[PATCH 03/16] util/vfio-helpers: Pass minimum page size to qemu_vfio_open_pci()

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

The block driver asks for a minimum page size, but it might not
match the minimum IOMMU requirement.
In the next commit qemu_vfio_init_pci() will be able to report
the minimum IOMMU page size back to the block driver.
In preparation, pass the minimum page size as argument to
qemu_vfio_open_pci().

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 include/qemu/vfio-helpers.h | 3 ++-
 block/nvme.c                | 5 +++--
 util/vfio-helpers.c         | 8 +++++++-
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/qemu/vfio-helpers.h b/include/qemu/vfio-helpers.h
index 4491c8e1a6e..5cb346d8e67 100644
--- a/include/qemu/vfio-helpers.h
+++ b/include/qemu/vfio-helpers.h
@@ -15,7 +15,8 @@
 
 typedef struct QEMUVFIOState QEMUVFIOState;
 
-QEMUVFIOState *qemu_vfio_open_pci(const char *device, Error **errp);
+QEMUVFIOState *qemu_vfio_open_pci(const char *device, size_t *min_page_size,
+                                  Error **errp);
 void qemu_vfio_close(QEMUVFIOState *s);
 int qemu_vfio_dma_map(QEMUVFIOState *s, void *host, size_t size,
                       bool temporary, uint64_t *iova_list);
diff --git a/block/nvme.c b/block/nvme.c
index 029694975b9..8335f5d70dd 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -690,6 +690,7 @@ static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
     uint64_t deadline, now;
     Error *local_err = NULL;
     volatile NvmeBar *regs = NULL;
+    size_t min_page_size = 4096;
 
     qemu_co_mutex_init(&s->dma_map_lock);
     qemu_co_queue_init(&s->dma_flush_queue);
@@ -702,7 +703,7 @@ static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
         return ret;
     }
 
-    s->vfio = qemu_vfio_open_pci(device, errp);
+    s->vfio = qemu_vfio_open_pci(device, &min_page_size, errp);
     if (!s->vfio) {
         ret = -EINVAL;
         goto out;
@@ -724,7 +725,7 @@ static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
         goto out;
     }
 
-    s->page_size = MAX(4096, 1u << (12 + NVME_CAP_MPSMIN(cap)));
+    s->page_size = MAX(min_page_size, 1u << (12 + NVME_CAP_MPSMIN(cap)));
     s->doorbell_scale = (4 << NVME_CAP_DSTRD(cap)) / sizeof(uint32_t);
     bs->bl.opt_mem_alignment = s->page_size;
     timeout_ms = MIN(500 * NVME_CAP_TO(cap), 30000);
diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c
index 14a549510fe..a2b084c69c1 100644
--- a/util/vfio-helpers.c
+++ b/util/vfio-helpers.c
@@ -488,8 +488,14 @@ static void qemu_vfio_open_common(QEMUVFIOState *s)
 
 /**
  * Open a PCI device, e.g. "0000:00:01.0".
+ *
+ * @min_page_size: Pointer holding the minimum page size requested
+ *
+ * If the IOMMU can not be configured with @min_page_size, the minimum
+ * page size is stored in @min_page_size and -EINVAL is returned.
  */
-QEMUVFIOState *qemu_vfio_open_pci(const char *device, Error **errp)
+QEMUVFIOState *qemu_vfio_open_pci(const char *device, size_t *min_page_size,
+                                  Error **errp)
 {
     int r;
     QEMUVFIOState *s = g_new0(QEMUVFIOState, 1);
-- 
2.26.2