use std::convert::Infallible;
use std::convert::TryInto;
use std::error::Error;
use std::io::Error as IoError;
use std::io::ErrorKind;
use std::mem;
use std::num::TryFromIntError;
use libc::{PROT_READ, PROT_WRITE};
use nix::poll::PollFlags;
use nix::poll::{poll, PollFd};
use xenctrl::consts::{PAGE_SHIFT, PAGE_SIZE};
use xenctrl::error::XcError;
use xenctrl::RING_HAS_UNCONSUMED_REQUESTS;
use xenctrl::{XenControl, XenCr, XenEventType};
use xenevtchn::XenEventChannel;
use xenforeignmemory::{XenForeignMem, XenForeignMemoryError};
use xenstore_rs::{XBTransaction, Xs, XsOpenFlags};
use xenvmevent_sys::{
vm_event_back_ring, vm_event_response_t, VM_EVENT_FLAG_VCPU_PAUSED, VM_EVENT_INTERFACE_VERSION,
};
use crate::api::events::{CrType, Event, EventType, InterceptType};
use crate::api::params::DriverInitParams;
use crate::api::registers::{Registers, SegmentReg, SystemTableReg, X86Registers};
use crate::api::{DriverType, Introspectable};
#[derive(Debug)]
pub struct Xen {
xc: XenControl,
xev: XenEventChannel,
xen_fgn: XenForeignMem,
_dom_name: String,
domid: u32,
back_ring: vm_event_back_ring,
}
#[derive(thiserror::Error, Debug)]
pub enum XenDriverError {
#[error("Xen driver requires a VM name parameter")]
MissingVMName,
#[error("failed to read xenstore entry {0}: {1}")]
XenstoreReadError(String, IoError),
#[error("domain {0} not found in xenstore")]
XenstoreDomainNotFoundError(String),
#[error("event version mismatch: {0} <-> {1}")]
EventVersionMismatch(u32, u32),
#[error("failed to convert integer")]
TryFromIntError(#[from] TryFromIntError),
#[error("failed to convert integer")]
InfallibleFromIntError(#[from] Infallible),
#[error("IO error")]
IoError(#[from] IoError),
#[error("xenctrl error")]
XcError(#[from] XcError),
#[error("UNIX error")]
NixError(#[from] nix::Error),
#[error("xenforeignmemory error")]
ForeignMemoryError(#[from] XenForeignMemoryError),
}
impl Xen {
pub fn new(init_params: DriverInitParams) -> Result<Self, Box<dyn Error>> {
let domain_name = init_params
.common
.ok_or(XenDriverError::MissingVMName)?
.vm_name;
let xs = Xs::new(XsOpenFlags::ReadOnly)?;
let mut found: bool = false;
let mut cand_domid = 0;
for domid_str in xs.directory(XBTransaction::Null, "/local/domain")? {
let name_path = format!("/local/domain/{}/name", domid_str);
let candidate = match xs.read(XBTransaction::Null, &name_path) {
Ok(candidate) => candidate,
Err(error) => {
match error.kind() {
ErrorKind::PermissionDenied => {
debug!("failed to read xenstore entry {}", name_path);
continue;
}
_ => {
return Err(Box::new(XenDriverError::XenstoreReadError(
name_path, error,
)))
}
}
}
};
debug!("Xenstore entry: [{}] {}", domid_str, candidate);
if candidate == *domain_name {
cand_domid = domid_str.parse::<u32>().unwrap();
found = true;
}
}
if !found {
return Err(Box::new(XenDriverError::XenstoreDomainNotFoundError(
domain_name,
)));
}
let mut xc = XenControl::new(None, None, 0)?;
let (_ring_page, back_ring, remote_port) = xc.monitor_enable(cand_domid)?;
let xev = XenEventChannel::new(cand_domid, remote_port)?;
let xen_fgn = XenForeignMem::new()?;
let xen = Xen {
xc,
xev,
xen_fgn,
_dom_name: domain_name,
domid: cand_domid,
back_ring,
};
trace!("Initialized {:#?}", xen);
