Plumb through vfio_device_get_feature to the vfio-user server. Note that
we translate EINVAL into ENOTTY, as the existing generic vfio code is
expecting the latter to mean "unsupported".
As part of adding a trace point, clean up the trace file.
Signed-off-by: John Levon <john.levon@nutanix.com>
---
hw/vfio-user/protocol.h | 12 +++++++++++
hw/vfio-user/device.c | 42 +++++++++++++++++++++++++++++++++++++++
hw/vfio-user/trace-events | 23 +++++++++++----------
3 files changed, 67 insertions(+), 10 deletions(-)
diff --git a/hw/vfio-user/protocol.h b/hw/vfio-user/protocol.h
index 3249a4a6b6..2a0c31e7c5 100644
--- a/hw/vfio-user/protocol.h
+++ b/hw/vfio-user/protocol.h
@@ -40,6 +40,7 @@ enum vfio_user_command {
VFIO_USER_DEVICE_RESET = 13,
VFIO_USER_DIRTY_PAGES = 14,
VFIO_USER_REGION_WRITE_MULTI = 15,
+ VFIO_USER_DEVICE_FEATURE = 16,
VFIO_USER_MAX,
};
@@ -239,4 +240,15 @@ typedef struct {
VFIOUserWROne wrs[VFIO_USER_MULTI_MAX];
} VFIOUserWRMulti;
+/*
+ * VFIO_USER_DEVICE_FEATURE
+ * imported from struct vfio_device_feature
+ */
+typedef struct {
+ VFIOUserHdr hdr;
+ uint32_t argsz;
+ uint32_t flags;
+ char data[];
+} VFIOUserDeviceFeature;
+
#endif /* VFIO_USER_PROTOCOL_H */
diff --git a/hw/vfio-user/device.c b/hw/vfio-user/device.c
index 64ef35b320..b8d2b7c1a8 100644
--- a/hw/vfio-user/device.c
+++ b/hw/vfio-user/device.c
@@ -74,6 +74,47 @@ void vfio_user_device_reset(VFIOUserProxy *proxy)
}
}
+static int
+vfio_user_device_io_device_feature(VFIODevice *vbasedev,
+ struct vfio_device_feature *feature)
+{
+ g_autofree VFIOUserDeviceFeature *msgp = NULL;
+ int size = sizeof(VFIOUserHdr) + feature->argsz;
+ VFIOUserProxy *proxy = vbasedev->proxy;
+ Error *local_err = NULL;
+
+ msgp = g_malloc0(size);
+
+ vfio_user_request_msg(&msgp->hdr, VFIO_USER_DEVICE_FEATURE, size, 0);
+
+ memcpy(&msgp->argsz, &feature->argsz, feature->argsz);
+
+ if (!vfio_user_send_wait(proxy, &msgp->hdr, NULL, size, &local_err)) {
+ error_prepend(&local_err, "%s: ", __func__);
+ error_report_err(local_err);
+ return -EFAULT;
+ }
+
+ if (msgp->hdr.flags & VFIO_USER_ERROR) {
+ /*
+ * Client expects ENOTTY for "not supported", but the protocol may
+ * return EINVAL (which should only occur in the case the feature isn't
+ * actually supported on the server).
