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// Copyright 2024 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.
// Generate KVM ARM64 register IDs for dev_kvm.txt
// Usage:
//
// go run registers.go msr_mrs.txt
package main
import (
"bytes"
"fmt"
"os"
"regexp"
"strconv"
"strings"
"github.com/google/syzkaller/pkg/tool"
)
func main() {
if len(os.Args) != 2 {
tool.Failf("usage: gen msr_mrs.txt")
}
input, err := os.ReadFile(os.Args[1])
if err != nil {
tool.Failf("failed to open input file: %v", err)
}
fmt.Printf("# Register descriptions generated by tools/arm64/registers.go\n")
printSysRegIDs(input)
printCoreRegs()
fmt.Printf("# End of register descriptions generated by tools/arm64/registers.go\n")
}
// Process input lines and return a string containing the list of corresponding register IDs.
func printSysRegIDs(table []byte) {
ret := ""
for _, line := range bytes.Split(table, []byte("\n")) {
if bytes.HasPrefix(line, []byte("#")) {
continue
}
lineStr := strings.TrimSpace(string(line))
if lineStr == "" {
continue
}
expandedLines := expandLine(lineStr)
for _, eline := range expandedLines {
value, err := processLine(eline)
if err == nil {
if ret != "" {
ret += ", "
}
ret += fmt.Sprintf("0x%x", value)
} else {
fmt.Fprintf(os.Stdout, "%v\n", err)
}
}
}
fmt.Printf("kvm_regs_arm64_sys = %s\n", ret)
}
// Process a single line of the following form:
//
// `0b10 0b000 0b0000 0b0010 0b000 MDCCINT_EL1 ...`
//
// or
//
// `0b00 0b000 0b0100 - 0b101 SPSel ...`
//
// - extract five operands from it (treat "-" as a zero) and generate a register ID from them.
func processLine(line string) (int64, error) {
fields := strings.Fields(line)
if len(fields) < 6 {
return 0, fmt.Errorf("line has too few fields: %s", line)
}
var operands []int
for i := 0; i < 5; i++ {
if fields[i] != "-" {
val, err := strconv.ParseInt(strings.TrimPrefix(fields[i], "0b"), 2, 64)
if err != nil {
return 0, fmt.Errorf("conversion error: %w", err)
}
operands = append(operands, int(val))
} else {
operands = append(operands, 0)
}
}
id := arm64KVMRegID(operands)
return id, nil
}
// If a line contains bit wildcards, replace them with all possible bit permutations.
//
// E.g. the following line:
//
// `0b11 0b100 0b1100 0b1000 0b0:n[1:0] ICH_AP0R<n>_EL2 ...`
//
// will be expanded to:
//
// `0b11 0b100 0b1100 0b1000 0b000 ICH_AP0R<n>_EL2 ...`
// `0b11 0b100 0b1100 0b1000 0b001 ICH_AP0R<n>_EL2 ...`
// `0b11 0b100 0b1100 0b1000 0b010 ICH_AP0R<n>_EL2 ...`
// `0b11 0b100 0b1100 0b1000 0b011 ICH_AP0R<n>_EL2 ...`
func expandLine(line string) []string {
re := regexp.MustCompile(`(:)?n\[(\d+)(:(\d+))?\]`)
match := re.FindStringSubmatch(line)
if match == nil {
return []string{line}
}
prefix := "0b"
// If n[] is preceded by ":", there is a 0b prefix in front of it already.
if match[1] == ":" {
prefix = ""
}
start, _ := strconv.Atoi(match[2])
end := start
if match[3] != "" {
end, _ = strconv.Atoi(match[4])
}
m := start - end + 1
numPermutations := 1 << m
expandedLines := make([]string, 0, numPermutations)
for i := 0; i < numPermutations; i++ {
bits := fmt.Sprintf("%s%0*b", prefix, m, i)
newLine := strings.Replace(line, match[0], bits, 1)
if strings.Contains(newLine, "n[") {
secondary := expandLine(newLine)
expandedLines = append(expandedLines, secondary...)
} else {
expandedLines = append(expandedLines, newLine)
}
}
return expandedLines
}
const (
// Constants from https://elixir.bootlin.com/linux/v6.10.2/source/arch/arm64/include/uapi/asm/kvm.h
kvmRegArmCoprocShift = 16
kvmRegArm64Sysreg int64 = (0x0013 << kvmRegArmCoprocShift)
kvmRegSizeU64 int64 = 0x0030000000000000
kvmRegArm64 int64 = 0x6000000000000000
)
// Generate register ID from Op0, Op1, CRn, CRm, Op2.
// See https://elixir.bootlin.com/linux/v6.10.2/source/arch/arm64/include/uapi/asm/kvm.h#L257 for more details.
func arm64KVMRegID(operands []int) int64 {
shifts := [5]int64{14, 11, 7, 3, 0}
ret := kvmRegSizeU64 | kvmRegArm64 | kvmRegArm64Sysreg
for i := 0; i < 5; i++ {
ret |= (int64(operands[i]) << shifts[i])
}
return ret
}
// Generate core register IDs.
// See https://docs.kernel.org/virt/kvm/api.html for more details.
func printCoreRegs() {
fmt.Printf("# Extra registers that KVM_GET_REG_LIST prints on QEMU\n")
// Some of these register IDs do not have corresponding registers, yet the kernel returns them.
// TODO(glider): figure out why this is happening.
fmt.Printf("kvm_regs_arm64_extra = 0x603000000013c01b, 0x603000000013c01f, 0x603000000013c022, 0x603000000013c023, " +
"0x603000000013c025, 0x603000000013c026, 0x603000000013c027, 0x603000000013c02a, 0x603000000013c02b, " +
"0x603000000013c02e, 0x603000000013c02f, 0x603000000013c033, 0x603000000013c034, 0x603000000013c035, " +
"0x603000000013c036, 0x603000000013c037, 0x603000000013c03b, 0x603000000013c03c, 0x603000000013c03d, " +
"0x603000000013c03e, 0x603000000013c03f, 0x603000000013c103, 0x603000000013c512, 0x603000000013c513\n")
}
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