pvmfw: Map image footer after dynamic PT switch
Teach the MemoryTracker to map the optional image footer into the
dynamic PTs. As vmbase now knows internally where it is located, there
is no need to receive the "payload range" from the client anymore.
Therefore, refactor MemoryTracker::new() to stop taking that argument.
As a result, pvmfw now first switches to the dynamic PTs before
requesting the footer to be mapped, which prepares it (along with other
vmbase clients) for an upcoming change that will activate the dynamic
PTs before it is entered from vmbase.
As the MemoryTracker keeps track of whether the footer has been mapped,
get_appended_data_slice() can now safely return a Result<&mut> as it
will fail if called more than once.
Note that the memory tracker uses dirty-bit tracking (flushed when
switching back to the static PTs) for the image footer.
Bug: 377276983
Test: m {pvmfw,rialto,vmbase_example_{bios,kernel}}_bin
Test: atest rialto_test vmbase_example.integration_test
Change-Id: I24954b6905db0a0a499f7aa2dedb9a4e5b83d168
diff --git a/guest/pvmfw/src/entry.rs b/guest/pvmfw/src/entry.rs
index 48585f3..e55d4ca 100644
--- a/guest/pvmfw/src/entry.rs
+++ b/guest/pvmfw/src/entry.rs
@@ -31,7 +31,7 @@
configure_heap, console_writeln,
layout::{self, crosvm, UART_PAGE_ADDR},
main,
- memory::{MemoryTracker, MEMORY, SIZE_128KB, SIZE_4KB},
+ memory::{MemoryTracker, MemoryTrackerError, MEMORY, SIZE_128KB, SIZE_4KB},
power::reboot,
};
use zeroize::Zeroize;
@@ -113,9 +113,17 @@
RebootReason::InternalError
})?;
- // SAFETY: We only get the appended payload from here, once. The region was statically mapped,
- // then remapped by `init_page_table()`.
- let appended_data = unsafe { get_appended_data_slice() };
+ // Up to this point, we were using the built-in static (from .rodata) page tables.
+ MEMORY.lock().replace(MemoryTracker::new(
+ page_table,
+ crosvm::MEM_START..layout::MAX_VIRT_ADDR,
+ crosvm::MMIO_RANGE,
+ ));
+
+ let appended_data = get_appended_data_slice().map_err(|e| {
+ error!("Failed to map the appended data: {e}");
+ RebootReason::InternalError
+ })?;
let appended = AppendedPayload::new(appended_data).ok_or_else(|| {
error!("No valid configuration found");
@@ -124,14 +132,6 @@
let config_entries = appended.get_entries();
- // Up to this point, we were using the built-in static (from .rodata) page tables.
- MEMORY.lock().replace(MemoryTracker::new(
- page_table,
- crosvm::MEM_START..layout::MAX_VIRT_ADDR,
- crosvm::MMIO_RANGE,
- Some(layout::image_footer_range()),
- ));
-
let slices = memory::MemorySlices::new(
fdt,
payload,
@@ -321,15 +321,11 @@
};
}
-/// # Safety
-///
-/// This must only be called once, since we are returning a mutable reference.
-/// The appended data region must be mapped.
-unsafe fn get_appended_data_slice() -> &'static mut [u8] {
- let range = layout::image_footer_range();
- // SAFETY: This region is mapped and the linker script prevents it from overlapping with other
- // objects.
- unsafe { slice::from_raw_parts_mut(range.start.0 as *mut u8, range.end - range.start) }
+fn get_appended_data_slice() -> Result<&'static mut [u8], MemoryTrackerError> {
+ let range = MEMORY.lock().as_mut().unwrap().map_image_footer()?;
+ // SAFETY: This region was just mapped for the first time (as map_image_footer() didn't fail)
+ // and the linker script prevents it from overlapping with other objects.
+ Ok(unsafe { slice::from_raw_parts_mut(range.start as *mut u8, range.len()) })
}
enum AppendedPayload<'a> {
diff --git a/guest/pvmfw/src/memory.rs b/guest/pvmfw/src/memory.rs
index 7d49bca..64a6850 100644
--- a/guest/pvmfw/src/memory.rs
+++ b/guest/pvmfw/src/memory.rs
@@ -50,7 +50,6 @@
page_table.map_data(&stack_range().into())?;
page_table.map_code(&layout::text_range().into())?;
page_table.map_rodata(&layout::rodata_range().into())?;
- page_table.map_data_dbm(&layout::image_footer_range().into())?;
if let Err(e) = page_table.map_device(&layout::console_uart_page().into()) {
error!("Failed to remap the UART as a dynamic page table entry: {e}");
return Err(e);