+ */
+ if (msgp->hdr.error_reply == EINVAL) {
+ return -ENOTTY;
+ }
+
+ return -msgp->hdr.error_reply;
+ }
+
+ memcpy(feature, &msgp->argsz, feature->argsz);
+
+ trace_vfio_user_device_io_device_feature(msgp->argsz, msgp->flags);
+
+ return 0;
+}
+
static int vfio_user_get_region_info(VFIOUserProxy *proxy,
struct vfio_region_info *info,
VFIOUserFDs *fds)
@@ -432,6 +473,7 @@ static int vfio_user_device_io_region_write(VFIODevice *vbasedev, uint8_t index,
* Socket-based io_ops
*/
VFIODeviceIOOps vfio_user_device_io_ops_sock = {
+ .device_feature = vfio_user_device_io_device_feature,
.get_region_info = vfio_user_device_io_get_region_info,
.get_irq_info = vfio_user_device_io_get_irq_info,
.set_irqs = vfio_user_device_io_set_irqs,
diff --git a/hw/vfio-user/trace-events b/hw/vfio-user/trace-events
index abb67f4c11..84714781cf 100644
--- a/hw/vfio-user/trace-events
+++ b/hw/vfio-user/trace-events
@@ -2,19 +2,22 @@
#
# SPDX-License-Identifier: GPL-2.0-or-later
-# common.c
+# container.c
+vfio_user_dma_map(uint64_t iova, uint64_t size, uint64_t off, uint32_t flags, bool async_ops) " iova 0x%"PRIx64" size 0x%"PRIx64" off 0x%"PRIx64" flags 0x%x async_ops %d"
+vfio_user_dma_unmap(uint64_t iova, uint64_t size, uint32_t flags, bool async_ops) " iova 0x%"PRIx64" size 0x%"PRIx64" flags 0x%x async_ops %d"
+
+# device.c
+vfio_user_device_io_device_feature(uint32_t argsz, uint32_t flags);
+vfio_user_get_info(uint32_t nregions, uint32_t nirqs) " #regions %d #irqs %d"
+vfio_user_get_irq_info(uint32_t index, uint32_t flags, uint32_t count) " index %d flags 0x%x count %d"
+vfio_user_set_irqs(uint32_t index, uint32_t start, uint32_t count, uint32_t flags) " index %d start %d count %d flags 0x%x"
+vfio_user_get_region_info(uint32_t index, uint32_t flags, uint64_t size) " index %d flags 0x%x size 0x%"PRIx64
+vfio_user_region_rw(uint32_t region, uint64_t off, uint32_t count) " region %d offset 0x%"PRIx64" count %d"
+
+# proxy.c
vfio_user_recv_hdr(const char *name, uint16_t id, uint16_t cmd, uint32_t size, uint32_t flags) " (%s) id 0x%x cmd 0x%x size 0x%x flags 0x%x"
vfio_user_recv_read(uint16_t id, int read) " id 0x%x read 0x%x"
vfio_user_recv_request(uint16_t cmd) " command 0x%x"
vfio_user_send_write(uint16_t id, int wrote) " id 0x%x wrote 0x%x"
vfio_user_version(uint16_t major, uint16_t minor, const char *caps) " major %d minor %d caps: %s"
-vfio_user_get_info(uint32_t nregions, uint32_t nirqs) " #regions %d #irqs %d"
-vfio_user_get_region_info(uint32_t index, uint32_t flags, uint64_t size) " index %d flags 0x%x size 0x%"PRIx64
-vfio_user_region_rw(uint32_t region, uint64_t off, uint32_t count) " region %d offset 0x%"PRIx64" count %d"
-vfio_user_get_irq_info(uint32_t index, uint32_t flags, uint32_t count) " index %d flags 0x%x count %d"
-vfio_user_set_irqs(uint32_t index, uint32_t start, uint32_t count, uint32_t flags) " index %d start %d count %d flags 0x%x"
vfio_user_wrmulti(const char *s, uint64_t wr_cnt) " %s count 0x%"PRIx64
-
-# container.c
-vfio_user_dma_map(uint64_t iova, uint64_t size, uint64_t off, uint32_t flags, bool async_ops) " iova 0x%"PRIx64" size 0x%"PRIx64" off 0x%"PRIx64" flags 0x%x async_ops %d"
-vfio_user_dma_unmap(uint64_t iova, uint64_t size, uint32_t flags, bool async_ops) " iova 0x%"PRIx64" size 0x%"PRIx64" flags 0x%x async_ops %d"
--
2.43.0On 4/9/26 12:47, John Levon wrote:
> Plumb through vfio_device_get_feature to the vfio-user server. Note that
> we translate EINVAL into ENOTTY, as the existing generic vfio code is
> expecting the latter to mean "unsupported".
>
> As part of adding a trace point, clean up the trace file.
