Merge changes I974e9783,I74c2d43d,I65a4804e
* changes:
pvmfw: Hack MMIO_GUARD_MAP to expect i32
pvmfw: Hack MMIO_GUARD_UNMAP to expect NOT_SUPPORTED
pvmfw: Issue MMIO_GUARD_UNMAP for UART
diff --git a/pvmfw/src/entry.rs b/pvmfw/src/entry.rs
index a606462..99c67fb 100644
--- a/pvmfw/src/entry.rs
+++ b/pvmfw/src/entry.rs
@@ -18,7 +18,7 @@
use crate::mmio_guard;
use core::arch::asm;
use core::slice;
-use log::{debug, LevelFilter};
+use log::{debug, error, LevelFilter};
use vmbase::{console, logger, main, power::reboot};
#[derive(Debug, Clone)]
@@ -77,6 +77,11 @@
// This wrapper allows main() to be blissfully ignorant of platform details.
crate::main(fdt, payload);
+ mmio_guard::unmap(console::BASE_ADDRESS).map_err(|e| {
+ error!("Failed to unshare the UART: {e}");
+ RebootReason::InternalError
+ })?;
+
Ok(())
}
diff --git a/pvmfw/src/mmio_guard.rs b/pvmfw/src/mmio_guard.rs
index 421f2c4..eb6c1fa 100644
--- a/pvmfw/src/mmio_guard.rs
+++ b/pvmfw/src/mmio_guard.rs
@@ -17,6 +17,7 @@
use crate::helpers;
use crate::smccc;
use core::{fmt, result};
+use log::info;
#[derive(Debug, Clone)]
pub enum Error {
@@ -26,6 +27,8 @@
InfoFailed(smccc::Error),
/// Failed to MMIO_GUARD_MAP a page.
MapFailed(smccc::Error),
+ /// Failed to MMIO_GUARD_UNMAP a page.
+ UnmapFailed(smccc::Error),
/// The MMIO_GUARD granule used by the hypervisor is not supported.
UnsupportedGranule(usize),
}
@@ -38,6 +41,7 @@
Self::EnrollFailed(e) => write!(f, "Failed to enroll into MMIO_GUARD: {e}"),
Self::InfoFailed(e) => write!(f, "Failed to get the MMIO_GUARD granule: {e}"),
Self::MapFailed(e) => write!(f, "Failed to MMIO_GUARD map: {e}"),
+ Self::UnmapFailed(e) => write!(f, "Failed to MMIO_GUARD unmap: {e}"),
Self::UnsupportedGranule(g) => write!(f, "Unsupported MMIO_GUARD granule: {g}"),
}
}
@@ -56,6 +60,10 @@
mmio_guard_map(helpers::page_4kb_of(addr) as u64).map_err(Error::MapFailed)
}
+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];
@@ -75,5 +83,31 @@
let mut args = [0u64; 17];
args[0] = ipa;
- smccc::checked_hvc64_expect_zero(VENDOR_HYP_KVM_MMIO_GUARD_MAP_FUNC_ID, args)
+ // 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.
+ info!("Expecting a bug making MMIO_GUARD_UNMAP return NOT_SUPPORTED on success");
+ match smccc::checked_hvc64_expect_zero(VENDOR_HYP_KVM_MMIO_GUARD_UNMAP_FUNC_ID, args) {
+ Err(smccc::Error::NotSupported) | Ok(_) => Ok(()),
+ x => x,
+ }
}