From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C35FAC7EE25 for ; Fri, 9 Jun 2023 17:34:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230320AbjFIReL (ORCPT ); Fri, 9 Jun 2023 13:34:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43468 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230373AbjFIReK (ORCPT ); Fri, 9 Jun 2023 13:34:10 -0400 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 83968E4E; Fri, 9 Jun 2023 10:34:07 -0700 (PDT) Received: from pps.filterd (m0279872.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 359Dj1Td002667; Fri, 9 Jun 2023 17:33:27 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=qcppdkim1; bh=y6PSJ/a4efM6fP1I3t21ItHgFrgYNVQ8HnAxTEOR8C0=; b=XhIa5+axDvH54JGeH6Mhj9+02iHlW09N6s2TA77PX35JSJP64Jbs1paOBOqvCsrXNzdm 9d++yp7XcQEib52JZPMBK9HOY5VWUzL44VKXn2K1rDAsdSmH6u5IpW1AmufWrU1kot/k k/IH/DV1g/bOfSXpjGb2CGgAmxtLIsds/xqdhLQfjOjM1HGHBmC2bQ6n9abD0adgMniu 5iWSrRc1TtpOiJpcKXxTh5bCBovLcyfBdnY4XMZUcmrPnmwvsrRCRDmJaVkV0o9TvRBp dE+DBcWO4Qn9tjpjpmYFk3rSIRPnUxWu9arKYe+c4iUdoIQtCP4ApYmwJYap3+MnVc3q pQ== Received: from nasanppmta01.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3r3nwet4h9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 09 Jun 2023 17:33:27 +0000 Received: from nasanex01b.na.qualcomm.com (nasanex01b.na.qualcomm.com [10.46.141.250]) by NASANPPMTA01.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 359HXQLk021351 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 9 Jun 2023 17:33:26 GMT Received: from [10.134.65.165] (10.80.80.8) by nasanex01b.na.qualcomm.com (10.46.141.250) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.42; Fri, 9 Jun 2023 10:33:25 -0700 Message-ID: <2f60fc9f-a8b2-fe8c-183a-5ee9b276b02d@quicinc.com> Date: Fri, 9 Jun 2023 10:33:25 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: Re: [PATCH v13 23/24] virt: gunyah: Add ioeventfd Content-Language: en-US To: Alex Elder , Srinivas Kandagatla , Prakruthi Deepak Heragu , Jonathan Corbet CC: Murali Nalajala , Trilok Soni , Srivatsa Vaddagiri , Carl van Schaik , Dmitry Baryshkov , Bjorn Andersson , "Konrad Dybcio" , Arnd Bergmann , "Greg Kroah-Hartman" , Rob Herring , Krzysztof Kozlowski , Bagas Sanjaya , Will Deacon , Andy Gross , Catalin Marinas , Jassi Brar , , , , , References: <20230509204801.2824351-1-quic_eberman@quicinc.com> <20230509204801.2824351-24-quic_eberman@quicinc.com> <85e7c3ae-0991-0ca9-909c-f38773f63894@linaro.org> From: Elliot Berman In-Reply-To: <85e7c3ae-0991-0ca9-909c-f38773f63894@linaro.org> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nasanex01b.na.qualcomm.com (10.46.141.250) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: ollpdWv-vbhs78Ds3TYrpqiVb4IgVe7L X-Proofpoint-ORIG-GUID: ollpdWv-vbhs78Ds3TYrpqiVb4IgVe7L X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.573,FMLib:17.11.176.26 definitions=2023-06-09_12,2023-06-09_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 malwarescore=0 mlxlogscore=999 phishscore=0 priorityscore=1501 suspectscore=0 clxscore=1015 spamscore=0 adultscore=0 mlxscore=0 lowpriorityscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2305260000 definitions=main-2306090145 Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 6/5/2023 12:50 PM, Alex Elder wrote: > On 5/9/23 3:48 PM, Elliot Berman wrote: >> Allow userspace to attach an ioeventfd to an mmio address within the >> guest. >> >> Co-developed-by: Prakruthi Deepak Heragu >> Signed-off-by: Prakruthi Deepak Heragu >> Signed-off-by: Elliot Berman > > Looks good.  