From 349247860c8a738e0fc9aac2b8db83144f8d5481 Mon Sep 17 00:00:00 2001
From: Tina Zhang <tina.zhang@intel.corp-partner.google.com>
Date: Fri, 22 Apr 2022 15:42:12 +0800
Subject: [PATCH] devices: virtio: iommu: assign a sensible default value to
 page_size_mask

Assign a sensible default value to page_size_mask and reject the empty
page_size_mask case.

BUG=b:185084350
TEST=Boot a crosvm guest with vIOMMU enabled

Change-Id: Id711c9ff25265f707618a58eb212fd5ca16383e8
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3580372
Reviewed-by: David Stevens <stevensd@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Keiichi Watanabe <keiichiw@chromium.org>
Commit-Queue: David Stevens <stevensd@chromium.org>
---
 devices/src/virtio/iommu.rs | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/devices/src/virtio/iommu.rs b/devices/src/virtio/iommu.rs
index 80bcc202a3..27ede3ebc5 100644
--- a/devices/src/virtio/iommu.rs
+++ b/devices/src/virtio/iommu.rs
@@ -753,7 +753,7 @@ impl Iommu {
         translate_request_rx: Option<Tube>,
         iommu_device_tube: Option<Tube>,
     ) -> SysResult<Iommu> {
-        let mut page_size_mask = !0_u64;
+        let mut page_size_mask = !((pagesize() as u64) - 1);
         for (_, container) in endpoints.iter() {
             page_size_mask &= container
                 .lock()
@@ -762,9 +762,7 @@ impl Iommu {
         }
 
         if page_size_mask == 0 {
-            // In case no endpoints bounded to vIOMMU during system booting,
-            // assume IOVA page size is the same as page_size
-            page_size_mask = (pagesize() as u64) - 1;
+            return Err(SysError::new(libc::EIO));
         }
 
         let input_range = virtio_iommu_range_64 {