Re: [PATCH V4 12/43] vfio/container: restore DMA vaddr
On 5/29/25 21:24, Steve Sistare wrote:
In new QEMU, do not register the memory listener at device creation time.
Register it later, in the container post_load handler, after all vmstate
that may affect regions and mapping boundaries has been loaded. The
post_load registration will cause the listener to invoke its callback on
each flat section, and the calls will match the mappings remembered by the
kernel.
The listener calls a special dma_map handler that passes the new VA of each
section to the kernel using VFIO_DMA_MAP_FLAG_VADDR. Restore the normal
handler at the end.
Signed-off-by: Steve Sistare
Reviewed-by: Cédric Le Goater
Thanks,
C.
---
include/hw/vfio/vfio-cpr.h | 3 +++
hw/vfio/container.c| 15 ++--
hw/vfio/cpr-legacy.c | 57 ++
3 files changed, 73 insertions(+), 2 deletions(-)
diff --git a/include/hw/vfio/vfio-cpr.h b/include/hw/vfio/vfio-cpr.h
index 5a2e5f6..0462447 100644
--- a/include/hw/vfio/vfio-cpr.h
+++ b/include/hw/vfio/vfio-cpr.h
@@ -17,6 +17,9 @@ struct VFIOGroup;
typedef struct VFIOContainerCPR {
Error *blocker;
+int (*saved_dma_map)(const struct VFIOContainerBase *bcontainer,
+ hwaddr iova, ram_addr_t size,
+ void *vaddr, bool readonly, MemoryRegion *mr);
} VFIOContainerCPR;
diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index 798abda..f91f2d5 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -137,6 +137,8 @@ static int vfio_legacy_dma_unmap_one(const
VFIOContainerBase *bcontainer,
int ret;
Error *local_err = NULL;
+g_assert(!cpr_is_incoming());
+
if (iotlb && vfio_container_dirty_tracking_is_started(bcontainer)) {
if (!vfio_container_devices_dirty_tracking_is_supported(bcontainer) &&
bcontainer->dirty_pages_supported) {
@@ -691,8 +693,17 @@ static bool vfio_container_connect(VFIOGroup *group,
AddressSpace *as,
}
group_was_added = true;
-if (!vfio_listener_register(bcontainer, errp)) {
-goto fail;
+/*
+ * If CPR, register the listener later, after all state that may
+ * affect regions and mapping boundaries has been cpr load'ed. Later,
+ * the listener will invoke its callback on each flat section and call
+ * dma_map to supply the new vaddr, and the calls will match the mappings
+ * remembered by the kernel.
+ */
+if (!cpr_is_incoming()) {
+if (!vfio_listener_register(bcontainer, errp)) {
+goto fail;
+}
}
bcontainer->initialized = true;
diff --git a/hw/vfio/cpr-legacy.c b/hw/vfio/cpr-legacy.c
index cf80332..512ef41 100644
--- a/hw/vfio/cpr-legacy.c
+++ b/hw/vfio/cpr-legacy.c
@@ -10,11 +10,13 @@
#include "hw/vfio/vfio-container.h"
#include "hw/vfio/vfio-cpr.h"
#include "hw/vfio/vfio-device.h"
+#include "hw/vfio/vfio-listener.h"
#include "migration/blocker.h"
#include "migration/cpr.h"
#include "migration/migration.h"
#include "migration/vmstate.h"
#include "qapi/error.h"
+#include "qemu/error-report.h"
static bool vfio_dma_unmap_vaddr_all(VFIOContainer *container, Error **errp)
{
@@ -31,6 +33,32 @@ static bool vfio_dma_unmap_vaddr_all(VFIOContainer
*container, Error **errp)
return true;
}
+/*
+ * Set the new @vaddr for any mappings registered during cpr load.
+ * The incoming state is cleared thereafter.
+ */
+static int vfio_legacy_cpr_dma_map(const VFIOContainerBase *bcontainer,
+ hwaddr iova, ram_addr_t size, void *vaddr,
+ bool readonly, MemoryRegion *mr)
+{
+const VFIOContainer *container = container_of(bcontainer, VFIOContainer,
+ bcontainer);
+struct vfio_iommu_type1_dma_map map = {
+.argsz = sizeof(map),
+.flags = VFIO_DMA_MAP_FLAG_VADDR,
+.vaddr = (__u64)(uintptr_t)vaddr,
+.iova = iova,
+.size = size,
+};
+
+g_assert(cpr_is_incoming());
+
+if (ioctl(container->fd, VFIO_IOMMU_MAP_DMA, &map)) {
+return -errno;
+}
+
+return 0;
+}
static bool vfio_cpr_supported(VFIOContainer *container, Error **errp)
{
@@ -59,11 +87,34 @@ static int vfio_container_pre_save(void *opaque)
return 0;
}
+static int vfio_container_post_load(void *opaque, int version_id)
+{
+VFIOContainer *container = opaque;
+VFIOContainerBase *bcontainer = &container->bcontainer;
+VFIOGroup *group;
+Error *local_err = NULL;
+
+if (!vfio_listener_register(bcontainer, &local_err)) {
+error_report_err(local_err);
+return -1;
+}
+
+QLIST_FOREACH(group, &container->group_list, container_next) {
+VFIOIOMMUClass *vioc = VFIO_IOMMU_GET_CLASS(bcontainer);
+
+/* Restore original dma_map function */
+vioc->dma_map = container->cpr.saved_dma_map;
+}
+return 0;
+}
+
static
[PATCH V4 12/43] vfio/container: restore DMA vaddr
In new QEMU, do not register the memory listener at device creation time.