Ok(xen)
}
}
impl Introspectable for Xen {
fn read_physical(
&self,
paddr: u64,
buf: &mut [u8],
bytes_read: &mut u64,
) -> Result<(), Box<dyn Error>> {
let mut cur_paddr: u64;
let mut count_mut: u64 = buf.len() as u64;
let mut buf_offset: u64 = 0;
*bytes_read = 0;
while count_mut > 0 {
cur_paddr = paddr + buf_offset;
let gfn = cur_paddr >> PAGE_SHIFT;
let page_offset = u64::from(PAGE_SIZE - 1) & cur_paddr;
let page = self
.xen_fgn
.map(self.domid, PROT_READ, gfn)
.map_err(XenDriverError::from)?;
let read_len = if (page_offset + count_mut) > u64::from(PAGE_SIZE) {
u64::from(PAGE_SIZE) - page_offset
} else {
count_mut
};
let buf_start = buf_offset as usize;
let buf_end = (buf_offset + read_len) as usize;
let page_start = page_offset as usize;
let page_end = (page_offset + read_len) as usize;
buf[buf_start..buf_end].copy_from_slice(&page[page_start..page_end]);
count_mut -= read_len;
buf_offset += read_len;
*bytes_read += read_len;
self.xen_fgn.unmap(page).map_err(XenDriverError::from)?;
}
Ok(())
}
fn write_physical(&self, paddr: u64, buf: &[u8]) -> Result<(), Box<dyn Error>> {
let mut phys_address: u64;
let mut offset: u64;
let mut count_mut: u64 = buf.len() as u64;
let mut buf_offset: u64 = 0;
while count_mut > 0 {
phys_address = paddr + buf_offset;
let pfn = phys_address >> PAGE_SHIFT;
offset = u64::from(PAGE_SIZE - 1) & phys_address;
let page = self
.xen_fgn
.map(self.domid, PROT_WRITE, pfn)
.map_err(XenDriverError::from)?;
let write_len = if (offset + count_mut) > u64::from(PAGE_SIZE) {
u64::from(PAGE_SIZE) - offset
} else {
count_mut
};
page[offset as usize..write_len as usize].copy_from_slice(&buf[buf_offset as usize..]);
count_mut -= write_len;
buf_offset += write_len;
self.xen_fgn.unmap(page).map_err(XenDriverError::from)?;
}
Ok(())
}
fn get_max_physical_addr(&self) -> Result<u64, Box<dyn Error>> {
let max_gpfn = self
.xc
.domain_maximum_gpfn(self.domid)
.map_err(XenDriverError::from)?;
Ok(max_gpfn << PAGE_SHIFT)
}
fn get_vcpu_count(&self) -> Result<u16, Box<dyn Error>> {
let domain_info = self
.xc
.domain_getinfolist(self.domid)
.map_err(XenDriverError::from)?
.ok_or("Domain info not found")?;
Ok((domain_info.max_vcpu_id + 1).try_into().unwrap())
}
fn read_registers(&self, vcpu: u16) -> Result<Registers, Box<dyn Error>> {
let hvm_cpu = self
.xc
.domain_hvm_getcontext_partial(self.domid, vcpu)
.map_err(XenDriverError::from)?;
Ok(Registers::X86(X86Registers {
rax: hvm_cpu.rax,
rbx: hvm_cpu.rbx,
rcx: hvm_cpu.rcx,
rdx: hvm_cpu.rdx,
rsi: hvm_cpu.rsi,
rdi: hvm_cpu.rdi,
rsp: hvm_cpu.rsp,
rbp: hvm_cpu.rbp,
r8: hvm_cpu.r8,
r9: hvm_cpu.r9,
r10: hvm_cpu.r10,
r11: hvm_cpu.r11,
r12: hvm_cpu.r12,
r13: hvm_cpu.r13,
r14: hvm_cpu.r14,
r15: hvm_cpu.r15,
rip: hvm_cpu.rip,
rflags: hvm_cpu.rflags,
cr0: hvm_cpu.cr0,
cr3: hvm_cpu.cr3,
cr4: hvm_cpu.cr4,
cr2: hvm_cpu.cr2,
sysenter_cs: hvm_cpu.sysenter_cs,
sysenter_esp: hvm_cpu.sysenter_esp,
sysenter_eip: hvm_cpu.sysenter_eip,
msr_efer: hvm_cpu.msr_efer,
msr_star: hvm_cpu.msr_star,
msr_lstar: hvm_cpu.msr_lstar,
cs: SegmentReg {
base: hvm_cpu.cs_base,
limit: hvm_cpu.cs_limit,
selector: hvm_cpu.cs_sel.try_into().map_err(XenDriverError::from)?,
},
ds: SegmentReg {
base: hvm_cpu.ds_base,
limit: hvm_cpu.ds_limit,
