stratovirt/vfio-fix-the-problem-of-dma-mapping-failed.patch

From 023dde42b55a58c7a41293566e95a0fc94efa2c6 Mon Sep 17 00:00:00 2001
From: "Xinle.Guo" <guoxinle1@huawei.com>
Date: Thu, 19 Aug 2021 20:48:25 +0800
Subject: [PATCH 7/8] vfio: fix the problem of dma mapping failed

Failed to use libvirt to manager more than two vfio devices.
The reason is that creating a container for every vfio device,
the process stratovirt uses more than the memory locked limit.

Signed-off-by: Xinle.Guo <guoxinle1@huawei.com>
---
 machine/src/lib.rs   | 24 +++++++++++-------------
 vfio/src/vfio_dev.rs | 25 +++++++++++++++----------
 vfio/src/vfio_pci.rs | 31 ++++++++++++++++++-------------
 3 files changed, 44 insertions(+), 36 deletions(-)

diff --git a/machine/src/lib.rs b/machine/src/lib.rs
index 9eb3039..8ba0ba3 100644
--- a/machine/src/lib.rs
+++ b/machine/src/lib.rs
@@ -121,7 +121,7 @@ use devices::legacy::FwCfgOps;
 #[cfg(target_arch = "aarch64")]
 use devices::InterruptController;
 use hypervisor::KVM_FDS;
-use kvm_ioctls::{DeviceFd, VcpuFd};
+use kvm_ioctls::VcpuFd;
 use machine_manager::config::{
     get_pci_bdf, parse_balloon, parse_blk, parse_net, parse_rng_dev, parse_root_port, parse_vfio,
     parse_virtconsole, parse_virtio_serial, parse_vsock, MachineMemConfig, PFlashConfig, PciBdf,
@@ -132,7 +132,7 @@ use machine_manager::machine::{KvmVmState, MachineInterface};
 use migration::MigrationManager;
 use util::loop_context::{EventNotifier, NotifierCallback, NotifierOperation};
 use util::seccomp::{BpfRule, SeccompOpt, SyscallFilter};
-use vfio::vfio_pci::create_vfio_device;
+use vfio::vfio_pci::create_vfio_container;
 use vfio::{VfioContainer, VfioPciDevice};
 use virtio::{balloon_allow_list, Balloon, Block, Console, Rng, VirtioMmioDevice, VirtioPciDevice};
 use vmm_sys_util::epoll::EventSet;
@@ -478,13 +478,8 @@ pub trait MachineOps {
         &mut self,
         vm_config: &VmConfig,
         cfg_args: &str,
-        dev_fd: Arc<DeviceFd>,
+        container: Arc<VfioContainer>,
     ) -> Result<()> {
-        let sys_mem = self.get_sys_mem().clone();
-        let container = Arc::new(
-            VfioContainer::new(dev_fd, &sys_mem).chain_err(|| "Failed to create vfio container")?,
-        );
-
         let device_cfg: VfioConfig = parse_vfio(vm_config, cfg_args)?;
         let path = "/sys/bus/pci/devices/".to_string() + &device_cfg.host;
         let name = device_cfg.id;
@@ -543,10 +538,7 @@ pub trait MachineOps {
                 .chain_err(|| ErrorKind::AddDevErr("pflash".to_string()))?;
         }
 
-        // Create an emulated kvm device that is used for VFIO. It should be created only once.
-        // See the kernel docs for `KVM_CREATE_DEVICE` to get more info.
-        let vfio_dev = create_vfio_device().chain_err(|| "Failed to create kvm device for VFIO")?;
-
+        let mut container: Option<Arc<VfioContainer>> = None;
         for dev in &cloned_vm_config.devices {
             let cfg_args = dev.1.as_str();
             match dev.0.as_str() {
@@ -581,7 +573,13 @@ pub trait MachineOps {
                     self.add_virtio_rng(vm_config, cfg_args)?;
                 }
                 "vfio-pci" => {
-                    self.add_vfio_device(&vm_config, cfg_args, vfio_dev.clone())?;
+                    if container.is_none() {
+                        container = Some(
+                            create_vfio_container(self.get_sys_mem().clone())
+                                .chain_err(|| "Failed to create vfio container")?,
+                        );
+                    }
+                    self.add_vfio_device(&vm_config, cfg_args, container.clone().unwrap())?;
                 }
                 _ => {
                     bail!("Unsupported device: {:?}", dev.0.as_str());
diff --git a/vfio/src/vfio_dev.rs b/vfio/src/vfio_dev.rs
index 30f7d5a..93922ba 100644
--- a/vfio/src/vfio_dev.rs
+++ b/vfio/src/vfio_dev.rs
@@ -96,8 +96,8 @@ pub struct VfioMemoryRegion {
     pub memory_size: u64,
     // Host virtual address.
     pub userspace_addr: u64,
-    // No flags specified for now.
-    flags_padding: u64,
+    // IOMMU mapped flag.
+    pub iommu_mapped: bool,
 }
 
 /// `VfioMemInfo` structure contains pinning pages information. If any pages need to be zapped from
@@ -131,7 +131,7 @@ impl VfioMemInfo {
             guest_phys_addr,
             memory_size,
             userspace_addr,
-            flags_padding: 0_u64,
+            iommu_mapped: false,
         });
 
