// Copyright 2020 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.

// This file is shared between executor and csource package.

// Implementation of syz_kvm_setup_cpu pseudo-syscall.
// See Intel Software Developer’s Manual Volume 3: System Programming Guide
// for details on what happens here.

#include "kvm.h"

struct kvm_text {
	uintptr_t typ;
	const void* text;
	uintptr_t size;
};

// syz_kvm_setup_cpu(fd fd_kvmvm, cpufd fd_kvmcpu, usermem vma[24], text ptr[in, array[kvm_text, 1]], ntext len[text], flags flags[kvm_setup_flags], opts ptr[in, array[kvm_setup_opt, 0:2]], nopt len[opts])
static long syz_kvm_setup_cpu(volatile long a0, volatile long a1, volatile long a2, volatile long a3, volatile long a4, volatile long a5, volatile long a6, volatile long a7)
{
	const int vmfd = a0;
	const int cpufd = a1;
	char* const host_mem = (char*)a2;
	const struct kvm_text* const text_array_ptr = (struct kvm_text*)a3;
	const uintptr_t text_count = a4;

	const uintptr_t page_size = 16 << 10;
	const uintptr_t guest_mem_size = 256 << 20;
	const uintptr_t guest_mem = 0;

	(void)text_count; // fuzzer can spoof count and we need just 1 text, so ignore text_count
	const void* text = 0;
	uintptr_t text_size = 0;
	NONFAILING(text = text_array_ptr[0].text);
	NONFAILING(text_size = text_array_ptr[0].size);

	for (uintptr_t i = 0; i < guest_mem_size / page_size; i++) {
		struct kvm_userspace_memory_region memreg;
		memreg.slot = i;
		memreg.flags = 0; // can be KVM_MEM_LOG_DIRTY_PAGES | KVM_MEM_READONLY
		memreg.guest_phys_addr = guest_mem + i * page_size;
		memreg.memory_size = page_size;
		memreg.userspace_addr = (uintptr_t)host_mem + i * page_size;
		ioctl(vmfd, KVM_SET_USER_MEMORY_REGION, &memreg);
	}

	struct kvm_regs regs;
	struct kvm_sregs sregs;
	if (ioctl(cpufd, KVM_GET_SREGS, &sregs))
		return -1;
	if (ioctl(cpufd, KVM_GET_REGS, &regs))
		return -1;

	// PPC64LE, real mode: MSR_LE | MSR_SF
	regs.msr = 1ULL | (1ULL << 63);

	memcpy(host_mem, text, text_size);

	if (ioctl(cpufd, KVM_SET_SREGS, &sregs))
		return -1;
	if (ioctl(cpufd, KVM_SET_REGS, &regs))
		return -1;

		// Hypercalls need to be enable so we enable them all here to
		// allow fuzzing
#define MAX_HCALL 0x450
	for (unsigned hcall = 4; hcall < MAX_HCALL; hcall += 4) {
		struct kvm_enable_cap cap = {
		    .cap = KVM_CAP_PPC_ENABLE_HCALL,
		    .flags = 0,
		    .args = {hcall, 1},
		};
		ioctl(vmfd, KVM_ENABLE_CAP, &cap);
	}

	return 0;
}