One question below. > > Reviewed-by: Alex Elder > Thanks! >> --- >>   Documentation/virt/gunyah/vm-manager.rst |   2 +- >>   drivers/virt/gunyah/Kconfig              |   9 ++ >>   drivers/virt/gunyah/Makefile             |   1 + >>   drivers/virt/gunyah/gunyah_ioeventfd.c   | 130 +++++++++++++++++++++++ >>   include/uapi/linux/gunyah.h              |  37 +++++++ >>   5 files changed, 178 insertions(+), 1 deletion(-) >>   create mode 100644 drivers/virt/gunyah/gunyah_ioeventfd.c >> >> diff --git a/Documentation/virt/gunyah/vm-manager.rst >> b/Documentation/virt/gunyah/vm-manager.rst >> index c4960948c779..87838c5b5945 100644 >> --- a/Documentation/virt/gunyah/vm-manager.rst >> +++ b/Documentation/virt/gunyah/vm-manager.rst >> @@ -115,7 +115,7 @@ the VM *before* the VM starts. >>   The argument types are documented below: >>   .. kernel-doc:: include/uapi/linux/gunyah.h >> -   :identifiers: gh_fn_vcpu_arg gh_fn_irqfd_arg gh_irqfd_flags >> +   :identifiers: gh_fn_vcpu_arg gh_fn_irqfd_arg gh_irqfd_flags >> gh_fn_ioeventfd_arg gh_ioeventfd_flags >>   Gunyah VCPU API Descriptions >>   ---------------------------- >> diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig >> index bc2c46d9df94..63bebc5b9f82 100644 >> --- a/drivers/virt/gunyah/Kconfig >> +++ b/drivers/virt/gunyah/Kconfig >> @@ -48,3 +48,12 @@ config GUNYAH_IRQFD >>         on Gunyah virtual machine. >>         Say Y/M here if unsure and you want to support Gunyah VMMs. >> + >> +config GUNYAH_IOEVENTFD >> +    tristate "Gunyah ioeventfd interface" >> +    depends on GUNYAH >> +    help >> +      Enable kernel support for creating ioeventfds which can alert >> userspace >> +      when a Gunyah virtual machine accesses a memory address. >> + >> +      Say Y/M here if unsure and you want to support Gunyah VMMs. >> diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile >> index ad212a1cf967..63ca11e74796 100644 >> --- a/drivers/virt/gunyah/Makefile >> +++ b/drivers/virt/gunyah/Makefile >> @@ -8,3 +8,4 @@ obj-$(CONFIG_GUNYAH) += gunyah.o >>   obj-$(CONFIG_GUNYAH_VCPU) += gunyah_vcpu.o >>   obj-$(CONFIG_GUNYAH_IRQFD) += gunyah_irqfd.o >> +obj-$(CONFIG_GUNYAH_IOEVENTFD) += gunyah_ioeventfd.o >> diff --git a/drivers/virt/gunyah/gunyah_ioeventfd.c >> b/drivers/virt/gunyah/gunyah_ioeventfd.c >> new file mode 100644 >> index 000000000000..5b1b9fd9ac3a >> --- /dev/null >> +++ b/drivers/virt/gunyah/gunyah_ioeventfd.c >> @@ -0,0 +1,130 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All >> rights reserved. >> + */ >> + >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> + >> +#include >> + >> +struct gh_ioeventfd { >> +    struct gh_vm_function_instance *f; >> +    struct gh_vm_io_handler io_handler; >> + >> +    struct eventfd_ctx *ctx; >> +}; >> + >> +static int gh_write_ioeventfd(struct gh_vm_io_handler *io_dev, u64 >> addr, u32 len, u64 data) >> +{ >> +    struct gh_ioeventfd *iofd = container_of(io_dev, struct >> gh_ioeventfd, io_handler); > > Does a write of 0 bytes still signal an event? > From gunyah_ioeventfd perspective, yes. I don't think a write of 0 bytes is possible, but maybe you are thinking of scenario I'm not? >> + >> +    eventfd_signal(iofd->ctx, 1); >> +    return 0; >> +} >> + >> +static struct gh_vm_io_handler_ops io_ops = { >> +    .write = gh_write_ioeventfd, >> +}; >> + >> +static long gh_ioeventfd_bind(struct gh_vm_function_instance *f) >> +{ >> +    const struct gh_fn_ioeventfd_arg *args = f->argp; >> +    struct gh_ioeventfd *iofd; >> +    struct eventfd_ctx *ctx; >> +    int ret; >> + >> +    if (f->arg_size != sizeof(*args)) >> +        return -EINVAL; >> + >> +    /* All other flag bits are reserved for future use */ >> +    if (args->flags & ~GH_IOEVENTFD_FLAGS_DATAMATCH) >> +        return -EINVAL; >> + >> +    /* must be natural-word sized, or 0 to ignore length */ >> +    switch (args->len) { >> +    case 0: >> +    case 1: >> +    case 2: >> +    case 4: >> +    case 8: >> +        break; >> +    default: >> +        return -EINVAL; >> +    } >> + >> +    /* check for range overflow */ >> +    if (overflows_type(args->addr + args->len, u64)) >> +        return -EINVAL; >> + >> +    /* ioeventfd with no length can't be combined with DATAMATCH */ >> +    if (!args->len && (args->flags & GH_IOEVENTFD_FLAGS_DATAMATCH)) >> +        return -EINVAL; >> + >> +    ctx = eventfd_ctx_fdget(args->fd); >> +    if (IS_ERR(ctx)) >> +        return PTR_ERR(ctx); >> + >> +    iofd = kzalloc(sizeof(*iofd), GFP_KERNEL); >> +    