hypervisor: mshv: explicitly skip a few IO ports

OVMF would use string IO on those ports. String IO has not been
implemented, so that leads to panics.

Skip them explicitly in MSHV. Leave a long-ish comment in code to
explain the situation. We should properly implement string IO once it
becomes feasible / necessary.

Signed-off-by: Wei Liu <liuwe@microsoft.com>
This commit is contained in:
Wei Liu 2020-12-10 16:26:42 +00:00 committed by Samuel Ortiz
parent a330a1569a
commit 29881a2d6a

View File

@ -322,17 +322,52 @@ impl cpu::Vcpu for MshvVcpu {
hv_message_type_HVMSG_X64_IO_PORT_INTERCEPT => {
let info = x.to_ioport_info().unwrap();
let access_info = info.access_info;
let len = unsafe { access_info.__bindgen_anon_1.access_size() } as usize;
let is_write = info.header.intercept_access_type == 1;
let port = info.port_number;
let mut data: [u8; 4] = [0; 4];
let mut ret_rax = info.rax;
/*
* XXX: Ignore QEMU fw_cfg (0x5xx) and debug console (0x402) ports.
*
* Cloud Hypervisor doesn't support fw_cfg at the moment. It does support 0x402
* under the "fwdebug" feature flag. But that feature is not enabled by default
* and is considered legacy.
*
* OVMF unconditionally pokes these IO ports with string IO.
*
* Instead of trying to implement string IO support now which does not do much
* now, skip those ports explicitly to avoid panicking.
*
* Proper string IO support can be added once we gain the ability to translate
* guest virtual addresses to guest physical addresses on MSHV.
*/
match port {
0x402 | 0x510 | 0x511 | 0x514 => {
let insn_len = info.header.instruction_length() as u64;
/* Advance RIP and update RAX */
let arr_reg_name_value = [
(
hv_register_name::HV_X64_REGISTER_RIP,
info.header.rip + insn_len,
),
(hv_register_name::HV_X64_REGISTER_RAX, ret_rax),
];
set_registers_64!(self.fd, arr_reg_name_value)
.map_err(|e| cpu::HypervisorCpuError::SetRegister(e.into()))?;
return Ok(cpu::VmExit::Ignore);
}
_ => {}
}
if unsafe { access_info.__bindgen_anon_1.string_op() } == 1 {
panic!("String IN/OUT not supported");
}
if unsafe { access_info.__bindgen_anon_1.rep_prefix() } == 1 {
panic!("Rep IN/OUT not supported");
}
let len = unsafe { access_info.__bindgen_anon_1.access_size() } as usize;
let is_write = info.header.intercept_access_type == 1;
let port = info.port_number;
let mut data: [u8; 4] = [0; 4];
let mut ret_rax = info.rax;
if is_write {
let data = (info.rax as u32).to_le_bytes();