hypervisor: Add support for handling SEV INFO request

As part of handling this request, hypervisor is expected to three
things:

1. Maximum GHCB protocol version supported.
2. Minimum GHCB protocol version supported.
3. SEV-page table encryption bit number.

If the guest cannot support the protocol range supplied by the
hypervisor, it should terminate

Signed-off-by: Muminul Islam <muislam@microsoft.com>
Signed-off-by: Jinank Jain <jinankjain@microsoft.com>
This commit is contained in:
Jinank Jain 2023-10-18 12:13:48 +00:00 committed by Bo Chen
parent 6f4d82bd61
commit d68fec594e

View File

@ -693,6 +693,29 @@ impl cpu::Vcpu for MshvVcpu {
set_registers_64!(self.fd, reg_name_value) set_registers_64!(self.fd, reg_name_value)
.map_err(|e| cpu::HypervisorCpuError::SetRegister(e.into()))?; .map_err(|e| cpu::HypervisorCpuError::SetRegister(e.into()))?;
} }
GHCB_INFO_SEV_INFO_REQUEST => {
let sev_cpuid_function = 0x8000_001F;
let cpu_leaf = self
.fd
.get_cpuid_values(sev_cpuid_function, 0, 0, 0)
.unwrap();
let ebx = cpu_leaf[1];
// First 6-byte of EBX represents page table encryption bit number
let pbit_encryption = (ebx & 0x3f) as u8;
let mut ghcb_response = GHCB_INFO_SEV_INFO_RESPONSE as u64;
// GHCBData[63:48] specifies the maximum GHCB protocol version supported
ghcb_response |= (GHCB_PROTOCOL_VERSION_MAX as u64) << 48;
// GHCBData[47:32] specifies the minimum GHCB protocol version supported
ghcb_response |= (GHCB_PROTOCOL_VERSION_MIN as u64) << 32;
// GHCBData[31:24] specifies the SEV page table encryption bit number.
ghcb_response |= (pbit_encryption as u64) << 24;
let arr_reg_name_value =
[(hv_register_name_HV_X64_REGISTER_GHCB, ghcb_response)];
set_registers_64!(self.fd, arr_reg_name_value)
.map_err(|e| cpu::HypervisorCpuError::SetRegister(e.into()))?;
}
_ => panic!("Unsupported VMGEXIT operation: {:0x}", ghcb_op), _ => panic!("Unsupported VMGEXIT operation: {:0x}", ghcb_op),
} }