From ee1899c6f6954a6e5dec1a710e0617ea537b9890 Mon Sep 17 00:00:00 2001
From: Sebastien Boeuf <sebastien.boeuf@intel.com>
Date: Fri, 4 Oct 2019 10:36:47 -0700
Subject: [PATCH] vm-virtio: Add IOMMU support to virtio-pmem

Adding virtio feature VIRTIO_F_IOMMU_PLATFORM when explicitly asked by
the user. The need for this feature is to be able to attach the virtio
device to a virtual IOMMU.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
---
 vm-virtio/src/pmem.rs     | 12 +++++++++---
 vmm/src/device_manager.rs |  2 +-
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/vm-virtio/src/pmem.rs b/vm-virtio/src/pmem.rs
index c1f5cb93c..940d89626 100644
--- a/vm-virtio/src/pmem.rs
+++ b/vm-virtio/src/pmem.rs
@@ -21,7 +21,7 @@ use std::thread;
 use super::Error as DeviceError;
 use super::{
     ActivateError, ActivateResult, DescriptorChain, DeviceEventT, Queue, VirtioDevice,
-    VirtioDeviceType, VIRTIO_F_VERSION_1,
+    VirtioDeviceType, VIRTIO_F_IOMMU_PLATFORM, VIRTIO_F_VERSION_1,
 };
 use crate::{VirtioInterrupt, VirtioInterruptType};
 use vm_memory::{
@@ -296,16 +296,22 @@ pub struct Pmem {
 }
 
 impl Pmem {
-    pub fn new(disk: File, addr: GuestAddress, size: GuestUsize) -> io::Result<Pmem> {
+    pub fn new(disk: File, addr: GuestAddress, size: GuestUsize, iommu: bool) -> io::Result<Pmem> {
         let config = VirtioPmemConfig {
             start: addr.raw_value().to_le(),
             size: size.to_le(),
         };
 
+        let mut avail_features = 1u64 << VIRTIO_F_VERSION_1;
+
+        if iommu {
+            avail_features |= 1u64 << VIRTIO_F_IOMMU_PLATFORM;
+        }
+
         Ok(Pmem {
             kill_evt: None,
             disk: Some(disk),
-            avail_features: 1u64 << VIRTIO_F_VERSION_1,
+            avail_features,
             acked_features: 0u64,
             config,
             queue_evts: None,
diff --git a/vmm/src/device_manager.rs b/vmm/src/device_manager.rs
index 21029fdb5..5120cfdbc 100644
--- a/vmm/src/device_manager.rs
+++ b/vmm/src/device_manager.rs
@@ -789,7 +789,7 @@ impl DeviceManager {
                 *mem_slots += 1;
 
                 let virtio_pmem_device =
-                    vm_virtio::Pmem::new(file, pmem_guest_addr, size as GuestUsize)
+                    vm_virtio::Pmem::new(file, pmem_guest_addr, size as GuestUsize, false)
                         .map_err(DeviceManagerError::CreateVirtioPmem)?;
 
                 devices.push(Box::new(virtio_pmem_device) as Box<dyn vm_virtio::VirtioDevice>);