>
> Signed-off-by: John Levon <john.levon@nutanix.com>
> ---
> hw/vfio-user/protocol.h | 12 +++++++++++
> hw/vfio-user/device.c | 42 +++++++++++++++++++++++++++++++++++++++
> hw/vfio-user/trace-events | 23 +++++++++++----------
> 3 files changed, 67 insertions(+), 10 deletions(-)
>
> diff --git a/hw/vfio-user/protocol.h b/hw/vfio-user/protocol.h
> index 3249a4a6b6..2a0c31e7c5 100644
> --- a/hw/vfio-user/protocol.h
> +++ b/hw/vfio-user/protocol.h
> @@ -40,6 +40,7 @@ enum vfio_user_command {
> VFIO_USER_DEVICE_RESET = 13,
> VFIO_USER_DIRTY_PAGES = 14,
> VFIO_USER_REGION_WRITE_MULTI = 15,
> + VFIO_USER_DEVICE_FEATURE = 16,
> VFIO_USER_MAX,
> };
>
> @@ -239,4 +240,15 @@ typedef struct {
> VFIOUserWROne wrs[VFIO_USER_MULTI_MAX];
> } VFIOUserWRMulti;
>
> +/*
> + * VFIO_USER_DEVICE_FEATURE
> + * imported from struct vfio_device_feature
> + */
> +typedef struct {
> + VFIOUserHdr hdr;
> + uint32_t argsz;
> + uint32_t flags;
> + char data[];
> +} VFIOUserDeviceFeature;
> +
> #endif /* VFIO_USER_PROTOCOL_H */
> diff --git a/hw/vfio-user/device.c b/hw/vfio-user/device.c
> index 64ef35b320..b8d2b7c1a8 100644
> --- a/hw/vfio-user/device.c
> +++ b/hw/vfio-user/device.c
> @@ -74,6 +74,47 @@ void vfio_user_device_reset(VFIOUserProxy *proxy)
> }
> }
>
> +static int
> +vfio_user_device_io_device_feature(VFIODevice *vbasedev,
> + struct vfio_device_feature *feature)
> +{
> + g_autofree VFIOUserDeviceFeature *msgp = NULL;
> + int size = sizeof(VFIOUserHdr) + feature->argsz;
> + VFIOUserProxy *proxy = vbasedev->proxy;
> + Error *local_err = NULL;
> +
> + msgp = g_malloc0(size);
> +
> + vfio_user_request_msg(&msgp->hdr, VFIO_USER_DEVICE_FEATURE, size, 0);
> +
> + memcpy(&msgp->argsz, &feature->argsz, feature->argsz);
> +
> + if (!vfio_user_send_wait(proxy, &msgp->hdr, NULL, size, &local_err)) {
> + error_prepend(&local_err, "%s: ", __func__);
> + error_report_err(local_err);
> + return -EFAULT;
> + }
> +
> + if (msgp->hdr.flags & VFIO_USER_ERROR) {
> + /*
> + * Client expects ENOTTY for "not supported", but the protocol may
> + * return EINVAL (which should only occur in the case the feature isn't
> + * actually supported on the server).
> + */
> + if (msgp->hdr.error_reply == EINVAL) {
> + return -ENOTTY;
> + }
May be this is not necessary anymore with :
https://lore.kernel.org/qemu-devel/20260409114312.1704062-1-clg@redhat.com/
> +
> + return -msgp->hdr.error_reply;
> + }
> +
> + memcpy(feature, &msgp->argsz, feature->argsz);
> +
> + trace_vfio_user_device_io_device_feature(msgp->argsz, msgp->flags);
> +
> + return 0;
> +}
> +
> static int vfio_user_get_region_info(VFIOUserProxy *proxy,
> struct vfio_region_info *info,
> VFIOUserFDs *fds)
> @@ -432,6 +473,7 @@ static int vfio_user_device_io_region_write(VFIODevice *vbasedev, uint8_t index,
> * Socket-based io_ops
> */
> VFIODeviceIOOps vfio_user_device_io_ops_sock = {
> + .device_feature = vfio_user_device_io_device_feature,
> .get_region_info = vfio_user_device_io_get_region_info,
> .get_irq_info = vfio_user_device_io_get_irq_info,
> .set_irqs = vfio_user_device_io_set_irqs,
> diff --git a/hw/vfio-user/trace-events b/hw/vfio-user/trace-events
> index abb67f4c11..84714781cf 100644
> --- a/hw/vfio-user/trace-events
> +++ b/hw/vfio-user/trace-events
> @@ -2,19 +2,22 @@
> #
> # SPDX-License-Identifier: GPL-2.0-or-later
>
> -# common.c
> +# container.c
> +vfio_user_dma_map(uint64_t iova, uint64_t size, uint64_t off, uint32_t flags, bool async_ops) " iova 0x%"PRIx64" size 0x%"PRIx64" off 0x%"PRIx64" flags 0x%x async_ops %d"
> +vfio_user_dma_unmap(uint64_t iova, uint64_t size, uint32_t flags, bool async_ops) " iova 0x%"PRIx64" size 0x%"PRIx64" flags 0x%x async_ops %d"
> +
> +# device.c
> +vfio_user_device_io_device_feature(uint32_t argsz, uint32_t flags);
missing format here ^
Thanks,
C.
