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// Copyright 2025 The Axvisor Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use ax_errno::{AxResult, ax_err, ax_err_type};
use axhvc::{HyperCallCode, HyperCallResult};
use crate::{
GuestPhysAddr, MappingFlags,
runtime::{
VMRef,
ivc::{self, IVCChannel},
},
};
pub struct HyperCall {
vm: VMRef,
code: HyperCallCode,
args: [u64; 6],
}
impl HyperCall {
pub fn new(vm: VMRef, code: u64, args: [u64; 6]) -> AxResult<Self> {
let code = HyperCallCode::try_from(code as u32).map_err(|e| {
warn!("Invalid hypercall code: {code} e {e:?}");
ax_err_type!(InvalidInput)
})?;
Ok(Self { vm, code, args })
}
pub fn execute(&self) -> HyperCallResult {
match self.code {
HyperCallCode::HIVCPublishChannel => {
let key = self.args[0] as usize;
let shm_base_gpa_ptr = GuestPhysAddr::from_usize(self.args[1] as usize);
let shm_size_ptr = GuestPhysAddr::from_usize(self.args[2] as usize);
info!(
"VM[{}] HyperCall {:?} key {:#x}",
self.vm.id(),
self.code,
key
);
// User will pass the size of the shared memory region,
// we will allocate the shared memory region based on this size.
let shm_region_size = self.vm.read_from_guest_of::<usize>(shm_size_ptr)?;
ivc::ensure_channel_absent(self.vm.id(), key)?;
let requested_size = shm_region_size.min(ivc::MAX_IVC_CHANNEL_SIZE);
let (shm_base_gpa, shm_region_size) = self.vm.alloc_ivc_channel(requested_size)?;
let ivc_channel =
match IVCChannel::alloc(self.vm.id(), key, shm_region_size, shm_base_gpa) {
Ok(channel) => channel,
Err(err) => {
if let Err(release_err) =
self.vm.release_ivc_channel(shm_base_gpa, shm_region_size)
{
warn!(
"VM[{}] failed to release IVC GPA {shm_base_gpa:#x} after \
channel allocation failure: {release_err:?}",
self.vm.id()
);
}
return Err(err);
}
};
let actual_size = ivc_channel.size();
if let Err(err) = self.vm.map_region(
shm_base_gpa,
ivc_channel.base_hpa(),
actual_size,
MappingFlags::READ | MappingFlags::WRITE,
) {
if let Err(release_err) =
self.vm.release_ivc_channel(shm_base_gpa, shm_region_size)
{
warn!(
"VM[{}] failed to release IVC GPA {shm_base_gpa:#x} after mapping \
failure: {release_err:?}",
self.vm.id()
);
}
return Err(err);
}
if let Err(err) = self
.vm
.write_to_guest_of(shm_base_gpa_ptr, &shm_base_gpa.as_usize())
.and_then(|_| self.vm.write_to_guest_of(shm_size_ptr, &actual_size))
{
if let Err(unmap_err) = self.vm.unmap_region(shm_base_gpa, actual_size) {
warn!(
"VM[{}] failed to unmap IVC GPA {shm_base_gpa:#x} after guest write \
failure: {unmap_err:?}",
self.vm.id()
);
}
if let Err(release_err) =
self.vm.release_ivc_channel(shm_base_gpa, shm_region_size)
{
warn!(
"VM[{}] failed to release IVC GPA {shm_base_gpa:#x} after guest write \
failure: {release_err:?}",
self.vm.id()
);
}
return Err(err);
}
if let Err(err) = ivc::insert_channel(self.vm.id(), ivc_channel) {
if let Err(unmap_err) = self.vm.unmap_region(shm_base_gpa, actual_size) {
warn!(
"VM[{}] failed to unmap IVC GPA {shm_base_gpa:#x} after channel \
insert failure: {unmap_err:?}",
self.vm.id()
);
}
if let Err(release_err) =
self.vm.release_ivc_channel(shm_base_gpa, shm_region_size)
{
warn!(
"VM[{}] failed to release IVC GPA {shm_base_gpa:#x} after channel \
insert failure: {release_err:?}",
self.vm.id()
);
}
return Err(err);
}
Ok(0)
}
HyperCallCode::HIVCUnPublishChannel => {
let key = self.args[0] as usize;
info!(
"VM[{}] HyperCall {:?} with key {:#x}",
self.vm.id(),
self.code,
key
);
let (base_gpa, size) = ivc::unpublish_channel(self.vm.id(), key)?;
// The publisher's GPA mapping is always unmapped; subscribers keep their own
// GPA views. The shared HPA frame is freed when the last subscriber leaves.
