On 4/9/25 15:48, John Levon wrote:
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.
We will also need it to generalize region accesses, as that means we
can't use ->config_offset for configuration space accesses, but must
look up the region offset (if relevant) each time.
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/container.c | 10 ++++++++++
hw/vfio/device.c | 31 +++++++++++++++++++++++++++----
hw/vfio/igd.c | 8 ++++----
hw/vfio/pci.c | 6 +++---
hw/vfio/region.c | 2 +-
include/hw/vfio/vfio-device.h | 1 +
7 files changed, 46 insertions(+), 17 deletions(-)
diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
index dac8769925..14dee7cd19 100644
--- a/hw/vfio/ccw.c
+++ b/hw/vfio/ccw.c
@@ -504,7 +504,6 @@ 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_device_get_region_info_type(vdev, VFIO_REGION_TYPE_CCW,
@@ -517,7 +516,6 @@ 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_device_get_region_info_type(vdev, VFIO_REGION_TYPE_CCW,
@@ -530,7 +528,6 @@ 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_device_get_region_info_type(vdev, VFIO_REGION_TYPE_CCW,
@@ -544,7 +541,6 @@ 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;
@@ -554,7 +550,6 @@ 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/container.c b/hw/vfio/container.c
index 37b1217fd8..61333d7fc4 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -857,6 +857,16 @@ static bool vfio_device_get(VFIOGroup *group, const char
*name,
static void vfio_device_put(VFIODevice *vbasedev)
{
+ if (vbasedev->reginfo != NULL) {
+ int i;
+
+ for (i = 0; i < vbasedev->num_regions; i++) {
+ g_free(vbasedev->reginfo[i]);
+ }
+ g_free(vbasedev->reginfo);
+ vbasedev->reginfo = NULL;
+ }
+
Can we have a vfio_device_unprepare() routine for symmetry with
routine vfio_device_get_all_region_info() ? Naming should be
improved too.
if (!vbasedev->group) {> return;
}
diff --git a/hw/vfio/device.c b/hw/vfio/device.c
index 2966171118..102fa5a9b4 100644
--- a/hw/vfio/device.c
+++ b/hw/vfio/device.c
@@ -205,6 +205,17 @@ int vfio_device_get_region_info(VFIODevice *vbasedev, int
index,
{
size_t argsz = sizeof(struct vfio_region_info);
+ /* create region info cache */
+ if (vbasedev->reginfo == NULL) {
+ vbasedev->reginfo = g_new0(struct vfio_region_info *,
+ vbasedev->num_regions);
+ }
I guess we could allocate ->reginfo[] array sooner in the VFIODevice
object life cycle. Since we lack a realize handler, may be in
vfio_device_prepare() ?
+ /* check cache */
+ if (vbasedev->reginfo[index] != NULL) {
+ *info = vbasedev->reginfo[index];
+ return 0;
+ }
+
*info = g_malloc0(argsz);
(*info)->index = index;
@@ -224,6 +235,9 @@ retry:
goto retry;
}
+ /* fill cache */
+ vbasedev->reginfo[index] = *info;
+
return 0;
}
@@ -242,7 +256,6 @@ int vfio_device_get_region_info_type(VFIODevice *vbasedev, uint32_t type,
hdr = vfio_get_region_info_cap(*info, VFIO_REGION_INFO_CAP_TYPE);
if (!hdr) {
- g_free(*info);
continue;
}
@@ -254,8 +267,6 @@ int vfio_device_get_region_info_type(VFIODevice *vbasedev, uint32_t type,
if (cap_type->type == type && cap_type->subtype == subtype) {
return 0;
}
-
- g_free(*info);
}
*info = NULL;
@@ -264,7 +275,7 @@ int vfio_device_get_region_info_type(VFIODevice *vbasedev,
uint32_t type,
bool vfio_device_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_device_get_region_info(vbasedev, region, &info)) {
@@ -427,6 +438,16 @@ void vfio_device_detach(VFIODevice *vbasedev)
VFIO_IOMMU_GET_CLASS(vbasedev->bcontainer)->detach_device(vbasedev);
}
+static void vfio_device_get_all_region_info(VFIODevice *vbasedev)
+{
+ struct vfio_region_info *info;
+ int i;
+
+ for (i = 0; i < vbasedev->num_regions; i++) {
+ vfio_device_get_region_info(vbasedev, i, &info);
+ }
+}
+
if the vfio_device_get_all_region_info() routine queries *all* region
infos to fill the ->reginfo[] cache array, why do we also need the
lazy cache filling method in vfio_device_get_region_info() ? This looks
redundant to me. I would rather have vfio_device_get_region_info()
operate on the cache only.
