From 4b1eded1f91812d576538f106b57352d25a6b484 Mon Sep 17 00:00:00 2001 From: Alexander Potapenko Date: Tue, 24 Sep 2024 15:23:14 +0200 Subject: executor: arm64: sys/linux: implement syz_kvm_setup_syzos_vm and syz_kvm_add_vcpu The old syz_kvm_setup_cpu() API mixed together VM and VCPU setup, making it harder to create and fuzz two VCPUs in the same VM. Introduce two new pseudo-syscalls, syz_kvm_setup_syzos_vm() and syz_kvm_add_vcpu(), that will simplify this task. syz_kvm_setup_syzos_vm() takes a VM file descriptor, performs VM setup (allocates guest memory and installs SYZOS code into it) and returns a new kvm_syz_vm resource, which is in fact a pointer to `struct kvm_syz_vm` encapsulating VM-specific data in the C code. syz_kvm_add_vcpu() takes the VM ID denoted by kvm_syz_vm and creates a new VCPU within that VM with a proper CPU number. It then stores the fuzzer-supplied SYZOS API sequence into the corresponding part (indexed by CPU number) of the VM memory slot, and sets up the CPU registers to interpret that sequence. The new pseudo-syscall let the fuzzer create independent CPUs that run different code sequences without interfering with each other. --- executor/common_kvm_arm64_syzos.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'executor/common_kvm_arm64_syzos.h') diff --git a/executor/common_kvm_arm64_syzos.h b/executor/common_kvm_arm64_syzos.h index ebfed175c..a22c0651c 100644 --- a/executor/common_kvm_arm64_syzos.h +++ b/executor/common_kvm_arm64_syzos.h @@ -79,7 +79,9 @@ typedef enum { // Main guest function that performs necessary setup and passes the control to the user-provided // payload. -GUEST_CODE static void guest_main(uint64 size, uint64 cpu) +__attribute__((used)) +GUEST_CODE static void +guest_main(uint64 size, uint64 cpu) { uint64 addr = ARM64_ADDR_USER_CODE + cpu * 0x1000; -- cgit mrf-deployment