commit 2df297fb718c1105314e0be7410cde9a8cc2edb2
author Srivatsa Vaddagiri <quic_svaddagi@quicinc.com> Wed Apr 12 03:11:05 2023 -0700
committer Srivatsa Vaddagiri <quic_svaddagi@quicinc.com> Thu Apr 27 16:26:21 2023 +0530
tree 9981aeb7db74024683a08118d72201795ee94fd6
parent c25d68ebeeb586ab5eb26af5c0a69d8511904f8f

[pvmfw] Account for swiotlb 'reg' property

Swiotlb node could optionally convey an address range via 'reg'
property. On Gunyah platform, it represents the memory range that has
been shared with host OS prior to VM starting its execution.
Recognize existence of such property and pass it on to the VM in
patched device-tree.

Test: m pvmfw_img
Bug: 271493784
Change-Id: I04e69f4dd9422ff08e12830e870d6169ba4811da

pvmfw/src/fdt.rs

diff --git a/pvmfw/src/fdt.rs b/pvmfw/src/fdt.rs
index c68fc6d..065159c 100644
--- a/pvmfw/src/fdt.rs
+++ b/pvmfw/src/fdt.rs
@@ -17,6 +17,7 @@
 use crate::bootargs::BootArgsIterator;
 use crate::cstr;
 use crate::helpers::flatten;
+use crate::helpers::RangeExt;
 use crate::helpers::GUEST_PAGE_SIZE;
 use crate::helpers::SIZE_4KB;
 use crate::memory::BASE_ADDR;
@@ -436,39 +437,78 @@
 
 #[derive(Debug)]
 struct SwiotlbInfo {
-    size: u64,
-    align: u64,
+    addr: Option<usize>,
+    size: usize,
+    align: usize,
+}
+
+impl SwiotlbInfo {
+    pub fn fixed_range(&self) -> Option<Range<usize>> {
+        self.addr.map(|addr| addr..addr + self.size)
+    }
 }
 
 fn read_swiotlb_info_from(fdt: &Fdt) -> libfdt::Result<SwiotlbInfo> {
     let node =
         fdt.compatible_nodes(cstr!("restricted-dma-pool"))?.next().ok_or(FdtError::NotFound)?;
-    let size = node.getprop_u64(cstr!("size"))?.ok_or(FdtError::NotFound)?;
-    let align = node.getprop_u64(cstr!("alignment"))?.ok_or(FdtError::NotFound)?;
-    Ok(SwiotlbInfo { size, align })
+    let align =
+        node.getprop_u64(cstr!("alignment"))?.ok_or(FdtError::NotFound)?.try_into().unwrap();
+
+    let (addr, size) = if let Some(mut reg) = node.reg()? {
+        let reg = reg.next().ok_or(FdtError::NotFound)?;
+        let size = reg.size.ok_or(FdtError::NotFound)?;
+        reg.addr.checked_add(size).ok_or(FdtError::BadValue)?;
+        (Some(reg.addr.try_into().unwrap()), size.try_into().unwrap())
+    } else {
+        let size = node.getprop_u64(cstr!("size"))?.ok_or(FdtError::NotFound)?.try_into().unwrap();
+        (None, size)
+    };
+
+    Ok(SwiotlbInfo { addr, size, align })
 }
 
-fn validate_swiotlb_info(swiotlb_info: &SwiotlbInfo) -> Result<(), RebootReason> {
+fn validate_swiotlb_info(
+    swiotlb_info: &SwiotlbInfo,
+    memory: &Range<usize>,
+) -> Result<(), RebootReason> {
     let size = swiotlb_info.size;
     let align = swiotlb_info.align;
 
-    if size == 0 || (size % GUEST_PAGE_SIZE as u64) != 0 {
+    if size == 0 || (size % GUEST_PAGE_SIZE) != 0 {
         error!("Invalid swiotlb size {:#x}", size);
         return Err(RebootReason::InvalidFdt);
     }
 
-    if (align % GUEST_PAGE_SIZE as u64) != 0 {
+    if (align % GUEST_PAGE_SIZE) != 0 {
         error!("Invalid swiotlb alignment {:#x}", align);
         return Err(RebootReason::InvalidFdt);
     }
+
+    if let Some(range) = swiotlb_info.fixed_range() {
+        if !range.is_within(memory) {
+            error!("swiotlb range {range:#x?} not part of memory range {memory:#x?}");
+            return Err(RebootReason::InvalidFdt);
+        }
+    }
+
     Ok(())
 }
 
 fn patch_swiotlb_info(fdt: &mut Fdt, swiotlb_info: &SwiotlbInfo) -> libfdt::Result<()> {
     let mut node =
         fdt.root_mut()?.next_compatible(cstr!("restricted-dma-pool"))?.ok_or(FdtError::NotFound)?;
-    node.setprop_inplace(cstr!("size"), &swiotlb_info.size.to_be_bytes())?;
     node.setprop_inplace(cstr!("alignment"), &swiotlb_info.align.to_be_bytes())?;
+
+    if let Some(range) = swiotlb_info.fixed_range() {
+        node.appendprop_addrrange(
+            cstr!("reg"),
+            range.start.try_into().unwrap(),
+            range.len().try_into().unwrap(),
+        )?;
+    } else {
+        node.setprop_inplace(cstr!("size"), &swiotlb_info.size.to_be_bytes())?;
+    }
+
     Ok(())
 }
 
@@ -603,7 +643,7 @@
         error!("Failed to read swiotlb info from DT: {e}");
         RebootReason::InvalidFdt
     })?;
-    validate_swiotlb_info(&swiotlb_info)?;
+    validate_swiotlb_info(&swiotlb_info, &memory_range)?;
 
     Ok(DeviceTreeInfo {
         kernel_range,