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// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.
//! CPUID definitions.
use inspect::Inspect;
/// A CPUID result.
///
/// This may define a partial result if some mask bits are zero. This is used to
/// provide an update on top of another CPUID result provided elsewhere (e.g. by
/// the hypervisor).
#[derive(Debug, Copy, Clone)]
pub struct CpuidLeaf {
/// The CPUID function/leaf, provided in eax.
pub function: u32,
/// The CPUID index/subleaf, provided in ecx. If `None`, any index value is
/// accepted.
pub index: Option<u32>,
/// The result.
pub result: [u32; 4],
/// The bits of the result that are valid.
pub mask: [u32; 4],
}
impl CpuidLeaf {
/// Returns a new result for the given function.
pub fn new(function: u32, result: [u32; 4]) -> Self {
Self {
function,
index: None,
result,
mask: [!0; 4],
}
}
/// Updates the result to be for specific `index` and returns it.
pub fn indexed(self, index: u32) -> Self {
Self {
index: Some(index),
..self
}
}
/// Updates the result to be partial with the provided mask.
pub fn masked(self, mask: [u32; 4]) -> Self {
Self { mask, ..self }
}
fn cmp_key(&self, other: &Self) -> std::cmp::Ordering {
(self.function, self.index).cmp(&(other.function, other.index))
}
/// Returns true if this result is intended for the given `eax` and `ecx`
/// input values.
pub fn matches(&self, eax: u32, ecx: u32) -> bool {
self.function == eax && (self.index.is_none() || self.index == Some(ecx))
}
/// Applies this result to `result`, replacing bits in `result` with
/// `self.result` when the corresponding bits in `self.mask` are set.
pub fn apply(&self, result: &mut [u32; 4]) {
for ((x, y), m) in result.iter_mut().zip(self.result).zip(self.mask) {
*x &= !m;
*x |= y & m;
}
}
fn inspect_kv(&self) -> (String, impl '_ + Inspect) {
let key = if let Some(index) = self.index {
format!("{:#x}/{:#x}", self.function, index)
} else {
format!("{:#x}", self.function)
};
(
key,
inspect::adhoc(|req| {
let mut resp = req.respond();
resp.hex("eax", self.result[0])
.hex("ebx", self.result[1])
.hex("ecx", self.result[2])
.hex("edx", self.result[3]);
if self.mask != [!0, !0, !0, !0] {
resp.hex("eax_mask", self.mask[0])
.hex("ebx_mask", self.mask[1])
.hex("ecx_mask", self.mask[2])
.hex("edx_mask", self.mask[3]);
}
}),
)
}
}
/// A collection of CPUID results.
#[derive(Debug, Inspect)]
pub struct CpuidLeafSet {
#[inspect(
flatten,
with = "|x| inspect::iter_by_key(x.iter().map(|y| y.inspect_kv()))"
)]
leaves: Vec<CpuidLeaf>,
}
impl CpuidLeafSet {
/// Returns a new result set.
///
/// `leaves` may contain multiple results for the same function and index.
/// In this case, they are merged internally (respecting their mask bits),
/// with later leaves overriding earlier ones.
pub fn new(mut leaves: Vec<CpuidLeaf>) -> Self {
// Sort and combine entries. Note that this must be a stable sort to
// preserve ordering.
leaves.sort_by(|x, y| x.cmp_key(y));
leaves.dedup_by(|right, left| {
if left.cmp_key(right).is_ne() {
return false;
}
right.apply(&mut left.result);
for (x, y) in left.mask.iter_mut().zip(right.mask) {
*x |= y;
}
true
});
Self { leaves }
}
/// Extends this result collection with additional `leaves`, which are
/// merged as in [`new`](Self::new).
pub fn extend(&mut self, leaves: &[CpuidLeaf]) {
self.leaves.extend(leaves);
*self = Self::new(std::mem::take(&mut self.leaves));
}
/// Returns the merged leaves.
pub fn leaves(&self) -> &[CpuidLeaf] {
&self.leaves
}
/// Returns the result value to return for inputs `eax` and `ecx`.
///
/// `default` provides the base value which is used for a missing leaf or
/// for any bits of the result whose mask bits are clear.
pub fn result(&self, eax: u32, ecx: u32, default: &[u32; 4]) -> [u32; 4] {
let mut result = *default;
if let Some(x) = self.leaves.iter().find(|x| x.matches(eax, ecx)) {
x.apply(&mut result);
}
result
}
/// Updates an existing result to have the new value
/// Returns false if the leaf was not found
pub fn update_result(&mut self, eax: u32, ecx: u32, new_values: &[u32; 4]) -> bool {
if let Some(x) = self.leaves.iter_mut().find(|x| x.matches(eax, ecx)) {
x.result = *new_values;
return true;
}
false
}
}