selector: hvm_cpu.ds_sel.try_into().map_err(XenDriverError::from)?,
},
es: SegmentReg {
base: hvm_cpu.es_base,
limit: hvm_cpu.es_limit,
selector: hvm_cpu.es_sel.try_into().map_err(XenDriverError::from)?,
},
fs: SegmentReg {
base: hvm_cpu.fs_base,
limit: hvm_cpu.fs_limit,
selector: hvm_cpu.fs_sel.try_into().map_err(XenDriverError::from)?,
},
gs: SegmentReg {
base: hvm_cpu.gs_base,
limit: hvm_cpu.gs_limit,
selector: hvm_cpu.gs_sel.try_into().map_err(XenDriverError::from)?,
},
ss: SegmentReg {
base: hvm_cpu.ss_base,
limit: hvm_cpu.ss_limit,
selector: hvm_cpu.ss_sel.try_into().map_err(XenDriverError::from)?,
},
tr: SegmentReg {
base: hvm_cpu.tr_base,
limit: hvm_cpu.tr_limit,
selector: hvm_cpu.tr_sel.try_into().map_err(XenDriverError::from)?,
},
idt: SystemTableReg {
base: hvm_cpu.idtr_base,
limit: hvm_cpu.idtr_limit as u16,
},
gdt: SystemTableReg {
base: hvm_cpu.gdtr_base,
limit: hvm_cpu.gdtr_limit as u16,
},
..Default::default()
}))
}
fn write_registers(&self, vcpu: u16, reg: Registers) -> Result<(), Box<dyn Error>> {
let (buffer, mut cpu, size) = self.xc.domain_hvm_getcontext(self.domid, vcpu)?;
match reg {
Registers::X86(x86_registers) => {
cpu.rax = x86_registers.rax;
cpu.rbx = x86_registers.rbx;
cpu.rcx = x86_registers.rcx;
cpu.rdx = x86_registers.rdx;
cpu.rsi = x86_registers.rsi;
cpu.rdi = x86_registers.rdi;
cpu.rsp = x86_registers.rsp;
cpu.rbp = x86_registers.rbp;
cpu.r8 = x86_registers.r8;
cpu.r9 = x86_registers.r9;
cpu.r10 = x86_registers.r10;
cpu.r11 = x86_registers.r11;
cpu.r12 = x86_registers.r12;
cpu.r13 = x86_registers.r13;
cpu.r14 = x86_registers.r14;
cpu.r15 = x86_registers.r15;
cpu.rip = x86_registers.rip;
cpu.rflags = x86_registers.rflags;
cpu.cr0 = x86_registers.cr0;
cpu.cr2 = x86_registers.cr2;
cpu.cr3 = x86_registers.cr3;
cpu.cr4 = x86_registers.cr4;
cpu.sysenter_cs = x86_registers.sysenter_cs;
cpu.sysenter_esp = x86_registers.sysenter_esp;
cpu.sysenter_eip = x86_registers.sysenter_eip;
cpu.msr_star = x86_registers.msr_star;
cpu.msr_lstar = x86_registers.msr_lstar;
cpu.msr_efer = x86_registers.msr_efer;
cpu.cs_base = x86_registers.cs.base;
cpu.ds_base = x86_registers.ds.base;
cpu.es_base = x86_registers.es.base;
cpu.fs_base = x86_registers.fs.base;
cpu.gs_base = x86_registers.gs.base;
cpu.ss_base = x86_registers.ss.base;
cpu.tr_base = x86_registers.tr.base;
cpu.cs_limit = x86_registers.cs.limit;
cpu.ds_limit = x86_registers.ds.limit;
cpu.es_limit = x86_registers.es.limit;
cpu.fs_limit = x86_registers.fs.limit;
cpu.gs_limit = x86_registers.gs.limit;
cpu.ss_limit = x86_registers.ss.limit;
cpu.tr_limit = x86_registers.tr.limit;
cpu.cs_sel = x86_registers.cs.selector.into();
cpu.ds_sel = x86_registers.ds.selector.into();
cpu.es_sel = x86_registers.es.selector.into();
cpu.fs_sel = x86_registers.fs.selector.into();
cpu.gs_sel = x86_registers.gs.selector.into();
cpu.ss_sel = x86_registers.ss.selector.into();
cpu.tr_sel = x86_registers.tr.selector.into();
}
}
self.xc.domain_hvm_setcontext(
self.domid,
buffer,
size.try_into().map_err(XenDriverError::from)?,
)?;
Ok(())
}
fn listen(&mut self, timeout: u32) -> Result<Option<Event>, Box<dyn Error>> {
let fd = self.xev.xenevtchn_fd().map_err(XenDriverError::from)?;