Thanks,
C.
void vfio_device_prepare(VFIODevice *vbasedev, VFIOContainerBase *bcontainer,
struct vfio_device_info *info)
{
@@ -439,4 +460,6 @@ void vfio_device_prepare(VFIODevice *vbasedev,
VFIOContainerBase *bcontainer,
QLIST_INSERT_HEAD(&bcontainer->device_list, vbasedev, container_next);
QLIST_INSERT_HEAD(&vfio_device_list, vbasedev, global_next);
+
+ vfio_device_get_all_region_info(vbasedev);
}
diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c
index e1cba16399..d70da1ce38 100644
--- a/hw/vfio/igd.c
+++ b/hw/vfio/igd.c
@@ -198,7 +198,7 @@ static bool vfio_pci_igd_opregion_init(VFIOPCIDevice *vdev,
static bool vfio_pci_igd_setup_opregion(VFIOPCIDevice *vdev, Error **errp)
{
- g_autofree struct vfio_region_info *opregion = NULL;
+ struct vfio_region_info *opregion = NULL;
int ret;
/* Hotplugging is not supported for opregion access */
@@ -361,8 +361,8 @@ static int vfio_pci_igd_lpc_init(VFIOPCIDevice *vdev,
static bool vfio_pci_igd_setup_lpc_bridge(VFIOPCIDevice *vdev, Error **errp)
{
- g_autofree struct vfio_region_info *host = NULL;
- g_autofree struct vfio_region_info *lpc = NULL;
+ struct vfio_region_info *host = NULL;
+ struct vfio_region_info *lpc = NULL;
PCIDevice *lpc_bridge;
int ret;
@@ -526,7 +526,7 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
* - OpRegion
* - Same LPC bridge and Host bridge VID/DID/SVID/SSID as host
*/
- g_autofree struct vfio_region_info *rom = NULL;
+ struct vfio_region_info *rom = NULL;
legacy_mode_enabled = true;
info_report("IGD legacy mode enabled, "
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index c3842d2f8d..b40d5abdfd 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -882,8 +882,8 @@ static void vfio_update_msi(VFIOPCIDevice *vdev)
static void vfio_pci_load_rom(VFIOPCIDevice *vdev)
{
- g_autofree struct vfio_region_info *reg_info = NULL;
VFIODevice *vbasedev = &vdev->vbasedev;
+ struct vfio_region_info *reg_info = NULL;
uint64_t size;
off_t off = 0;
ssize_t bytes;
@@ -2721,7 +2721,7 @@ 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_device_get_region_info(vbasedev, VFIO_PCI_VGA_REGION_INDEX, ®_info);
@@ -2786,7 +2786,7 @@ 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;
int i, ret = -1;
diff --git a/hw/vfio/region.c b/hw/vfio/region.c
index 04bf9eb098..ef2630cac3 100644
--- a/hw/vfio/region.c
+++ b/hw/vfio/region.c
@@ -182,7 +182,7 @@ 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_device_get_region_info(vbasedev, index, &info);
diff --git a/include/hw/vfio/vfio-device.h b/include/hw/vfio/vfio-device.h
index 9522a09c48..967b07cd89 100644
--- a/include/hw/vfio/vfio-device.h
+++ b/include/hw/vfio/vfio-device.h
@@ -81,6 +81,7 @@ typedef struct VFIODevice {
IOMMUFDBackend *iommufd;
VFIOIOASHwpt *hwpt;
QLIST_ENTRY(VFIODevice) hwpt_next;
+ struct vfio_region_info **reginfo;
} VFIODevice;
struct VFIODeviceOps {