         Ok(())
@@ -150,7 +150,7 @@ impl VfioMemInfo {
             guest_phys_addr: fr.addr_range.base.raw_value(),
             memory_size: fr.addr_range.size,
             userspace_addr: hva + fr.offset_in_region,
-            flags_padding: 0_u64,
+            iommu_mapped: false,
         };
         let mut mem_regions = self.regions.lock().unwrap();
         for (index, mr) in mem_regions.iter().enumerate() {
@@ -378,9 +378,11 @@ impl VfioGroup {
             return Err(ErrorKind::VfioIoctl("VFIO_GROUP_SET_CONTAINER".to_string(), ret).into());
         }
 
-        if let Err(e) = container.set_iommu(vfio::VFIO_TYPE1v2_IOMMU) {
-            unsafe { ioctl_with_ref(&self.group, VFIO_GROUP_UNSET_CONTAINER(), &raw_fd) };
-            return Err(e).chain_err(|| "Failed to set IOMMU");
+        if container.groups.lock().unwrap().is_empty() {
+            if let Err(e) = container.set_iommu(vfio::VFIO_TYPE1v2_IOMMU) {
+                unsafe { ioctl_with_ref(&self.group, VFIO_GROUP_UNSET_CONTAINER(), &raw_fd) };
+                return Err(e).chain_err(|| "Failed to set IOMMU");
+            }
         }
 
         if let Err(e) = container.kvm_device_add_group(&self.group.as_raw_fd()) {
@@ -473,15 +475,18 @@ impl VfioDevice {
             group_id = n.parse::<u32>().chain_err(|| "Invalid iommu group id")?;
         }
 
-        let mut groups = container.groups.lock().unwrap();
-        if let Some(g) = groups.get(&group_id) {
+        if let Some(g) = container.groups.lock().unwrap().get(&group_id) {
             return Ok(g.clone());
         }
         let group = Arc::new(VfioGroup::new(group_id)?);
         group
             .connect_container(&container)
             .chain_err(|| "Fail to connect container")?;
-        groups.insert(group_id, group.clone());
+        container
+            .groups
+            .lock()
+            .unwrap()
+            .insert(group_id, group.clone());
 
         Ok(group)
     }
diff --git a/vfio/src/vfio_pci.rs b/vfio/src/vfio_pci.rs
index 5cc674a..7bec445 100644
--- a/vfio/src/vfio_pci.rs
+++ b/vfio/src/vfio_pci.rs
@@ -19,13 +19,12 @@ use std::sync::{Arc, Mutex, Weak};
 use byteorder::{ByteOrder, LittleEndian};
 use error_chain::ChainedError;
 use kvm_bindings::{kvm_create_device, kvm_device_type_KVM_DEV_TYPE_VFIO};
-use kvm_ioctls::DeviceFd;
 use vfio_bindings::bindings::vfio;
 use vmm_sys_util::eventfd::EventFd;
 use vmm_sys_util::ioctl::ioctl_with_mut_ref;
 
 use super::errors::{ErrorKind, Result, ResultExt};
-use address_space::{FileBackend, GuestAddress, HostMemMapping, Region, RegionOps};
+use address_space::{AddressSpace, FileBackend, GuestAddress, HostMemMapping, Region, RegionOps};
 use hypervisor::{MsiVector, KVM_FDS};
 #[cfg(target_arch = "aarch64")]
 use pci::config::SECONDARY_BUS_NUM;
@@ -380,7 +379,7 @@ impl VfioPciDevice {
                 .register_bar(i as usize, bar_region, vfio_bar.region_type, false, size);
         }
 
-        self.map_guest_memory()?;
+        self.do_dma_map()?;
 
         Ok(())
     }
@@ -569,14 +568,17 @@ impl VfioPciDevice {
     }
 
     /// Add all guest memory regions into IOMMU table.
-    fn map_guest_memory(&mut self) -> Result<()> {
+    fn do_dma_map(&mut self) -> Result<()> {
         let container = &self.vfio_device.container;
-        let regions = container.vfio_mem_info.regions.lock().unwrap();
-
-        for r in regions.iter() {
-            container
-                .vfio_dma_map(r.guest_phys_addr, r.memory_size, r.userspace_addr)
-                .chain_err(|| "Failed to add guest memory region map into IOMMU table")?;
+        let mut regions = container.vfio_mem_info.regions.lock().unwrap();
+
+        for r in regions.iter_mut() {
+            if !r.iommu_mapped {
+                container
+                    .vfio_dma_map(r.guest_phys_addr, r.memory_size, r.userspace_addr)
+                    .chain_err(|| "Failed to add guest memory region map into IOMMU table")?;
+                r.iommu_mapped = true;
+            }
         }
         Ok(())
     }
@@ -872,7 +874,7 @@ fn get_irq_rawfds(gsi_msi_routes: &[GsiMsiRoute]) -> Vec<RawFd> {
     rawfds
 }
 
-pub fn create_vfio_device() -> Result<Arc<DeviceFd>> {
+pub fn create_vfio_container(sys_mem: Arc<AddressSpace>) -> Result<Arc<VfioContainer>> {
     let mut vfio_device = kvm_create_device {
         type_: kvm_device_type_KVM_DEV_TYPE_VFIO,
         fd: 0,
@@ -884,7 +886,10 @@ pub fn create_vfio_device() -> Result<Arc<DeviceFd>> {
         .as_ref()
         .unwrap()
         .create_device(&mut vfio_device)
-        .chain_err(|| "Failed to create VFIO type KVM device")?;
+        .chain_err(|| "Failed to create kvm device for VFIO")?;
 
-    Ok(Arc::new(dev_fd))
+    Ok(Arc::new(
+        VfioContainer::new(Arc::new(dev_fd), &sys_mem)
+            .chain_err(|| "Failed to create vfio container")?,
+    ))
 }
-- 
2.25.1