On 2/19/25 15:48, John Levon wrote:
From: Jagannathan Raman <jag.ra...@oracle.com>

Instead of requesting region information on demand with
VFIO_DEVICE_GET_REGION_INFO, maintain a cache: this will become
necessary for performance for vfio-user, where this call becomes a
message over the control socket, so is of higher overhead than the
traditional path.

Originally-by: John Johnson <john.g.john...@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimts...@oracle.com>
Signed-off-by: Jagannathan Raman <jag.ra...@oracle.com>
Signed-off-by: John Levon <john.le...@nutanix.com>
---
  hw/vfio/ccw.c                 |  5 -----
  hw/vfio/common.c              | 12 ++++++++++++
  hw/vfio/container.c           | 10 ++++++++++
  hw/vfio/helpers.c             | 21 ++++++++++++++++-----
  hw/vfio/igd.c                 |  8 ++++----
  hw/vfio/pci.c                 |  8 ++++----
  include/hw/vfio/vfio-common.h |  1 +
  7 files changed, 47 insertions(+), 18 deletions(-)

diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
index 67bc137f9b..22378d50bc 100644
--- a/hw/vfio/ccw.c
+++ b/hw/vfio/ccw.c
@@ -510,7 +510,6 @@ static bool vfio_ccw_get_region(VFIOCCWDevice *vcdev, Error 
**errp)
vcdev->io_region_offset = info->offset;
      vcdev->io_region = g_malloc0(info->size);
-    g_free(info);
/* check for the optional async command region */
      ret = vfio_get_dev_region_info(vdev, VFIO_REGION_TYPE_CCW,
@@ -523,7 +522,6 @@ static bool vfio_ccw_get_region(VFIOCCWDevice *vcdev, Error 
**errp)
          }
          vcdev->async_cmd_region_offset = info->offset;
          vcdev->async_cmd_region = g_malloc0(info->size);
-        g_free(info);
      }
ret = vfio_get_dev_region_info(vdev, VFIO_REGION_TYPE_CCW,
@@ -536,7 +534,6 @@ static bool vfio_ccw_get_region(VFIOCCWDevice *vcdev, Error 
**errp)
          }
          vcdev->schib_region_offset = info->offset;
          vcdev->schib_region = g_malloc(info->size);
-        g_free(info);
      }
ret = vfio_get_dev_region_info(vdev, VFIO_REGION_TYPE_CCW,
@@ -550,7 +547,6 @@ static bool vfio_ccw_get_region(VFIOCCWDevice *vcdev, Error 
**errp)
          }
          vcdev->crw_region_offset = info->offset;
          vcdev->crw_region = g_malloc(info->size);
-        g_free(info);
      }
return true;
@@ -560,7 +556,6 @@ out_err:
      g_free(vcdev->schib_region);
      g_free(vcdev->async_cmd_region);
      g_free(vcdev->io_region);
-    g_free(info);
      return false;
  }
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 4434e0a0a2..1866b3d3c5 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -1569,6 +1569,16 @@ retry:
      return info;
  }
+static void vfio_get_all_regions(VFIODevice *vbasedev)
+{
+    struct vfio_region_info *info;
+    int i;
+
+    for (i = 0; i < vbasedev->num_regions; i++) {
+        vfio_get_region_info(vbasedev, i, &info);
+    }
+}
+
  void vfio_prepare_device(VFIODevice *vbasedev, VFIOContainerBase *bcontainer,
                           VFIOGroup *group, struct vfio_device_info *info)
  {
@@ -1586,6 +1596,8 @@ void vfio_prepare_device(VFIODevice *vbasedev, 
VFIOContainerBase *bcontainer,
      }
QLIST_INSERT_HEAD(&vfio_device_list, vbasedev, global_next);
+
+    vfio_get_all_regions(vbasedev);
  }
bool vfio_attach_device_by_iommu_type(const char *iommu_type, char *name,
diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index 37a3befbc5..36cd245c92 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -886,6 +886,16 @@ static bool vfio_get_device(VFIOGroup *group, const char 
*name,
static void vfio_put_base_device(VFIODevice *vbasedev)
  {
+    if (vbasedev->regions != NULL) {
+        int i;
+
+        for (i = 0; i < vbasedev->num_regions; i++) {
+            g_free(vbasedev->regions[i]);
+        }
+        g_free(vbasedev->regions);
+        vbasedev->regions = NULL;
+    }
+
      if (!vbasedev->group) {
          return;
      }
diff --git a/hw/vfio/helpers.c b/hw/vfio/helpers.c
index 4b255d4f3a..3c923d23b9 100644
--- a/hw/vfio/helpers.c
+++ b/hw/vfio/helpers.c
@@ -345,7 +345,7 @@ static int vfio_setup_region_sparse_mmaps(VFIORegion 
*region,
  int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
                        int index, const char *name)
  {
-    g_autofree struct vfio_region_info *info = NULL;
+    struct vfio_region_info *info = NULL;
      int ret;
ret = vfio_get_region_info(vbasedev, index, &info);
@@ -562,6 +562,17 @@ int vfio_get_region_info(VFIODevice *vbasedev, int index,
  {
      size_t argsz = sizeof(struct vfio_region_info);
+ /* create region cache */
+    if (vbasedev->regions == NULL) {
+        vbasedev->regions = g_new0(struct vfio_region_info *,
+                                   vbasedev->num_regions);
+    }
+    /* check cache */
+    if (vbasedev->regions[index] != NULL) {
+        *info = vbasedev->regions[index];
+        return 0;
+    }
+

why not populate vbasedev->regions[index] in vfio_get_all_regions() ?