> +vfio_user_get_info(uint32_t nregions, uint32_t nirqs) " #regions %d #irqs %d"
> +vfio_user_get_irq_info(uint32_t index, uint32_t flags, uint32_t count) " index %d flags 0x%x count %d"
> +vfio_user_set_irqs(uint32_t index, uint32_t start, uint32_t count, uint32_t flags) " index %d start %d count %d flags 0x%x"
> +vfio_user_get_region_info(uint32_t index, uint32_t flags, uint64_t size) " index %d flags 0x%x size 0x%"PRIx64
> +vfio_user_region_rw(uint32_t region, uint64_t off, uint32_t count) " region %d offset 0x%"PRIx64" count %d"
> +
> +# proxy.c
> vfio_user_recv_hdr(const char *name, uint16_t id, uint16_t cmd, uint32_t size, uint32_t flags) " (%s) id 0x%x cmd 0x%x size 0x%x flags 0x%x"
> vfio_user_recv_read(uint16_t id, int read) " id 0x%x read 0x%x"
> vfio_user_recv_request(uint16_t cmd) " command 0x%x"
> vfio_user_send_write(uint16_t id, int wrote) " id 0x%x wrote 0x%x"
> vfio_user_version(uint16_t major, uint16_t minor, const char *caps) " major %d minor %d caps: %s"
> -vfio_user_get_info(uint32_t nregions, uint32_t nirqs) " #regions %d #irqs %d"
> -vfio_user_get_region_info(uint32_t index, uint32_t flags, uint64_t size) " index %d flags 0x%x size 0x%"PRIx64
> -vfio_user_region_rw(uint32_t region, uint64_t off, uint32_t count) " region %d offset 0x%"PRIx64" count %d"
> -vfio_user_get_irq_info(uint32_t index, uint32_t flags, uint32_t count) " index %d flags 0x%x count %d"
> -vfio_user_set_irqs(uint32_t index, uint32_t start, uint32_t count, uint32_t flags) " index %d start %d count %d flags 0x%x"
> vfio_user_wrmulti(const char *s, uint64_t wr_cnt) " %s count 0x%"PRIx64
> -
> -# container.c
> -vfio_user_dma_map(uint64_t iova, uint64_t size, uint64_t off, uint32_t flags, bool async_ops) " iova 0x%"PRIx64" size 0x%"PRIx64" off 0x%"PRIx64" flags 0x%x async_ops %d"
> -vfio_user_dma_unmap(uint64_t iova, uint64_t size, uint32_t flags, bool async_ops) " iova 0x%"PRIx64" size 0x%"PRIx64" flags 0x%x async_ops %d"
On Thu, Apr 09, 2026 at 01:50:58PM +0200, Cédric Le Goater wrote:
> > + /*
> > + * Client expects ENOTTY for "not supported", but the protocol may
> > + * return EINVAL (which should only occur in the case the feature isn't
> > + * actually supported on the server).
> > + */
> > + if (msgp->hdr.error_reply == EINVAL) {
> > + return -ENOTTY;
> > + }
>
> May be this is not necessary anymore with :
>
> https://urldefense.proofpoint.com/v2/url?u=https-3A__lore.kernel.org_qemu-2Ddevel_20260409114312.1704062-2D1-2Dclg-40redhat.com_&d=DwICaQ&c=s883GpUCOChKOHiocYtGcg&r=v7SNLJqx7b9Vfc7ZO82Wg4nnZ8O5XkACFQ30bVKxotI&m=lpMrwUH_bH0I_KS0ucNhIf9acrnTdwuaRPGfJXRAj2yImpt5jpWGpP82gP4MJmRZ&s=9mI6zaw_Kt3ZLTto-WtxWPFKpQrqx-H7KpgUyvxnWEQ&e=
I think it's still necessary in general - ENOTTY is what kernel vfio returns so
we need to align for that for any other use cases.
> > +
> > +# device.c
> > +vfio_user_device_io_device_feature(uint32_t argsz, uint32_t flags);
>
> missing format here ^
Oops, surprised I didn't get errors with this
regards
john
>>> +# device.c >>> +vfio_user_device_io_device_feature(uint32_t argsz, uint32_t flags); >> >> missing format here ^ > > Oops, surprised I didn't get errors with this Can you please resend ? I am preparing the vfio queue for the next cycle. Thanks, C.
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