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arch: aarch64: Remove hardcoded host IPA size

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With the ability of getting host IPA size in `hypervisor` crate,
we can query the host IPA size through ioctl instead of hardcoding
a maximum IPA size. Therefore this commit removes the hardcoded
maximum host IPA size.

Signed-off-by: Henry Wang <Henry.Wang@arm.com>
This commit is contained in:
Henry Wang 2021-06-09 20:45:11 +08:00 • committed by Sebastien Boeuf
parent 2fe3586eba
commit 1eb8a4671f
1 changed files with 12 additions and 16 deletions
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28
arch/src/aarch64/mod.rs
View file

@ -19,6 +19,7 @@ use crate::GuestMemoryMmap;
use crate::RegionType;
use gic::GicDevice;
use std::collections::HashMap;
use std::convert::TryInto;
use std::ffi::CStr;
use std::fmt::Debug;
use std::sync::Arc;
@ -195,22 +196,17 @@ fn get_fdt_addr() -> u64 {
}
pub fn get_host_cpu_phys_bits() -> u8 {
// The value returned here is used to determine the physical address space size
// for a VM (IPA size).
// In recent kernel versions, the maximum IPA size supported by the host can be
// known by querying cap KVM_CAP_ARM_VM_IPA_SIZE. And the IPA size for a
// guest can be configured smaller.
// But in Cloud-Hypervisor we simply use the maximum value for the VM.
// Reference https://lwn.net/Articles/766767/.
//
// The correct way to query KVM_CAP_ARM_VM_IPA_SIZE is via rust-vmm/kvm-ioctls,
// which wraps all IOCTL's and provides easy interface to user hypervisors.
// For now the cap hasn't been supported. A separate patch will be submitted to
// rust-vmm to add it.
// So a hardcoded value is used here as a temporary solution.
// It will be replace once rust-vmm/kvm-ioctls is ready.
//
40
// A dummy hypervisor created only for querying the host IPA size and will
// be freed after the query.
let hv = hypervisor::new().unwrap();
let host_cpu_phys_bits = hv.get_host_ipa_limit().try_into().unwrap();
if host_cpu_phys_bits == 0 {
// Host kernel does not support `get_host_ipa_limit`,
// we return the default value 40 here.
40
} else {
host_cpu_phys_bits
}
}
#[cfg(test)]