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-rw-r--r--sys/linux/dev_kvm_amd64.txt8
-rw-r--r--sys/linux/test/amd64-syz_kvm_nested_amd_set_intercept39
2 files changed, 47 insertions, 0 deletions
diff --git a/sys/linux/dev_kvm_amd64.txt b/sys/linux/dev_kvm_amd64.txt
index acd80540c..0d90ceeab 100644
--- a/sys/linux/dev_kvm_amd64.txt
+++ b/sys/linux/dev_kvm_amd64.txt
@@ -160,6 +160,13 @@ syzos_api_nested_amd_inject_event {
flags int64[0:3]
}
+syzos_api_nested_amd_set_intercept {
+ vm_id syzos_api_vm_id
+ offset int64
+ bit_mask int64
+ action int64[0:1]
+}
+
# IDs here must match those in executor/common_kvm_amd64_syzos.h.
syzos_api_call$x86 [
uexit syzos_api$x86[0, intptr]
@@ -183,6 +190,7 @@ syzos_api_call$x86 [
nested_amd_stgi syzos_api$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]
+ nested_amd_set_intercept syzos_api$x86[385, syzos_api_nested_amd_set_intercept]
] [varlen]
kvm_text_x86 [
diff --git a/sys/linux/test/amd64-syz_kvm_nested_amd_set_intercept b/sys/linux/test/amd64-syz_kvm_nested_amd_set_intercept
new file mode 100644
index 000000000..91293ba0d
--- /dev/null
+++ b/sys/linux/test/amd64-syz_kvm_nested_amd_set_intercept
@@ -0,0 +1,39 @@
+#
+# requires: arch=amd64 -threaded
+#
+r0 = openat$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 Intercepts: The RDTSC Liberation
+#
+# 1. L1 Setup:
+# - SYZOS initializes VMCB with ALL intercepts enabled.
+# - We call SET_INTERCEPT to *CLEAR* the RDTSC intercept.
+# - Offset: 0xC (Control Vector 1)
+# - Bit: 14 (0x4000) = RDTSC
+# - Action: 0 (Clear/Disable)
+#
+# 2. L2 Payload:
+# - "rdtsc" (0x0f 0x31)
+# - "hlt" (0xf4)
+#
+# 3. Execution Flow:
+# - If RDTSC is intercepted: Exit Reason = RDTSC (0x4).
+# - If RDTSC is native: executes RDTSC -> executes HLT -> Exit Reason = HLT (0x1).
+#
+r3 = syz_kvm_add_vcpu$x86(r2, &AUTO={0x0, &AUTO=[@enable_nested={AUTO, AUTO, 0x0}, @nested_create_vm={AUTO, AUTO, 0x0}, @nested_amd_set_intercept={AUTO, AUTO, {0x0, 0xC, 0x4000, 0x0}}, @nested_load_code={AUTO, AUTO, {0x0, "0f31f4"}}, @nested_vmlaunch={AUTO, AUTO, 0x0}], AUTO})
+r4 = ioctl$KVM_GET_VCPU_MMAP_SIZE(r0, AUTO)
+r5 = mmap$KVM_VCPU(&(0x7f0000009000/0x1000)=nil, r4, 0x3, 0x1, r3, 0x0)
+
+# Run the VCPU.
+# Expectation: Success (Native Execution) -> HLT Exit.
+# Code: 0xe2e20001 (SYZOS_NESTED_EXIT_REASON_HLT)
+#
+ioctl$KVM_RUN(r3, AUTO, 0x0)
+syz_kvm_assert_syzos_uexit$x86(r3, r5, 0xe2e20001)
+
+# Cleanup
+#
+ioctl$KVM_RUN(r3, AUTO, 0x0)
+syz_kvm_assert_syzos_uexit$x86(r3, r5, 0xffffffffffffffff)