self.vm.unmap_region(base_gpa, size)?;
self.vm.release_ivc_channel(base_gpa, size)?;
Ok(0)
}
HyperCallCode::HIVCSubscribChannel => {
let publisher_vm_id = self.args[0] as usize;
let key = self.args[1] as usize;
let shm_base_gpa_ptr = GuestPhysAddr::from_usize(self.args[2] as usize);
let shm_size_ptr = GuestPhysAddr::from_usize(self.args[3] as usize);
info!(
"VM[{}] HyperCall {:?} to VM[{}]",
self.vm.id(),
self.code,
publisher_vm_id
);
let shm_size = ivc::prepare_subscribe_channel(publisher_vm_id, key, self.vm.id())?;
let (shm_base_gpa, shm_region_size) = self.vm.alloc_ivc_channel(shm_size)?;
let subscribe_result = ivc::subscribe_to_channel_of_publisher(
publisher_vm_id,
key,
self.vm.id(),
shm_base_gpa,
);
let (base_hpa, actual_size) = match subscribe_result {
Ok(channel) => channel,
Err(err) => {
if let Err(release_err) =
self.vm.release_ivc_channel(shm_base_gpa, shm_region_size)
{
warn!(
"VM[{}] failed to release IVC GPA {shm_base_gpa:#x} after \
subscribe registration failure: {release_err:?}",
self.vm.id()
);
}
return Err(err);
}
};
// TODO: seperate the mapping flags of metadata and data.
if let Err(err) = self.vm.map_region(
shm_base_gpa,
base_hpa,
actual_size,
MappingFlags::READ | MappingFlags::WRITE,
) {
if let Err(unsub_err) = ivc::unsubscribe_from_channel_of_publisher(
publisher_vm_id,
key,
self.vm.id(),
) {
warn!(
"VM[{}] failed to rollback IVC subscription to VM[{}] key {key:#x} \
after mapping failure: {unsub_err:?}",
self.vm.id(),
publisher_vm_id
);
}
if let Err(release_err) =
self.vm.release_ivc_channel(shm_base_gpa, shm_region_size)
{
warn!(
"VM[{}] failed to release IVC GPA {shm_base_gpa:#x} after subscribe \
mapping failure: {release_err:?}",
self.vm.id()
);
}
return Err(err);
}
if let Err(err) = self
.vm
.write_to_guest_of(shm_base_gpa_ptr, &shm_base_gpa.as_usize())
.and_then(|_| self.vm.write_to_guest_of(shm_size_ptr, &actual_size))
{
if let Err(unmap_err) = self.vm.unmap_region(shm_base_gpa, actual_size) {
warn!(
"VM[{}] failed to unmap IVC GPA {shm_base_gpa:#x} after subscribe \
guest write failure: {unmap_err:?}",
self.vm.id()
);
}
if let Err(unsub_err) = ivc::unsubscribe_from_channel_of_publisher(
publisher_vm_id,
key,
self.vm.id(),
) {
warn!(
"VM[{}] failed to rollback IVC subscription to VM[{}] key {key:#x} \
after guest write failure: {unsub_err:?}",
self.vm.id(),
publisher_vm_id
);
}
if let Err(release_err) =
self.vm.release_ivc_channel(shm_base_gpa, shm_region_size)
{
warn!(
"VM[{}] failed to release IVC GPA {shm_base_gpa:#x} after subscribe \
guest write failure: {release_err:?}",
self.vm.id()
);
}
return Err(err);
}
info!(
"VM[{}] HyperCall HIVC_REGISTER_SUBSCRIBER success, base GPA: {:#x}, size: {}",
self.vm.id(),
shm_base_gpa,
actual_size
);
Ok(0)
}
HyperCallCode::HIVCUnSubscribChannel => {
let publisher_vm_id = self.args[0] as usize;
let key = self.args[1] as usize;
info!(
"VM[{}] HyperCall {:?} from VM[{}]",
self.vm.id(),
self.code,
publisher_vm_id
);
let (base_gpa, size) =
ivc::unsubscribe_from_channel_of_publisher(publisher_vm_id, key, self.vm.id())?;
self.vm.unmap_region(base_gpa, size)?;
self.vm.release_ivc_channel(base_gpa, size)?;
Ok(0)
}
_ => {
warn!("Unsupported hypercall code: {:?}", self.code);
ax_err!(Unsupported)?
}
}
}
}