if (!iofd) { >> +        ret = -ENOMEM; >> +        goto err_eventfd; >> +    } >> + >> +    f->data = iofd; >> +    iofd->f = f; >> + >> +    iofd->ctx = ctx; >> + >> +    if (args->flags & GH_IOEVENTFD_FLAGS_DATAMATCH) { >> +        iofd->io_handler.datamatch = true; >> +        iofd->io_handler.len = args->len; >> +        iofd->io_handler.data = args->datamatch; >> +    } >> +    iofd->io_handler.addr = args->addr; >> +    iofd->io_handler.ops = &io_ops; >> + >> +    ret = gh_vm_add_io_handler(f->ghvm, &iofd->io_handler); >> +    if (ret) >> +        goto err_io_dev_add; >> + >> +    return 0; >> + >> +err_io_dev_add: >> +    kfree(iofd); >> +err_eventfd: >> +    eventfd_ctx_put(ctx); >> +    return ret; >> +} >> + >> +static void gh_ioevent_unbind(struct gh_vm_function_instance *f) >> +{ >> +    struct gh_ioeventfd *iofd = f->data; >> + >> +    eventfd_ctx_put(iofd->ctx); >> +    gh_vm_remove_io_handler(iofd->f->ghvm, &iofd->io_handler); >> +    kfree(iofd); >> +} >> + >> +static bool gh_ioevent_compare(const struct gh_vm_function_instance *f, >> +                const void *arg, size_t size) >> +{ >> +    const struct gh_fn_ioeventfd_arg *instance = f->argp, >> +                     *other = arg; >> + >> +    if (sizeof(*other) != size) >> +        return false; >> + >> +    return instance->addr == other->addr; >> +} >> + >> +DECLARE_GH_VM_FUNCTION_INIT(ioeventfd, GH_FN_IOEVENTFD, 3, >> +                gh_ioeventfd_bind, gh_ioevent_unbind, >> +                gh_ioevent_compare); >> +MODULE_DESCRIPTION("Gunyah ioeventfd VM Function"); >> +MODULE_LICENSE("GPL"); >> diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h >> index 0c480c622686..fa1cae7419d2 100644 >> --- a/include/uapi/linux/gunyah.h >> +++ b/include/uapi/linux/gunyah.h >> @@ -79,10 +79,13 @@ struct gh_vm_dtb_config { >>    *              Return: file descriptor to manipulate the vcpu. >>    * @GH_FN_IRQFD: register eventfd to assert a Gunyah doorbell >>    *               &struct gh_fn_desc.arg is a pointer to &struct >> gh_fn_irqfd_arg >> + * @GH_FN_IOEVENTFD: register ioeventfd to trigger when VM faults on >> parameter >> + *                   &struct gh_fn_desc.arg is a pointer to &struct >> gh_fn_ioeventfd_arg >>    */ >>   enum gh_fn_type { >>       GH_FN_VCPU = 1, >>       GH_FN_IRQFD, >> +    GH_FN_IOEVENTFD, >>   }; >>   #define GH_FN_MAX_ARG_SIZE        256 >> @@ -134,6 +137,40 @@ struct gh_fn_irqfd_arg { >>       __u32 padding; >>   }; >> +/** >> + * enum gh_ioeventfd_flags - flags for use in gh_fn_ioeventfd_arg >> + * @GH_IOEVENTFD_FLAGS_DATAMATCH: the event will be signaled only if the >> + *                                written value to the registered >> address is >> + *                                equal to &struct >> gh_fn_ioeventfd_arg.datamatch >> + */ >> +enum gh_ioeventfd_flags { >> +    GH_IOEVENTFD_FLAGS_DATAMATCH    = 1UL << 0, >> +}; >> + >> +/** >> + * struct gh_fn_ioeventfd_arg - Arguments to create an ioeventfd >> function >> + * @datamatch: data used when GH_IOEVENTFD_DATAMATCH is set >> + * @addr: Address in guest memory >> + * @len: Length of access >> + * @fd: When ioeventfd is matched, this eventfd is written >> + * @flags: See &enum gh_ioeventfd_flags >> + * @padding: padding bytes >> + * >> + * Create this function with &GH_VM_ADD_FUNCTION using type >> &GH_FN_IOEVENTFD. >> + * >> + * Attaches an ioeventfd to a legal mmio address within the guest. A >> guest write >> + * in the registered address will signal the provided event instead >> of triggering >> + * an exit on the GH_VCPU_RUN ioctl. >> + */ >> +struct gh_fn_ioeventfd_arg { >> +    __u64 datamatch; >> +    __u64 addr;        /* legal mmio address */ >> +    __u32 len;         /* 1, 2, 4, or 8 bytes; or 0 to ignore length */ >> +    __s32 fd; >> +    __u32 flags; >> +    __u32 padding; >> +}; >> + >>   /** >>    * struct gh_fn_desc - Arguments to create a VM function >>    * @type: Type of the function. See &enum gh_fn_type. >