Thanks,

C.



      *info = g_malloc0(argsz);
(*info)->index = index;
@@ -581,6 +592,9 @@ retry:
          goto retry;
      }
+ /* fill cache */
+    vbasedev->regions[index] = *info;
+
      return 0;
  }
@@ -599,7 +613,6 @@ int vfio_get_dev_region_info(VFIODevice *vbasedev, uint32_t type, hdr = vfio_get_region_info_cap(*info, VFIO_REGION_INFO_CAP_TYPE);
          if (!hdr) {
-            g_free(*info);
              continue;
          }
@@ -611,8 +624,6 @@ int vfio_get_dev_region_info(VFIODevice *vbasedev, uint32_t type,
          if (cap_type->type == type && cap_type->subtype == subtype) {
              return 0;
          }
-
-        g_free(*info);
      }
*info = NULL;
@@ -621,7 +632,7 @@ int vfio_get_dev_region_info(VFIODevice *vbasedev, uint32_t 
type,
bool vfio_has_region_cap(VFIODevice *vbasedev, int region, uint16_t cap_type)
  {
-    g_autofree struct vfio_region_info *info = NULL;
+    struct vfio_region_info *info = NULL;
      bool ret = false;
if (!vfio_get_region_info(vbasedev, region, &info)) {
diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c
index b1a237edd6..b5425ba9c0 100644
--- a/hw/vfio/igd.c
+++ b/hw/vfio/igd.c
@@ -490,10 +490,10 @@ void vfio_probe_igd_bar0_quirk(VFIOPCIDevice *vdev, int 
nr)
void vfio_probe_igd_bar4_quirk(VFIOPCIDevice *vdev, int nr)
  {
-    g_autofree struct vfio_region_info *rom = NULL;
-    g_autofree struct vfio_region_info *opregion = NULL;
-    g_autofree struct vfio_region_info *host = NULL;
-    g_autofree struct vfio_region_info *lpc = NULL;
+    struct vfio_region_info *rom = NULL;
+    struct vfio_region_info *opregion = NULL;
+    struct vfio_region_info *host = NULL;
+    struct vfio_region_info *lpc = NULL;
      VFIOQuirk *quirk;
      VFIOIGDQuirk *igd;
      PCIDevice *lpc_bridge;
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 83fe329474..a4f99fc5e0 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -879,7 +879,7 @@ static void vfio_update_msi(VFIOPCIDevice *vdev)
static void vfio_pci_load_rom(VFIOPCIDevice *vdev)
  {
-    g_autofree struct vfio_region_info *reg_info = NULL;
+    struct vfio_region_info *reg_info = NULL;
      uint64_t size;
      off_t off = 0;
      ssize_t bytes;
@@ -2665,7 +2665,7 @@ static VFIODeviceOps vfio_pci_ops = {
  bool vfio_populate_vga(VFIOPCIDevice *vdev, Error **errp)
  {
      VFIODevice *vbasedev = &vdev->vbasedev;
-    g_autofree struct vfio_region_info *reg_info = NULL;
+    struct vfio_region_info *reg_info = NULL;
      int ret;
ret = vfio_get_region_info(vbasedev, VFIO_PCI_VGA_REGION_INDEX, &reg_info);
@@ -2730,7 +2730,7 @@ bool vfio_populate_vga(VFIOPCIDevice *vdev, Error **errp)
  static bool vfio_populate_device(VFIOPCIDevice *vdev, Error **errp)
  {
      VFIODevice *vbasedev = &vdev->vbasedev;
-    g_autofree struct vfio_region_info *reg_info = NULL;
+    struct vfio_region_info *reg_info = NULL;
      struct vfio_irq_info irq_info = { .argsz = sizeof(irq_info) };
      int i, ret = -1;
@@ -3177,7 +3177,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp) if (!vdev->igd_opregion &&
          vdev->features & VFIO_FEATURE_ENABLE_IGD_OPREGION) {
-        g_autofree struct vfio_region_info *opregion = NULL;
+        struct vfio_region_info *opregion = NULL;
if (vdev->pdev.qdev.hotplugged) {
              error_setg(errp,
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index ae3ecbd9f6..304030e71d 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -151,6 +151,7 @@ typedef struct VFIODevice {
      IOMMUFDBackend *iommufd;
      VFIOIOASHwpt *hwpt;
      QLIST_ENTRY(VFIODevice) hwpt_next;
+    struct vfio_region_info **regions;
  } VFIODevice;
struct VFIODeviceOps {


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