This makes use of the new "memory registering" feature. The idea is
to provide the userspace ability to notify the host kernel about pages
which are going to be used for DMA. Having this information, the host
kernel can pin them all once per user process, do locked pages
accounting (once) and not spent time on doing that in real time with
possible failures which cannot be handled nicely in some cases.
This adds a prereg memory listener which listens on address_space_memory
and notifies a VFIO container about memory which needs to be
pinned/unpinned. VFIO MMIO regions (i.e. "skip dump" regions) are skipped.
As there is no per-IOMMU-type release() callback anymore, this stores
the IOMMU type in the container so vfio_listener_release() can determine
if it needs to unregister @prereg_listener.
The feature is only enabled for SPAPR IOMMU v2. The host kernel changes
are required. Since v2 does not need/support VFIO_IOMMU_ENABLE, this does
not call it when v2 is detected and enabled.
This enforces guest RAM blocks to be host page size aligned; however
this is not new as KVM already requires memory slots to be host page
size aligned.
Signed-off-by: Alexey Kardashevskiy <address@hidden>
---
Changes:
v16:
* switched to 64bit math everywhere as there is no chance to see
region_add on RAM blocks even remotely close to 1<<64bytes.
v15:
* banned unaligned sections
* added an vfio_prereg_gpa_to_ua() helper
v14:
* s/free_container_exit/listener_release_exit/g
* added "if memory_region_is_iommu()" to vfio_prereg_listener_skipped_section
---
hw/vfio/Makefile.objs | 1 +
hw/vfio/common.c | 38 +++++++++---
hw/vfio/prereg.c | 137 ++++++++++++++++++++++++++++++++++++++++++
include/hw/vfio/vfio-common.h | 4 ++
trace-events | 2 +
5 files changed, 172 insertions(+), 10 deletions(-)
create mode 100644 hw/vfio/prereg.c
diff --git a/hw/vfio/Makefile.objs b/hw/vfio/Makefile.objs
index ceddbb8..5800e0e 100644
--- a/hw/vfio/Makefile.objs
+++ b/hw/vfio/Makefile.objs
@@ -4,4 +4,5 @@ obj-$(CONFIG_PCI) += pci.o pci-quirks.o
obj-$(CONFIG_SOFTMMU) += platform.o
obj-$(CONFIG_SOFTMMU) += calxeda-xgmac.o
obj-$(CONFIG_SOFTMMU) += amd-xgbe.o
+obj-$(CONFIG_SOFTMMU) += prereg.o
endif
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 2050040..496eb82 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -501,6 +501,9 @@ static const MemoryListener vfio_memory_listener = {
static void vfio_listener_release(VFIOContainer *container)
{
memory_listener_unregister(&container->listener);
+ if (container->iommu_type == VFIO_SPAPR_TCE_v2_IOMMU) {
+ memory_listener_unregister(&container->prereg_listener);
+ }
}
int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
@@ -808,8 +811,8 @@ static int vfio_connect_container(VFIOGroup *group,
AddressSpace *as)
goto free_container_exit;
}
- ret = ioctl(fd, VFIO_SET_IOMMU,
- v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU);
+ container->iommu_type = v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU;
+ ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type);
if (ret) {
error_report("vfio: failed to set iommu for container: %m");
ret = -errno;
@@ -834,8 +837,10 @@ static int vfio_connect_container(VFIOGroup *group,
AddressSpace *as)
if ((ret == 0) && (info.flags & VFIO_IOMMU_INFO_PGSIZES)) {
container->iova_pgsizes = info.iova_pgsizes;
}
- } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU)) {
+ } 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;
+ bool v2 = !!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_IOMMU);
ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
if (ret) {
@@ -843,7 +848,9 @@ static int vfio_connect_container(VFIOGroup *group,
AddressSpace *as)
ret = -errno;
goto free_container_exit;
}
- ret = ioctl(fd, VFIO_SET_IOMMU, VFIO_SPAPR_TCE_IOMMU);
+ container->iommu_type =
+ v2 ? VFIO_SPAPR_TCE_v2_IOMMU : VFIO_SPAPR_TCE_IOMMU;
+ ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type);
if (ret) {
error_report("vfio: failed to set iommu for container: %m");
ret = -errno;
@@ -855,11 +862,22 @@ static int vfio_connect_container(VFIOGroup *group,
AddressSpace *as)
* when container fd is closed so we do not call it explicitly
* in this file.
*/
- ret = ioctl(fd, VFIO_IOMMU_ENABLE);
- if (ret) {
- error_report("vfio: failed to enable container: %m");
- ret = -errno;
- goto free_container_exit;
+ if (!v2) {
+ ret = ioctl(fd, VFIO_IOMMU_ENABLE);
+ if (ret) {
+ error_report("vfio: failed to enable container: %m");
+ ret = -errno;
+ goto free_container_exit;
+ }
+ } else {
+ container->prereg_listener = vfio_prereg_listener;
+
+ memory_listener_register(&container->prereg_listener,
+ &address_space_memory);
+ if (container->error) {
+ error_report("vfio: RAM memory listener initialization failed for
container");
+ goto listener_release_exit;
+ }
}
/*
@@ -872,7 +890,7 @@ static int vfio_connect_container(VFIOGroup *group,
AddressSpace *as)
if (ret) {
error_report("vfio: VFIO_IOMMU_SPAPR_TCE_GET_INFO failed: %m");
ret = -errno;
- goto free_container_exit;
+ goto listener_release_exit;
}
container->min_iova = info.dma32_window_start;
container->max_iova = container->min_iova + info.dma32_window_size - 1;
diff --git a/hw/vfio/prereg.c b/hw/vfio/prereg.c
new file mode 100644
index 0000000..d0e4728
--- /dev/null
+++ b/hw/vfio/prereg.c
@@ -0,0 +1,137 @@
+/*
+ * DMA memory preregistration
+ *
+ * Authors:
+ * Alexey Kardashevskiy <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include <sys/ioctl.h>
+#include <linux/vfio.h>
+
+#include "hw/vfio/vfio-common.h"
+#include "hw/hw.h"
+#include "qemu/error-report.h"
+#include "trace.h"
+
+static bool vfio_prereg_listener_skipped_section(MemoryRegionSection *section)
+{
+ if (memory_region_is_iommu(section->mr)) {
+ error_report("Cannot possibly preregister IOMMU memory");