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vmm: Refactor amx tile state component enabling logic

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We enable AMX tile state components via the hypervisor (as introduced
in the previous commit) instead of doing this inline in the body of
`CpuManager::new`.

Signed-off-by: Oliver Anderson <oliver.anderson@cyberus-technology.de>
On-behalf-of: SAP oliver.anderson@sap.com
This commit is contained in:
Oliver Anderson 2025-12-04 12:51:46 +01:00 • committed by Rob Bradford
parent 01383538f3
commit 5ec1e66e22
1 changed files with 3 additions and 32 deletions
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35
vmm/src/cpu.rs
View file

@ -791,38 +791,9 @@ impl CpuManager {
#[cfg(target_arch = "x86_64")]
if config.features.amx {
const ARCH_GET_XCOMP_GUEST_PERM: usize = 0x1024;
const ARCH_REQ_XCOMP_GUEST_PERM: usize = 0x1025;
const XFEATURE_XTILEDATA: usize = 18;
const XFEATURE_XTILEDATA_MASK: usize = 1 << XFEATURE_XTILEDATA;
// SAFETY: the syscall is only modifying kernel internal
// data structures that the kernel is itself expected to safeguard.
let amx_tile = unsafe {
libc::syscall(
libc::SYS_arch_prctl,
ARCH_REQ_XCOMP_GUEST_PERM,
XFEATURE_XTILEDATA,
)
};
if amx_tile != 0 {
return Err(Error::AmxEnable(anyhow!("Guest AMX usage not supported")));
}
let mut mask: usize = 0;
// SAFETY: Syscall with valid parameters. We use a raw mutable pointer to
// the `mask` place in order to ensure that we do not violate Rust's
// aliasing rules.
let result = unsafe {
libc::syscall(
libc::SYS_arch_prctl,
ARCH_GET_XCOMP_GUEST_PERM,
&raw mut mask,
)
};
if result != 0 || (mask & XFEATURE_XTILEDATA_MASK) != XFEATURE_XTILEDATA_MASK {
return Err(Error::AmxEnable(anyhow!("Guest AMX usage not supported")));
}
hypervisor
.enable_amx_state_components()
.map_err(|e| Error::AmxEnable(e.into()))?;
}
let proximity_domain_per_cpu: BTreeMap<u32, u32> = {