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Re: [PATCH v1 09/22] vfio/container: Introduce vfio_[attach/detach]_devi
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From: |
Cédric Le Goater |
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Subject: |
Re: [PATCH v1 09/22] vfio/container: Introduce vfio_[attach/detach]_device |
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Date: |
Thu, 21 Sep 2023 11:44:48 +0200 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 |
On 8/30/23 12:37, Zhenzhong Duan wrote:
From: Eric Auger <eric.auger@redhat.com>
We want the VFIO devices to be able to use two different
IOMMU callbacks, the legacy VFIO one and the new iommufd one.
Introduce vfio_[attach/detach]_device which aim at hiding the
underlying IOMMU backend (IOCTLs, datatypes, ...).
Once vfio_attach_device completes, the device is attached
to a security context and its fd can be used. Conversely
When vfio_detach_device completes, the device has been
detached to the security context.
In this patch, only the vfio-pci device gets converted to use
the new API. Subsequent patches will handle other devices.
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
hw/vfio/container.c | 66 +++++++++++++++++++++++++++++++++++
hw/vfio/pci.c | 50 ++++----------------------
hw/vfio/trace-events | 2 +-
include/hw/vfio/vfio-common.h | 3 ++
4 files changed, 76 insertions(+), 45 deletions(-)
diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index 175cdbbdff..74556da0c7 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -1083,3 +1083,69 @@ int vfio_eeh_as_op(AddressSpace *as, uint32_t op)
}
return vfio_eeh_container_op(container, op);
}
+
+static int vfio_device_groupid(VFIODevice *vbasedev, Error **errp)
+{
+ char *tmp, group_path[PATH_MAX], *group_name;
+ int ret, groupid;
+ ssize_t len;
+
+ tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
+ len = readlink(tmp, group_path, sizeof(group_path));
+ g_free(tmp);
+
+ if (len <= 0 || len >= sizeof(group_path)) {
+ ret = len < 0 ? -errno : -ENAMETOOLONG;
+ error_setg_errno(errp, -ret, "no iommu_group found");
+ return ret;
+ }
+
+ group_path[len] = 0;
+
+ group_name = basename(group_path);
+ if (sscanf(group_name, "%d", &groupid) != 1) {
+ error_setg_errno(errp, errno, "failed to read %s", group_path);
+ return -errno;
+ }
+ return groupid;
+}
VFIO has 4 other routines reading the iommu_group from sysfs :
vfio_ccw_get_group()
vfio_ap_get_group()
vfio_base_device_init()
sysfs_find_group_file()
which could use this helper. Thanks for introducing it !
+
+int vfio_attach_device(char *name, VFIODevice *vbasedev,
+ AddressSpace *as, Error **errp)
+{
+ int groupid = vfio_device_groupid(vbasedev, errp);
+ VFIODevice *vbasedev_iter;
+ VFIOGroup *group;
+ int ret;
+
+ if (groupid < 0) {
+ return groupid;
+ }
+
+ group = vfio_get_group(groupid, as, errp);
+ if (!group) {
+ return -ENOENT;
+ }
+
+ QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
+ if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
+ error_setg(errp, "device is already attached");
+ vfio_put_group(group);
+ return -EBUSY;
+ }
+ }
+ ret = vfio_get_device(group, name, vbasedev, errp);
+ if (ret) {
+ vfio_put_group(group);
+ }
+
+ return ret;
+}
+
+void vfio_detach_device(VFIODevice *vbasedev)
+{
+ VFIOGroup *group = vbasedev->group;
+
+ vfio_put_base_device(vbasedev);
+ vfio_put_group(group);
+}
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index a205c6b113..34f65ecd17 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2828,10 +2828,10 @@ static void vfio_populate_device(VFIOPCIDevice *vdev,
Error **errp)
static void vfio_put_device(VFIOPCIDevice *vdev)
{
+ vfio_detach_device(&vdev->vbasedev);
+
g_free(vdev->vbasedev.name);
g_free(vdev->msix);
-
- vfio_put_base_device(&vdev->vbasedev);
}
static void vfio_err_notifier_handler(void *opaque)
@@ -2978,13 +2978,9 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
{
VFIOPCIDevice *vdev = VFIO_PCI(pdev);
VFIODevice *vbasedev = &vdev->vbasedev;
- VFIODevice *vbasedev_iter;
- VFIOGroup *group;
- char *tmp, *subsys, group_path[PATH_MAX], *group_name;
+ char *tmp, *subsys;
Error *err = NULL;
- ssize_t len;
struct stat st;
- int groupid;
int i, ret;
bool is_mdev;
char uuid[UUID_FMT_LEN];
@@ -3015,38 +3011,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
vbasedev->type = VFIO_DEVICE_TYPE_PCI;
vbasedev->dev = DEVICE(vdev);
- tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
- len = readlink(tmp, group_path, sizeof(group_path));
- g_free(tmp);
-
- if (len <= 0 || len >= sizeof(group_path)) {
- error_setg_errno(errp, len < 0 ? errno : ENAMETOOLONG,
- "no iommu_group found");
- goto error;
- }
-
- group_path[len] = 0;
-
- group_name = basename(group_path);
- if (sscanf(group_name, "%d", &groupid) != 1) {
- error_setg_errno(errp, errno, "failed to read %s", group_path);
- goto error;
- }
-
- trace_vfio_realize(vbasedev->name, groupid);
-
- group = vfio_get_group(groupid, pci_device_iommu_address_space(pdev),
errp);
- if (!group) {
- goto error;
- }
-
- QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
- if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
- error_setg(errp, "device is already attached");
- vfio_put_group(group);
- goto error;
- }
- }
+ trace_vfio_realize(vbasedev->name);
I would move the trace event after vfio_attach_device() and print out the group.
