de32f1 ]---

Annotate the VHE world-switch functions that aren't marked
__hyp_text using NOKPROBE_SYMBOL().

Signed-off-by: James Morse <james.morse@arm.com>
Fixes: 3f5c90b890 ("KVM: arm64: Introduce VHE-specific kvm_vcpu_run")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-02-07 11:44:47 +00:00
..
boot arm64: dts: marvell: mcbin: fix PCIe reset signal 2019-01-10 12:20:32 +01:00
configs arm64: defconfig: enable modules for amlogic s400 sound card 2019-01-08 15:27:50 -08:00
crypto Kbuild updates for v4.21 2018-12-29 12:03:17 -08:00
include arm/arm64: KVM: Allow a VCPU to fully reset itself 2019-02-07 11:44:13 +00:00
kernel arm64: kaslr: ensure randomized quantities are clean to the PoC 2019-01-16 12:00:46 +00:00
kvm KVM: arm64: Forbid kprobing of the VHE world-switch code 2019-02-07 11:44:47 +00:00
lib arm64: string: use asm EXPORT_SYMBOL() 2018-12-10 11:50:12 +00:00
mm arm64 fixes for -rc1 2019-01-05 11:28:39 -08:00
net bpf: arm64: Enable arm64 jit to provide bpf_line_info 2018-12-12 02:16:56 +01:00
xen arm64: mm: Add additional parameter to uaccess_ttbr0_disable 2018-01-17 13:57:49 +01:00
Kconfig Kconfig file consolidation for v4.21 2018-12-29 13:40:29 -08:00
Kconfig.debug Kconfig: consolidate the "Kernel hacking" menu 2018-08-02 08:06:48 +09:00
Kconfig.platforms ARM: SoC: late updates 2019-01-05 11:30:37 -08:00
Makefile kasan, arm64: adjust shadow size for tag-based mode 2018-12-28 12:11:43 -08:00