diff --git a/pvmfw/src/smccc.rs b/pvmfw/src/smccc.rs
new file mode 100644
index 0000000..e3a2b05
--- /dev/null
+++ b/pvmfw/src/smccc.rs
@@ -0,0 +1,115 @@
+// Copyright 2022, The Android Open Source Project
+//
+// 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 core::fmt;
+
+// TODO(b/245889995): use psci-0.1.1 crate
+#[inline(always)]
+fn hvc64(function: u32, args: [u64; 17]) -> [u64; 18] {
+    #[cfg(target_arch = "aarch64")]
+    unsafe {
+        let mut ret = [0; 18];
+
+        core::arch::asm!(
+            "hvc #0",
+            inout("x0") function as u64 => ret[0],
+            inout("x1") args[0] => ret[1],
+            inout("x2") args[1] => ret[2],
+            inout("x3") args[2] => ret[3],
+            inout("x4") args[3] => ret[4],
+            inout("x5") args[4] => ret[5],
+            inout("x6") args[5] => ret[6],
+            inout("x7") args[6] => ret[7],
+            inout("x8") args[7] => ret[8],
+            inout("x9") args[8] => ret[9],
+            inout("x10") args[9] => ret[10],
+            inout("x11") args[10] => ret[11],
+            inout("x12") args[11] => ret[12],
+            inout("x13") args[12] => ret[13],
+            inout("x14") args[13] => ret[14],
+            inout("x15") args[14] => ret[15],
+            inout("x16") args[15] => ret[16],
+            inout("x17") args[16] => ret[17],
+            options(nomem, nostack)
+        );
+
+        ret
+    }
+}
+
+/// Standard SMCCC error values as described in DEN 0028E.
+#[derive(Debug, Clone)]
+pub enum Error {
+    /// The call is not supported by the implementation.
+    NotSupported,
+    /// The call is deemed not required by the implementation.
+    NotRequired,
+    /// One of the call parameters has a non-supported value.
+    InvalidParameter,
+    /// Negative values indicate error.
+    Unknown(i64),
+    /// The call returned a positive value when 0 was expected.
+    Unexpected(u64),
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Self::NotSupported => write!(f, "SMCCC call not supported"),
+            Self::NotRequired => write!(f, "SMCCC call not required"),
+            Self::InvalidParameter => write!(f, "SMCCC call received non-supported value"),
+            Self::Unexpected(v) => write!(f, "Unexpected SMCCC return value '{}'", v),
+            Self::Unknown(e) => write!(f, "Unknown SMCCC return value '{}'", e),
+        }
+    }
+}
+
+fn check_smccc_err(ret: i64) -> Result<(), Error> {
+    match check_smccc_value(ret)? {
+        0 => Ok(()),
+        v => Err(Error::Unexpected(v)),
+    }
+}
+
+fn check_smccc_value(ret: i64) -> Result<u64, Error> {
+    match ret {
+        x if x >= 0 => Ok(ret as u64),
+        -1 => Err(Error::NotSupported),
+        -2 => Err(Error::NotRequired),
+        -3 => Err(Error::InvalidParameter),
+        _ => Err(Error::Unknown(ret)),
+    }
+}
+
+const VENDOR_HYP_KVM_MMIO_GUARD_INFO_FUNC_ID: u32 = 0xc6000005;
+const VENDOR_HYP_KVM_MMIO_GUARD_MAP_FUNC_ID: u32 = 0xc6000007;
+
+/// Issue pKVM-specific MMIO_GUARD_INFO HVC64.
+pub fn mmio_guard_info() -> Result<u64, Error> {
+    let args = [0u64; 17];
+
+    let res = hvc64(VENDOR_HYP_KVM_MMIO_GUARD_INFO_FUNC_ID, args);
+
+    check_smccc_value(res[0] as i64)
+}
+
+/// Issue pKVM-specific MMIO_GUARD_MAP HVC64.
+pub fn mmio_guard_map(ipa: u64) -> Result<(), Error> {
+    let mut args = [0u64; 17];
+    args[0] = ipa;
+
+    let res = hvc64(VENDOR_HYP_KVM_MMIO_GUARD_MAP_FUNC_ID, args);
+
+    check_smccc_err(res[0] as i64)
+}