Or simply add trace events in vfio_detach/attach_device().
This is a general comment on the VFIO PCI routines which do not use a 'vfio_pci'
prefix and I find it confusing, sometimes. Like this call stack :
vfio_put_device()
vfio_detach_device()
vfio_put_base_device()
I think we should rename vfio_put_device() in vfio_pci_put_device(). This is
not for this series.
Thanks,
C.
/*
* Mediated devices *might* operate compatibly with discarding of RAM, but
@@ -3065,7 +3030,6 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
if (vbasedev->ram_block_discard_allowed && !is_mdev) {
error_setg(errp, "x-balloon-allowed only potentially compatible "
"with mdev devices");
- vfio_put_group(group);
goto error;
}
@@ -3076,10 +3040,10 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
name = g_strdup(vbasedev->name);
}
- ret = vfio_get_device(group, name, vbasedev, errp);
+ ret = vfio_attach_device(name, vbasedev,
+ pci_device_iommu_address_space(pdev), errp);
g_free(name);
if (ret) {
- vfio_put_group(group);
goto error;
}
@@ -3318,7 +3282,6 @@ error:
static void vfio_instance_finalize(Object *obj)
{
VFIOPCIDevice *vdev = VFIO_PCI(obj);
- VFIOGroup *group = vdev->vbasedev.group;
vfio_display_finalize(vdev);
vfio_bars_finalize(vdev);
@@ -3332,7 +3295,6 @@ static void vfio_instance_finalize(Object *obj)
* g_free(vdev->igd_opregion);
*/
vfio_put_device(vdev);
- vfio_put_group(group);
}
static void vfio_exitfn(PCIDevice *pdev)
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index ee7509e68e..8016d9f0d2 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -37,7 +37,7 @@ vfio_pci_hot_reset_dep_devices(int domain, int bus, int slot,
int function, int
vfio_pci_hot_reset_result(const char *name, const char *result) "%s hot reset:
%s"
vfio_populate_device_config(const char *name, unsigned long size, unsigned long offset,
unsigned long flags) "Device %s config:\n size: 0x%lx, offset: 0x%lx, flags:
0x%lx"
vfio_populate_device_get_irq_info_failure(const char *errstr)
"VFIO_DEVICE_GET_IRQ_INFO failure: %s"
-vfio_realize(const char *name, int group_id) " (%s) group %d"
+vfio_realize(const char *name) " (%s)"
vfio_mdev(const char *name, bool is_mdev) " (%s) is_mdev %d"
vfio_add_ext_cap_dropped(const char *name, uint16_t cap, uint16_t offset) "%s
0x%x@0x%x"
vfio_pci_reset(const char *name) " (%s)"
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index bb7f9fe9c4..a29dfe7723 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -253,6 +253,9 @@ void vfio_put_group(VFIOGroup *group);
struct vfio_device_info *vfio_get_device_info(int fd);
int vfio_get_device(VFIOGroup *group, const char *name,
VFIODevice *vbasedev, Error **errp);
+int vfio_attach_device(char *name, VFIODevice *vbasedev,
+ AddressSpace *as, Error **errp);
+void vfio_detach_device(VFIODevice *vbasedev);
extern int vfio_kvm_device_fd;