commit a4a46df15e7ced0d52dd3f42ef391c8b7064a279
author David Stevens <stevensd@chromium.org> Fri Jun 17 17:30:25 2022 +0900
committer Chromeos LUCI <chromeos-scoped@luci-project-accounts.iam.gserviceaccount.com> Fri Jun 17 09:15:19 2022 +0000
tree a7e6fca588d943cefb21873fb82126ea71d4197b
parent 89479b41dbd39b9c87b5d93e88971c5615ee73d1

x86_64: fix e820 computation

Exclude pci mmio region below 4gb from the e820 table. This is a
followup to CL:3696671.

BUG=None
TEST=arc.Boot.vm

Change-Id: I07c2b9a9e2e4e27682c4b60406625b019eea195f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3708390
Reviewed-by: Junichi Uekawa <uekawa@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: David Stevens <stevensd@chromium.org>

x86_64/src/lib.rs

diff --git a/x86_64/src/lib.rs b/x86_64/src/lib.rs
index 60577dc..140ba46 100644
--- a/x86_64/src/lib.rs
+++ b/x86_64/src/lib.rs
@@ -369,13 +369,17 @@
         E820Type::Ram,
     )?;
 
-    let ram_region = AddressRange {
+    // GuestMemory::end_addr() returns the first address past the end, so subtract 1 to get the
+    // inclusive end.
+    let guest_mem_end = guest_mem.end_addr().offset() - 1;
+    let ram_below_4g = AddressRange {
         start: kernel_addr.offset(),
-        // GuestMemory::end_addr() returns the first address past the end, so subtract 1 to get the
-        // inclusive end.
-        end: guest_mem.end_addr().offset() - 1,
+        end: guest_mem_end.min(read_pci_mmio_before_32bit().start - 1),
     };
-    let (ram_below_4g, ram_above_4g) = ram_region.split_at(FIRST_ADDR_PAST_32BITS);
+    let ram_above_4g = AddressRange {
+        start: FIRST_ADDR_PAST_32BITS,
+        end: guest_mem_end,
+    };
     add_e820_entry(&mut params, ram_below_4g, E820Type::Ram)?;
     if !ram_above_4g.is_empty() {
         add_e820_entry(&mut params, ram_above_4g, E820Type::Ram)?