Move HVC constants and wrappers to new module.

Bug: 261439403
Test: ran pVM firmware manually
Change-Id: I5ebf9013efa3a723dd975d36fd4fa0859c154127
diff --git a/pvmfw/src/hvc.rs b/pvmfw/src/hvc.rs
new file mode 100644
index 0000000..66f7977
--- /dev/null
+++ b/pvmfw/src/hvc.rs
@@ -0,0 +1,66 @@
+// 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.
+
+//! Wrappers around calls to the hypervisor.
+
+use crate::smccc::{self, checked_hvc64, checked_hvc64_expect_zero};
+use log::info;
+
+const VENDOR_HYP_KVM_MMIO_GUARD_INFO_FUNC_ID: u32 = 0xc6000005;
+const VENDOR_HYP_KVM_MMIO_GUARD_ENROLL_FUNC_ID: u32 = 0xc6000006;
+const VENDOR_HYP_KVM_MMIO_GUARD_MAP_FUNC_ID: u32 = 0xc6000007;
+const VENDOR_HYP_KVM_MMIO_GUARD_UNMAP_FUNC_ID: u32 = 0xc6000008;
+
+pub fn mmio_guard_info() -> smccc::Result<u64> {
+    let args = [0u64; 17];
+
+    checked_hvc64(VENDOR_HYP_KVM_MMIO_GUARD_INFO_FUNC_ID, args)
+}
+
+pub fn mmio_guard_enroll() -> smccc::Result<()> {
+    let args = [0u64; 17];
+
+    checked_hvc64_expect_zero(VENDOR_HYP_KVM_MMIO_GUARD_ENROLL_FUNC_ID, args)
+}
+
+pub fn mmio_guard_map(ipa: u64) -> smccc::Result<()> {
+    let mut args = [0u64; 17];
+    args[0] = ipa;
+
+    // TODO(b/253586500): pKVM currently returns a i32 instead of a i64.
+    let is_i32_error_code = |n| u32::try_from(n).ok().filter(|v| (*v as i32) < 0).is_some();
+    match checked_hvc64_expect_zero(VENDOR_HYP_KVM_MMIO_GUARD_MAP_FUNC_ID, args) {
+        Err(smccc::Error::Unexpected(e)) if is_i32_error_code(e) => {
+            info!("Handled a pKVM bug by interpreting the MMIO_GUARD_MAP return value as i32");
+            match e as u32 as i32 {
+                -1 => Err(smccc::Error::NotSupported),
+                -2 => Err(smccc::Error::NotRequired),
+                -3 => Err(smccc::Error::InvalidParameter),
+                ret => Err(smccc::Error::Unknown(ret as i64)),
+            }
+        }
+        res => res,
+    }
+}
+
+pub fn mmio_guard_unmap(ipa: u64) -> smccc::Result<()> {
+    let mut args = [0u64; 17];
+    args[0] = ipa;
+
+    // TODO(b/251426790): pKVM currently returns NOT_SUPPORTED for SUCCESS.
+    match checked_hvc64_expect_zero(VENDOR_HYP_KVM_MMIO_GUARD_UNMAP_FUNC_ID, args) {
+        Err(smccc::Error::NotSupported) | Ok(_) => Ok(()),
+        x => x,
+    }
+}
diff --git a/pvmfw/src/main.rs b/pvmfw/src/main.rs
index 79b6f57..2f1b42a 100644
--- a/pvmfw/src/main.rs
+++ b/pvmfw/src/main.rs
@@ -26,6 +26,7 @@
 mod fdt;
 mod heap;
 mod helpers;
+mod hvc;
 mod memory;
 mod mmio_guard;
 mod mmu;
diff --git a/pvmfw/src/mmio_guard.rs b/pvmfw/src/mmio_guard.rs
index 28f928f..e5f376e 100644
--- a/pvmfw/src/mmio_guard.rs
+++ b/pvmfw/src/mmio_guard.rs
@@ -15,9 +15,9 @@
 //! Safe MMIO_GUARD support.
 
 use crate::helpers;
+use crate::hvc::{mmio_guard_enroll, mmio_guard_info, mmio_guard_map, mmio_guard_unmap};
 use crate::smccc;
 use core::{fmt, result};
-use log::info;
 
 #[derive(Debug, Clone)]
 pub enum Error {
@@ -63,50 +63,3 @@
 pub fn unmap(addr: usize) -> Result<()> {
     mmio_guard_unmap(helpers::page_4kb_of(addr) as u64).map_err(Error::UnmapFailed)
 }
-
-fn mmio_guard_info() -> smccc::Result<u64> {
-    const VENDOR_HYP_KVM_MMIO_GUARD_INFO_FUNC_ID: u32 = 0xc6000005;
-    let args = [0u64; 17];
-
-    smccc::checked_hvc64(VENDOR_HYP_KVM_MMIO_GUARD_INFO_FUNC_ID, args)
-}
-
-fn mmio_guard_enroll() -> smccc::Result<()> {
-    const VENDOR_HYP_KVM_MMIO_GUARD_ENROLL_FUNC_ID: u32 = 0xc6000006;
-    let args = [0u64; 17];
-
-    smccc::checked_hvc64_expect_zero(VENDOR_HYP_KVM_MMIO_GUARD_ENROLL_FUNC_ID, args)
-}
-
-fn mmio_guard_map(ipa: u64) -> smccc::Result<()> {
-    const VENDOR_HYP_KVM_MMIO_GUARD_MAP_FUNC_ID: u32 = 0xc6000007;
-    let mut args = [0u64; 17];
-    args[0] = ipa;
-
-    // TODO(b/253586500): pKVM currently returns a i32 instead of a i64.
-    let is_i32_error_code = |n| u32::try_from(n).ok().filter(|v| (*v as i32) < 0).is_some();
-    match smccc::checked_hvc64_expect_zero(VENDOR_HYP_KVM_MMIO_GUARD_MAP_FUNC_ID, args) {
-        Err(smccc::Error::Unexpected(e)) if is_i32_error_code(e) => {
-            info!("Handled a pKVM bug by interpreting the MMIO_GUARD_MAP return value as i32");
-            match e as u32 as i32 {
-                -1 => Err(smccc::Error::NotSupported),
-                -2 => Err(smccc::Error::NotRequired),
-                -3 => Err(smccc::Error::InvalidParameter),
-                ret => Err(smccc::Error::Unknown(ret as i64)),
-            }
-        }
-        res => res,
-    }
-}
-
-fn mmio_guard_unmap(ipa: u64) -> smccc::Result<()> {
-    const VENDOR_HYP_KVM_MMIO_GUARD_UNMAP_FUNC_ID: u32 = 0xc6000008;
-    let mut args = [0u64; 17];
-    args[0] = ipa;
-
-    // TODO(b/251426790): pKVM currently returns NOT_SUPPORTED for SUCCESS.
-    match smccc::checked_hvc64_expect_zero(VENDOR_HYP_KVM_MMIO_GUARD_UNMAP_FUNC_ID, args) {
-        Err(smccc::Error::NotSupported) | Ok(_) => Ok(()),
-        x => x,
-    }
-}