[PATCH RFCv2 6/8] backends/iommufd: Add ability to disable hugepages

[Joao Martins <joao.m.martins@oracle.com>]

Allow disabling hugepages to be dirty track at base page
granularity in similar vein to vfio_type1_iommu.disable_hugepages
but per IOAS.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
 backends/iommufd.c       | 36 ++++++++++++++++++++++++++++++++++++
 backends/trace-events    |  1 +
 hw/vfio/iommufd.c        |  4 ++++
 include/sysemu/iommufd.h |  4 ++++
 qapi/qom.json            |  2 +-
 5 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/backends/iommufd.c b/backends/iommufd.c
index dd676d493c37..72fd98a9a50c 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -29,6 +29,7 @@ static void iommufd_backend_init(Object *obj)
     be->fd = -1;
     be->users = 0;
     be->owned = true;
+    be->hugepages = 1;
 }
 
 static void iommufd_backend_finalize(Object *obj)
@@ -63,6 +64,14 @@ static bool iommufd_backend_can_be_deleted(UserCreatable *uc)
     return !be->users;
 }
 
+static void iommufd_backend_set_hugepages(Object *obj, bool enabled,
+                                          Error **errp)
+{
+    IOMMUFDBackend *be = IOMMUFD_BACKEND(obj);
+
+    be->hugepages = enabled;
+}
+
 static void iommufd_backend_class_init(ObjectClass *oc, void *data)
 {
     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
@@ -70,6 +79,11 @@ static void iommufd_backend_class_init(ObjectClass *oc, void *data)
     ucc->can_be_deleted = iommufd_backend_can_be_deleted;
 
     object_class_property_add_str(oc, "fd", NULL, iommufd_backend_set_fd);
+
+    object_class_property_add_bool(oc, "hugepages", NULL,
+                                   iommufd_backend_set_hugepages);
+    object_class_property_set_description(oc, "hugepages",
+                                          "Set to 'off' to disable hugepages");
 }
 
 int iommufd_backend_connect(IOMMUFDBackend *be, Error **errp)
@@ -106,6 +120,28 @@ out:
     trace_iommufd_backend_disconnect(be->fd, be->users);
 }
 
+int iommufd_backend_set_option(int fd, uint32_t object_id,
+                               uint32_t option_id, uint64_t val64)
+{
+    int ret;
+    struct iommu_option option = {
+        .size = sizeof(option),
+        .option_id = option_id,
+        .op = IOMMU_OPTION_OP_SET,
+        .val64 = val64,
+        .object_id = object_id,
+    };
+
+    ret = ioctl(fd, IOMMU_OPTION, &option);
+    if (ret) {
+        error_report("Failed to set option %x to value %"PRIx64" %m", option_id,
+                     val64);
+    }
+    trace_iommufd_backend_set_option(fd, object_id, option_id, val64, ret);
+
+    return ret;
+}
+
 int iommufd_backend_alloc_ioas(IOMMUFDBackend *be, uint32_t *ioas_id,
                                Error **errp)
 {
diff --git a/backends/trace-events b/backends/trace-events
index 11a27cb114b6..076166552881 100644
--- a/backends/trace-events
+++ b/backends/trace-events
@@ -15,6 +15,7 @@ iommufd_backend_unmap_dma_non_exist(int iommufd, uint32_t ioas, uint64_t iova, u
 iommufd_backend_unmap_dma(int iommufd, uint32_t ioas, uint64_t iova, uint64_t size, int ret) " iommufd=%d ioas=%d iova=0x%"PRIx64" size=0x%"PRIx64" (%d)"
 iommufd_backend_alloc_hwpt(int iommufd, uint32_t dev_id, uint32_t pt_id, uint32_t flags, uint32_t hwpt_type, uint32_t len, uint64_t data_ptr, uint32_t out_hwpt_id, int ret) " iommufd=%d dev_id=%u pt_id=%u flags=0x%x hwpt_type=%u len=%u data_ptr=0x%"PRIx64" out_hwpt=%u (%d)"
 iommufd_backend_alloc_ioas(int iommufd, uint32_t ioas, int ret) " iommufd=%d ioas=%d (%d)"
+iommufd_backend_set_option(int iommufd, uint32_t object_id, uint32_t option_id, uint64_t val, int ret) " iommufd=%d object_id=%u option_id=%u val64=0x%"PRIx64" (%d)"
 iommufd_backend_free_id(int iommufd, uint32_t id, int ret) " iommufd=%d id=%d (%d)"
 iommufd_backend_set_dirty(int iommufd, uint32_t hwpt_id, bool start, int ret) " iommufd=%d hwpt=%d enable=%d (%d)"
 iommufd_backend_get_dirty_bitmap(int iommufd, uint32_t hwpt_id, uint64_t iova, uint64_t size, uint64_t page_size, int ret) " iommufd=%d hwpt=%d iova=0x%"PRIx64" size=0x%"PRIx64" page_size=0x%"PRIx64" (%d)"
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 79b13bd262cc..697d40841d7f 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -521,6 +521,10 @@ static int iommufd_cdev_attach(const char *name, VFIODevice *vbasedev,
         goto err_alloc_ioas;
     }
 
+    if (!vbasedev->iommufd_dev.iommufd->hugepages) {
+        iommufd_backend_set_option(vbasedev->iommufd_dev.iommufd->fd, ioas_id,
+                                   IOMMU_OPTION_HUGE_PAGES, 0);
+    }
     trace_iommufd_cdev_alloc_ioas(vbasedev->iommufd_dev.iommufd->fd, ioas_id);
 
     container = g_malloc0(sizeof(*container));
diff --git a/include/sysemu/iommufd.h b/include/sysemu/iommufd.h
index ba19b7ea4c19..bc6607e3d444 100644
--- a/include/sysemu/iommufd.h
+++ b/include/sysemu/iommufd.h
@@ -19,6 +19,7 @@ struct IOMMUFDBackend {
     /*< protected >*/
     int fd;            /* /dev/iommu file descriptor */
     bool owned;        /* is the /dev/iommu opened internally */
+    bool hugepages;    /* are hugepages enabled on the IOAS */
     uint32_t users;
 
     /*< public >*/
@@ -30,6 +31,9 @@ void iommufd_backend_disconnect(IOMMUFDBackend *be);
 int iommufd_backend_alloc_ioas(IOMMUFDBackend *be, uint32_t *ioas_id,
                                Error **errp);
 void iommufd_backend_free_id(IOMMUFDBackend *be, uint32_t id);
+int iommufd_backend_set_option(int fd, uint32_t object_id,
+                               uint32_t option_id,
+                               uint64_t val64);
 int iommufd_backend_map_dma(IOMMUFDBackend *be, uint32_t ioas_id, hwaddr iova,
                             ram_addr_t size, void *vaddr, bool readonly);
 int iommufd_backend_unmap_dma(IOMMUFDBackend *be, uint32_t ioas_id,
diff --git a/qapi/qom.json b/qapi/qom.json
index 84af23fe245d..9ad27e2b939b 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -809,7 +809,7 @@
 # Since: 9.0
 ##
 { 'struct': 'IOMMUFDProperties',
-  'data': { '*fd': 'str' } }
+  'data': { '*fd': 'str', '*hugepages': 'bool' } }
 
 ##
 # @RngProperties:
-- 
2.39.3