[Qemu-devel] [PATCH qemu v19 3/5] vfio: Add host side DMA window capabilities

[Alexey Kardashevskiy <aik@ozlabs.ru>]

There are going to be multiple IOMMUs per a container. This moves
the single host IOMMU parameter set to a list of VFIOHostDMAWindow.

This should cause no behavioral change and will be used later by
the SPAPR TCE IOMMU v2 which will also add a vfio_host_win_del() helper.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
Changes:
v18:
* vfio_host_win_add() checks for non-overlapping windows instead of calling
vfio_host_win_lookup() which checks for inclusion
* inlined vfio_host_win_lookup() as I ended up using it just once
* put VFIOHostDMAWindow::max_iova in new line in include/hw/vfio/vfio-common.h

v17:
* vfio_host_win_add() uses vfio_host_win_lookup() for overlap check and
aborts if any found instead of returning an error (as recovery is not
possible anyway)
* hw_error() when overlapped iommu is detected

v16:
* adjusted commit log with changes from v15

v15:
* s/vfio_host_iommu_add/vfio_host_win_add/
* s/VFIOHostIOMMU/VFIOHostDMAWindow/
---
 hw/vfio/common.c              | 60 +++++++++++++++++++++++++++++++------------
 include/hw/vfio/vfio-common.h | 10 ++++++--
 2 files changed, 52 insertions(+), 18 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 46381e6..7c8a531 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -28,6 +28,7 @@
 #include "exec/memory.h"
 #include "hw/hw.h"
 #include "qemu/error-report.h"
+#include "qemu/range.h"
 #include "sysemu/kvm.h"
 #ifdef CONFIG_KVM
 #include "linux/kvm.h"
@@ -241,6 +242,29 @@ static int vfio_dma_map(VFIOContainer *container, hwaddr iova,
     return -errno;
 }
 
+static void vfio_host_win_add(VFIOContainer *container,
+                              hwaddr min_iova, hwaddr max_iova,
+                              uint64_t iova_pgsizes)
+{
+    VFIOHostDMAWindow *hostwin;
+
+    QLIST_FOREACH(hostwin, &container->hostwin_list, hostwin_next) {
+        if (ranges_overlap(hostwin->min_iova,
+                           hostwin->max_iova - hostwin->min_iova + 1,
+                           min_iova,
+                           max_iova - min_iova + 1)) {
+            hw_error("%s: Overlapped IOMMU are not enabled", __func__);
+        }
+    }
+
+    hostwin = g_malloc0(sizeof(*hostwin));
+
+    hostwin->min_iova = min_iova;
+    hostwin->max_iova = max_iova;
+    hostwin->iova_pgsizes = iova_pgsizes;
+    QLIST_INSERT_HEAD(&container->hostwin_list, hostwin, hostwin_next);
+}
+
 static bool vfio_listener_skipped_section(MemoryRegionSection *section)
 {
     return (!memory_region_is_ram(section->mr) &&
@@ -329,6 +353,8 @@ static void vfio_listener_region_add(MemoryListener *listener,
     Int128 llend, llsize;
     void *vaddr;
     int ret;
+    VFIOHostDMAWindow *hostwin;
+    bool hostwin_found;
 
     if (vfio_listener_skipped_section(section)) {
         trace_vfio_listener_region_add_skip(
@@ -354,7 +380,15 @@ static void vfio_listener_region_add(MemoryListener *listener,
     }
     end = int128_get64(int128_sub(llend, int128_one()));
 
-    if ((iova < container->min_iova) || (end > container->max_iova)) {
+    hostwin_found = false;
+    QLIST_FOREACH(hostwin, &container->hostwin_list, hostwin_next) {
+        if (hostwin->min_iova <= iova && end <= hostwin->max_iova) {
+            hostwin_found = true;
+            break;
+        }
+    }
+
+    if (!hostwin_found) {
         error_report("vfio: IOMMU container %p can't map guest IOVA region"
                      " 0x%"HWADDR_PRIx"..0x%"HWADDR_PRIx,
                      container, iova, end);
@@ -369,10 +403,6 @@ static void vfio_listener_region_add(MemoryListener *listener,
 
         trace_vfio_listener_region_add_iommu(iova, end);
         /*
-         * FIXME: We should do some checking to see if the
-         * capabilities of the host VFIO IOMMU are adequate to model
-         * the guest IOMMU
-         *
          * FIXME: For VFIO iommu types which have KVM acceleration to
          * avoid bouncing all map/unmaps through qemu this way, this
          * would be the right place to wire that up (tell the KVM
@@ -879,17 +909,14 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as)
          * existing Type1 IOMMUs generally support any IOVA we're
          * going to actually try in practice.
          */
-        container->min_iova = 0;
-        container->max_iova = (hwaddr)-1;
-
-        /* Assume just 4K IOVA page size */
-        container->iova_pgsizes = 0x1000;
         info.argsz = sizeof(info);
         ret = ioctl(fd, VFIO_IOMMU_GET_INFO, &info);
         /* Ignore errors */
-        if ((ret == 0) && (info.flags & VFIO_IOMMU_INFO_PGSIZES)) {
-            container->iova_pgsizes = info.iova_pgsizes;
+        if (ret || !(info.flags & VFIO_IOMMU_INFO_PGSIZES)) {
+            /* Assume 4k IOVA page size */
+            info.iova_pgsizes = 4096;
         }
+        vfio_host_win_add(container, 0, (hwaddr)-1, info.iova_pgsizes);
     } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU) ||
                ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_IOMMU)) {
         struct vfio_iommu_spapr_tce_info info;
@@ -949,11 +976,12 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as)
             }
             goto free_container_exit;
         }
-        container->min_iova = info.dma32_window_start;
-        container->max_iova = container->min_iova + info.dma32_window_size - 1;
 
-        /* Assume just 4K IOVA pages for now */
-        container->iova_pgsizes = 0x1000;
+        /* The default table uses 4K pages */
+        vfio_host_win_add(container, info.dma32_window_start,
+                          info.dma32_window_start +
+                          info.dma32_window_size - 1,
+                          0x1000);
     } else {
         error_report("vfio: No available IOMMU models");
         ret = -EINVAL;
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 405c3b2..b1f3e92 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -82,9 +82,8 @@ typedef struct VFIOContainer {
      * contiguous IOVA window.  We may need to generalize that in
      * future
      */
-    hwaddr min_iova, max_iova;
-    uint64_t iova_pgsizes;
     QLIST_HEAD(, VFIOGuestIOMMU) giommu_list;
+    QLIST_HEAD(, VFIOHostDMAWindow) hostwin_list;
     QLIST_HEAD(, VFIOGroup) group_list;
     QLIST_ENTRY(VFIOContainer) next;
 } VFIOContainer;
@@ -97,6 +96,13 @@ typedef struct VFIOGuestIOMMU {
     QLIST_ENTRY(VFIOGuestIOMMU) giommu_next;
 } VFIOGuestIOMMU;
 
+typedef struct VFIOHostDMAWindow {
+    hwaddr min_iova;
+    hwaddr max_iova;
+    uint64_t iova_pgsizes;
+    QLIST_ENTRY(VFIOHostDMAWindow) hostwin_next;
+} VFIOHostDMAWindow;
+
 typedef struct VFIODeviceOps VFIODeviceOps;
 
 typedef struct VFIODevice {
-- 
2.5.0.rc3