let fd_struct = PollFd::new(fd, PollFlags::POLLIN | PollFlags::POLLERR);
let mut fds = [fd_struct];
let mut vcpu: u16 = 0;
let mut event_type = unsafe { mem::MaybeUninit::<EventType>::zeroed().assume_init() };
let poll_result = poll(&mut fds, timeout.try_into().map_err(XenDriverError::from)?)?;
let mut pending_event_port = -1;
if poll_result == 1 {
pending_event_port = self.xev.xenevtchn_pending().map_err(XenDriverError::from)?;
if pending_event_port != -1 {
self.xev
.xenevtchn_unmask(
pending_event_port
.try_into()
.map_err(XenDriverError::from)?,
)
.map_err(XenDriverError::from)?;
}
}
let back_ring_ptr = &mut self.back_ring;
let mut flag = false;
if poll_result > 0
&& self.xev.get_bind_port() == pending_event_port
&& RING_HAS_UNCONSUMED_REQUESTS!(back_ring_ptr) != 0
{
flag = true;
let req = self.xc.get_request(back_ring_ptr)?;
if req.version != VM_EVENT_INTERFACE_VERSION {
return Err(Box::new(XenDriverError::EventVersionMismatch(
req.version,
VM_EVENT_INTERFACE_VERSION,
)));
}
let xen_event_type = (self.xc.get_event_type(req)).map_err(XenDriverError::from)?;
event_type = match xen_event_type {
XenEventType::Cr { cr_type, new, old } => EventType::Cr {
cr_type: match cr_type {
XenCr::Cr0 => CrType::Cr0,
XenCr::Cr3 => CrType::Cr3,
XenCr::Cr4 => CrType::Cr4,
},
new,
old,
},
XenEventType::Msr { msr_type, value } => EventType::Msr { msr_type, value },
XenEventType::Breakpoint { insn_len, .. } => {
EventType::Breakpoint { gpa: 0, insn_len }
}
_ => unimplemented!(),
};
vcpu = req.vcpu_id.try_into().map_err(XenDriverError::from)?;
let mut rsp =
unsafe { mem::MaybeUninit::<vm_event_response_t>::zeroed().assume_init() };
rsp.reason = req.reason;
rsp.version = VM_EVENT_INTERFACE_VERSION;
rsp.vcpu_id = req.vcpu_id;
rsp.flags = req.flags & VM_EVENT_FLAG_VCPU_PAUSED;
self.xc
.put_response(&mut rsp, &mut self.back_ring)
.map_err(XenDriverError::from)?;
}
self.xev.xenevtchn_notify().map_err(XenDriverError::from)?;
if flag {
Ok(Some(Event {
vcpu,
kind: event_type,
}))
} else {
Ok(None)
}
}
fn toggle_intercept(
&mut self,
_vcpu: u16,
intercept_type: InterceptType,
enabled: bool,
) -> Result<(), Box<dyn Error>> {
match intercept_type {
InterceptType::Cr(micro_cr_type) => {
let xen_cr = match micro_cr_type {
CrType::Cr0 => XenCr::Cr0,
CrType::Cr3 => XenCr::Cr3,
CrType::Cr4 => XenCr::Cr4,
};
Ok(self
.xc
.monitor_write_ctrlreg(self.domid, xen_cr, enabled, true, true)
.map_err(XenDriverError::from)?)
}
InterceptType::Msr(micro_msr_type) => Ok(self
.xc
.monitor_mov_to_msr(self.domid, micro_msr_type, enabled)
.map_err(XenDriverError::from)?),
InterceptType::Breakpoint => Ok(self
.xc
.monitor_software_breakpoint(self.domid, enabled)
.map_err(XenDriverError::from)?),
_ => unimplemented!(),
}
}
fn pause(&mut self) -> Result<(), Box<dyn Error>> {
debug!("pause");
Ok(self
.xc
.domain_pause(self.domid)
.map_err(XenDriverError::from)?)
}
fn resume(&mut self) -> Result<(), Box<dyn Error>> {
debug!("resume");
Ok(self
.xc
.domain_unpause(self.domid)
.map_err(XenDriverError::from)?)
}
fn get_driver_type(&self) -> DriverType {
DriverType::Xen
}
}
impl Drop for Xen {
fn drop(&mut self) {
debug!("Closing Xen driver");
self.xc
.monitor_disable(self.domid)
.expect("Failed to unmap event ring page");
}
}