diff options
| author | Alexander Potapenko <glider@google.com> | 2026-01-14 12:01:10 +0100 |
|---|---|---|
| committer | Alexander Potapenko <glider@google.com> | 2026-01-15 07:19:29 +0000 |
| commit | 3b7a3359989abfb9ee0c821fdc0a8be33f7e996d (patch) | |
| tree | eaaee157ddc8909a12b5c30edef7155913b615bb /sys | |
| parent | 0a1338c68f19bbea13b3ae7ce61a185b6a5f65ef (diff) | |
executor: sys/linux: SYZOS: add support for AMD Nested Event Injection
Implement SYZOS_API_NESTED_AMD_INJECT_EVENT to allow the L1 guest to
inject events (Interrupts, NMIs, Exceptions) into L2 via the VMCB EVENTINJ
field.
This primitive abstracts the VMCB bit-packing logic
(Vector, Type, Valid, Error Code) into a high-level API, enabling the fuzzer
to semantically mutate event injection parameters.
This targets KVM's nested event merging logic, specifically where L0 must
reconcile L1-injected events with Host-pending events.
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/linux/dev_kvm_amd64.txt | 9 | ||||
| -rw-r--r-- | sys/linux/test/amd64-syz_kvm_nested_amd_inject | 37 |
2 files changed, 46 insertions, 0 deletions
diff --git a/sys/linux/dev_kvm_amd64.txt b/sys/linux/dev_kvm_amd64.txt index ba5fa6e4c..7ac8028d9 100644 --- a/sys/linux/dev_kvm_amd64.txt +++ b/sys/linux/dev_kvm_amd64.txt @@ -152,6 +152,14 @@ syzos_api_nested_amd_invlpga { asid int64[0:65535] } +syzos_api_nested_amd_inject_event { + vm_id syzos_api_vm_id + vector int64[0:255] + type int64[0:7] + error_code int64 + flags int64[0:3] +} + # IDs here must match those in executor/common_kvm_amd64_syzos.h. syzos_api_call$x86 [ uexit syzos_api$x86[0, intptr] @@ -174,6 +182,7 @@ syzos_api_call$x86 [ nested_amd_invlpga syzos_api$x86[381, syzos_api_nested_amd_invlpga] nested_amd_stgi syzos_api$x86[382, void] nested_amd_clgi syzos_api$x86[383, void] + nested_amd_inject_event syzos_api$x86[384, syzos_api_nested_amd_inject_event] ] [varlen] kvm_text_x86 [ diff --git a/sys/linux/test/amd64-syz_kvm_nested_amd_inject b/sys/linux/test/amd64-syz_kvm_nested_amd_inject new file mode 100644 index 000000000..f41b89489 --- /dev/null +++ b/sys/linux/test/amd64-syz_kvm_nested_amd_inject @@ -0,0 +1,37 @@ +# +# requires: arch=amd64 -threaded +# +r0 = openat$kvm(0, &AUTO='/dev/kvm\x00', 0x0, 0x0) +r1 = ioctl$KVM_CREATE_VM(r0, AUTO, 0x0) +r2 = syz_kvm_setup_syzos_vm$x86(r1, &(0x7f0000c00000/0x400000)=nil) + +# Test AMD Nested Event Injection. +# +# 1. Setup nested environment (L1) and Create VM (L2). +# 2. Inject an NMI (Vector 2, Type 2, Valid) into L2 via VMCB EVENTINJ. +# 3. Launch L2. +# - This forces KVM L0 to parse EVENTINJ and handle the injection. +# - We expect L0 to succeed without crashing. +# +# Arguments for INJECT_EVENT: +# vm_id=0 +# vector=2 (NMI) +# type=2 (NMI) +# error_code=0 +# flags=1 (Valid=1, EV=0) +# +r3 = syz_kvm_add_vcpu$x86(r2, &AUTO={0x0, &AUTO=[@enable_nested={AUTO, AUTO, 0x0}, @nested_create_vm={AUTO, AUTO, 0x0}, @nested_amd_inject_event={AUTO, AUTO, {0x0, 0x2, 0x2, 0x0, 0x1}}, @nested_vmlaunch={AUTO, AUTO, 0x0}, @uexit={AUTO, AUTO, 0xface}], AUTO}) +r4 = ioctl$KVM_GET_VCPU_MMAP_SIZE(r0, AUTO) +r5 = mmap$KVM_VCPU(&(0x7f0000009000/0x1000)=nil, r4, 0x3, 0x1, r3, 0x0) + +# Run the VCPU. +# The guest executes the injection and launch. +# If KVM L0 processes the EVENTINJ correctly, the guest should eventually exit back to us. +# +ioctl$KVM_RUN(r3, AUTO, 0x0) +syz_kvm_assert_syzos_uexit$x86(r5, 0xface) + +# Cleanup +# +ioctl$KVM_RUN(r3, AUTO, 0x0) +syz_kvm_assert_syzos_uexit$x86(r5, 0xffffffff) |