Register it later, in the container post_load handler, after all vmstate
that may affect regions and mapping boundaries has been loaded. The
post_load registration will cause the listener to invoke its callback on
each flat section, and the calls will match the mappings remembered by the
kernel.
The listener calls a special dma_map handler that passes the new VA of each
section to the kernel using VFIO_DMA_MAP_FLAG_VADDR. Restore the normal
handler at the end.
Signed-off-by: Steve Sistare
---
include/hw/vfio/vfio-cpr.h | 3 +++
hw/vfio/container.c| 15 ++--
hw/vfio/cpr-legacy.c | 57 ++
3 files changed, 73 insertions(+), 2 deletions(-)
diff --git a/include/hw/vfio/vfio-cpr.h b/include/hw/vfio/vfio-cpr.h
index 5a2e5f6..0462447 100644
--- a/include/hw/vfio/vfio-cpr.h
+++ b/include/hw/vfio/vfio-cpr.h
@@ -17,6 +17,9 @@ struct VFIOGroup;
typedef struct VFIOContainerCPR {
Error *blocker;
+int (*saved_dma_map)(const struct VFIOContainerBase *bcontainer,
+ hwaddr iova, ram_addr_t size,
+ void *vaddr, bool readonly, MemoryRegion *mr);
} VFIOContainerCPR;
diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index 798abda..f91f2d5 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -137,6 +137,8 @@ static int vfio_legacy_dma_unmap_one(const
VFIOContainerBase *bcontainer,
int ret;
Error *local_err = NULL;
+g_assert(!cpr_is_incoming());
+
if (iotlb && vfio_container_dirty_tracking_is_started(bcontainer)) {
if (!vfio_container_devices_dirty_tracking_is_supported(bcontainer) &&
bcontainer->dirty_pages_supported) {
@@ -691,8 +693,17 @@ static bool vfio_container_connect(VFIOGroup *group,
AddressSpace *as,
}
group_was_added = true;
-if (!vfio_listener_register(bcontainer, errp)) {
-goto fail;
+/*
+ * If CPR, register the listener later, after all state that may
+ * affect regions and mapping boundaries has been cpr load'ed. Later,
+ * the listener will invoke its callback on each flat section and call
+ * dma_map to supply the new vaddr, and the calls will match the mappings
+ * remembered by the kernel.
+ */
+if (!cpr_is_incoming()) {
+if (!vfio_listener_register(bcontainer, errp)) {
+goto fail;
+}
}
bcontainer->initialized = true;
diff --git a/hw/vfio/cpr-legacy.c b/hw/vfio/cpr-legacy.c
index cf80332..512ef41 100644
--- a/hw/vfio/cpr-legacy.c
+++ b/hw/vfio/cpr-legacy.c
@@ -10,11 +10,13 @@
#include "hw/vfio/vfio-container.h"
#include "hw/vfio/vfio-cpr.h"
#include "hw/vfio/vfio-device.h"
+#include "hw/vfio/vfio-listener.h"
#include "migration/blocker.h"
#include "migration/cpr.h"
#include "migration/migration.h"
#include "migration/vmstate.h"
#include "qapi/error.h"
+#include "qemu/error-report.h"
static bool vfio_dma_unmap_vaddr_all(VFIOContainer *container, Error **errp)
{
@@ -31,6 +33,32 @@ static bool vfio_dma_unmap_vaddr_all(VFIOContainer
*container, Error **errp)
return true;
}
+/*
+ * Set the new @vaddr for any mappings registered during cpr load.
+ * The incoming state is cleared thereafter.
+ */
+static int vfio_legacy_cpr_dma_map(const VFIOContainerBase *bcontainer,
+ hwaddr iova, ram_addr_t size, void *vaddr,
+ bool readonly, MemoryRegion *mr)
+{
+const VFIOContainer *container = container_of(bcontainer, VFIOContainer,
+ bcontainer);
+struct vfio_iommu_type1_dma_map map = {
+.argsz = sizeof(map),
+.flags = VFIO_DMA_MAP_FLAG_VADDR,
+.vaddr = (__u64)(uintptr_t)vaddr,
+.iova = iova,
+.size = size,
+};
+
+g_assert(cpr_is_incoming());
+
+if (ioctl(container->fd, VFIO_IOMMU_MAP_DMA, &map)) {
+return -errno;
+}
+
+return 0;
+}
static bool vfio_cpr_supported(VFIOContainer *container, Error **errp)
{
@@ -59,11 +87,34 @@ static int vfio_container_pre_save(void *opaque)
return 0;
}
+static int vfio_container_post_load(void *opaque, int version_id)
+{
+VFIOContainer *container = opaque;
+VFIOContainerBase *bcontainer = &container->bcontainer;
+VFIOGroup *group;
+Error *local_err = NULL;
+
+if (!vfio_listener_register(bcontainer, &local_err)) {
+error_report_err(local_err);
+return -1;
+}
+
+QLIST_FOREACH(group, &container->group_list, container_next) {
+VFIOIOMMUClass *vioc = VFIO_IOMMU_GET_CLASS(bcontainer);
+
+/* Restore original dma_map function */
+vioc->dma_map = container->cpr.saved_dma_map;
+}
+return 0;
+}
+
static const VMStateDescription vfio_container_vmstate = {
.name = "vfio-container",
.version_id = 0,
.minimum_version_id = 0,
+
