This patch pre-heat vhost iotlb cache when passthrough mode enabled.
Sometimes, even if user specified iommu_platform for vhost devices,
IOMMU might still be disabled. One case is passthrough mode in VT-d
implementation. We can detect this by observing iommu_list. If it's
empty, it means IOMMU translation is disabled, then we can actually
pre-heat the translation (it'll be static mapping then) by first
invalidating all IOTLB, then cache existing memory ranges into vhost
backend iotlb using 1:1 mapping.
Signed-off-by: Peter Xu <pet...@redhat.com>
---
hw/virtio/trace-events | 4 ++++
hw/virtio/vhost.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 53 insertions(+)
diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
index 1f7a7c1..54dcbb3 100644
--- a/hw/virtio/trace-events
+++ b/hw/virtio/trace-events
@@ -24,3 +24,7 @@ virtio_balloon_handle_output(const char *name, uint64_t gpa)
"section name: %s g
virtio_balloon_get_config(uint32_t num_pages, uint32_t actual) "num_pages: %d
actual: %d"
virtio_balloon_set_config(uint32_t actual, uint32_t oldactual) "actual: %d
oldactual: %d"
virtio_balloon_to_target(uint64_t target, uint32_t num_pages) "balloon target:
%"PRIx64" num_pages: %d"
+
+# hw/virtio/vhost.c
+vhost_iommu_commit(void) ""
+vhost_iommu_static_preheat(void) ""
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 03a46a7..8069135 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -27,6 +27,7 @@
#include "hw/virtio/virtio-access.h"
#include "migration/blocker.h"
#include "sysemu/dma.h"
+#include "trace.h"
/* enabled until disconnected backend stabilizes */
#define _VHOST_DEBUG 1
@@ -730,6 +731,11 @@ static void vhost_iommu_unmap_notify(IOMMUNotifier *n,
IOMMUTLBEntry *iotlb)
}
}
+static bool vhost_iommu_mr_enabled(struct vhost_dev *dev)
+{
+ return !QLIST_EMPTY(&dev->iommu_list);
+}
+
static void vhost_iommu_region_add(MemoryListener *listener,
MemoryRegionSection *section)
{
@@ -782,6 +788,48 @@ static void vhost_iommu_region_del(MemoryListener
*listener,
}
}
+static void vhost_iommu_commit(MemoryListener *listener)
+{
+ struct vhost_dev *dev = container_of(listener, struct vhost_dev,
+ iommu_listener);
+ struct vhost_memory_region *r;
+ int i;
+
+ trace_vhost_iommu_commit();
+
+ if (!vhost_iommu_mr_enabled(dev)) {
+ /*
+ * This means iommu_platform is enabled, however iommu memory
+ * region is disabled, e.g., when device passthrough is setup.
+ * Then, no translation is needed any more.
+ *
+ * Let's first invalidate the whole IOTLB, then pre-heat the
+ * static mapping by looping over vhost memory ranges.
+ */
+
+ if (dev->vhost_ops->vhost_invalidate_device_iotlb(dev, 0,
+ UINT64_MAX)) {
+ error_report("%s: flush existing IOTLB failed", __func__);
+ return;
+ }
+
+ for (i = 0; i < dev->mem->nregions; i++) {
+ r = &dev->mem->regions[i];
+ /* Vhost regions are writable RAM, so IOMMU_RW suites. */
+ if (dev->vhost_ops->vhost_update_device_iotlb(dev,
+ r->guest_phys_addr,
+ r->userspace_addr,
+ r->memory_size,
+ IOMMU_RW)) {
+ error_report("%s: pre-heat static mapping failed", __func__);
+ return;
+ }
+ }
+
+ trace_vhost_iommu_static_preheat();
+ }
+}
+
static void vhost_region_nop(MemoryListener *listener,
MemoryRegionSection *section)
{
@@ -1298,6 +1346,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
hdev->iommu_listener = (MemoryListener) {
.region_add = vhost_iommu_region_add,
.region_del = vhost_iommu_region_del,
+ .commit = vhost_iommu_commit,
};
if (hdev->migration_blocker == NULL) {
--
2.7.4
