From nobody Tue Apr 7 13:49:16 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 122F53D34AD; Wed, 25 Feb 2026 14:19:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772029199; cv=none; b=JDEjt2nE+G1bIv1g9nQG2IkZxfv5JozQsvfpcO6oRndIRDdwDf9uDyS8DmtnVLVDAupY1B5mqxsMRoq3M9N477Dhjqorr3RQnsC3qTKllwah8zCD7qNBVGihhH9wQ+MGyk3KjB2AhNuwBqYZGd4gYFoYL/kqtVAdI8DdPA8e2j8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772029199; c=relaxed/simple; bh=IWfIW+hzTkf5nStjv+pYV1pJ3Vmlm4ZHSTNuOGvG28E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=mRD9eFRJ9dp2lSb9LtRmepPvR7KrU7sXPdgKhQJEfrh54F5j52kyGOb2kFfOwQ7B0QLg9Xr8/fukI6K2dGBPpcU4QuoLaRSFIYCQIxlCS8YWIZcoVdMYVRPO4/eS5JCcXCuKeDtX8apwCt+ky6DDfwCmxPPaJf/fGP2z6PU4SFM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aMQF+tXJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aMQF+tXJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48714C116D0; Wed, 25 Feb 2026 14:19:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772029198; bh=IWfIW+hzTkf5nStjv+pYV1pJ3Vmlm4ZHSTNuOGvG28E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aMQF+tXJfP7CBNQnr+pR/bKhDKwwVWOMiGQqTKj63Ty1JgOGxyrGyH+lGjtG6aj28 N+tolxetZSs4XEjYAxrJXbH5QvzMGq8+AuAfkw5TbV0+jIWmGb1QvALgc05f+noXJ4 dGoZHWPjKTvYv8IwqNk1gNzF99XmsMdhVXg14jEzBCZwOTwQK9TR1nnB/IsHrB8TIp WQTn86d4i4bkuXh5TLKC6ltql3e5md4zkB87Gu+swkLUgSMoGIutrRvn3G5cslKAJj tx7OicPUFRzHsNNfQlQmHBxWnH+8ZnWlcFIIIyiiGaKnVn6k9LxYVNs0keMISewCEr fSjlrAvNMuiDw== From: Leon Romanovsky To: Saeed Mahameed , Leon Romanovsky , Tariq Toukan , Mark Bloch , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jason Gunthorpe Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Maher Sanalla Subject: [PATCH rdma-next 6/6] RDMA/mlx5: Add VAR object query method for cross-process sharing Date: Wed, 25 Feb 2026 16:19:36 +0200 Message-ID: <20260225-var-tlp-v1-6-fe14a7ac7731@nvidia.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260225-var-tlp-v1-0-fe14a7ac7731@nvidia.com> References: <20260225-var-tlp-v1-0-fe14a7ac7731@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" X-Mailer: b4 0.15-dev-47773 Content-Transfer-Encoding: quoted-printable From: Maher Sanalla Introduce MLX5_IB_METHOD_VAR_OBJ_QUERY to enable cross-process sharing of VAR objects. This method allows a process that has imported the uverbs fd via ibv_import_device() to query an existing VAR handle and obtain the mmap parameters needed to map the VAR region into its address space. This follows the same pattern as UVERBS_METHOD_QUERY_MR, allowing userspace to implement mlx5dv_import_var() analogous to ibv_import_mr(). Signed-off-by: Maher Sanalla Signed-off-by: Leon Romanovsky --- drivers/infiniband/hw/mlx5/main.c | 47 ++++++++++++++++++++++++++++= +++- include/uapi/rdma/mlx5_user_ioctl_cmds.h | 8 ++++++ 2 files changed, 54 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5= /main.c index 77cd11c6cca9..a75769f55d31 100644 --- a/drivers/infiniband/hw/mlx5/main.c +++ b/drivers/infiniband/hw/mlx5/main.c @@ -4263,6 +4263,34 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_VAR_OBJ_ALL= OC)( return err; } =20 +static int UVERBS_HANDLER(MLX5_IB_METHOD_VAR_OBJ_QUERY)( + struct uverbs_attr_bundle *attrs) +{ + struct mlx5_user_mmap_entry *entry =3D + uverbs_attr_get_obj(attrs, MLX5_IB_ATTR_VAR_OBJ_QUERY_HANDLE); + u64 mmap_offset; + u32 length; + int err; + + mmap_offset =3D mlx5_entry_to_mmap_offset(entry); + if (check_mul_overflow(entry->rdma_entry.npages, (u32)PAGE_SIZE, &length)) + return -EOVERFLOW; + + err =3D uverbs_copy_to(attrs, MLX5_IB_ATTR_VAR_OBJ_QUERY_MMAP_OFFSET, + &mmap_offset, sizeof(mmap_offset)); + if (err) + return err; + + err =3D uverbs_copy_to(attrs, MLX5_IB_ATTR_VAR_OBJ_QUERY_PAGE_ID, + &entry->page_idx, sizeof(entry->page_idx)); + if (err) + return err; + + err =3D uverbs_copy_to(attrs, MLX5_IB_ATTR_VAR_OBJ_QUERY_MMAP_LENGTH, + &length, sizeof(length)); + return err; +} + DECLARE_UVERBS_NAMED_METHOD( MLX5_IB_METHOD_VAR_OBJ_ALLOC, UVERBS_ATTR_IDR(MLX5_IB_ATTR_VAR_OBJ_ALLOC_HANDLE, @@ -4289,10 +4317,27 @@ DECLARE_UVERBS_NAMED_METHOD_DESTROY( UVERBS_ACCESS_DESTROY, UA_MANDATORY)); =20 +DECLARE_UVERBS_NAMED_METHOD( + MLX5_IB_METHOD_VAR_OBJ_QUERY, + UVERBS_ATTR_IDR(MLX5_IB_ATTR_VAR_OBJ_QUERY_HANDLE, + MLX5_IB_OBJECT_VAR, + UVERBS_ACCESS_READ, + UA_MANDATORY), + UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_VAR_OBJ_QUERY_PAGE_ID, + UVERBS_ATTR_TYPE(u32), + UA_MANDATORY), + UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_VAR_OBJ_QUERY_MMAP_LENGTH, + UVERBS_ATTR_TYPE(u32), + UA_MANDATORY), + UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_VAR_OBJ_QUERY_MMAP_OFFSET, + UVERBS_ATTR_TYPE(u64), + UA_MANDATORY)); + DECLARE_UVERBS_NAMED_OBJECT(MLX5_IB_OBJECT_VAR, UVERBS_TYPE_ALLOC_IDR(mmap_obj_cleanup), &UVERBS_METHOD(MLX5_IB_METHOD_VAR_OBJ_ALLOC), - &UVERBS_METHOD(MLX5_IB_METHOD_VAR_OBJ_DESTROY)); + &UVERBS_METHOD(MLX5_IB_METHOD_VAR_OBJ_DESTROY), + &UVERBS_METHOD(MLX5_IB_METHOD_VAR_OBJ_QUERY)); =20 static bool var_is_supported(struct ib_device *device) { diff --git a/include/uapi/rdma/mlx5_user_ioctl_cmds.h b/include/uapi/rdma/m= lx5_user_ioctl_cmds.h index 01a2a050e468..7db03b3fdae6 100644 --- a/include/uapi/rdma/mlx5_user_ioctl_cmds.h +++ b/include/uapi/rdma/mlx5_user_ioctl_cmds.h @@ -146,9 +146,17 @@ enum mlx5_ib_var_obj_destroy_attrs { MLX5_IB_ATTR_VAR_OBJ_DESTROY_HANDLE =3D (1U << UVERBS_ID_NS_SHIFT), }; =20 +enum mlx5_ib_var_obj_query_attrs { + MLX5_IB_ATTR_VAR_OBJ_QUERY_HANDLE =3D (1U << UVERBS_ID_NS_SHIFT), + MLX5_IB_ATTR_VAR_OBJ_QUERY_PAGE_ID, + MLX5_IB_ATTR_VAR_OBJ_QUERY_MMAP_OFFSET, + MLX5_IB_ATTR_VAR_OBJ_QUERY_MMAP_LENGTH, +}; + enum mlx5_ib_var_obj_methods { MLX5_IB_METHOD_VAR_OBJ_ALLOC =3D (1U << UVERBS_ID_NS_SHIFT), MLX5_IB_METHOD_VAR_OBJ_DESTROY, + MLX5_IB_METHOD_VAR_OBJ_QUERY, }; =20 enum mlx5_ib_uar_alloc_attrs { --=20 2.53.0