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Thu, 22 Feb 2024 15:16:44 -0800 From: Elliot Berman Date: Thu, 22 Feb 2024 15:16:55 -0800 Subject: [PATCH v17 32/35] virt: gunyah: Add irqfd interface MIME-Version: 1.0 Message-ID: <20240222-gunyah-v17-32-1e9da6763d38@quicinc.com> References: <20240222-gunyah-v17-0-1e9da6763d38@quicinc.com> In-Reply-To: <20240222-gunyah-v17-0-1e9da6763d38@quicinc.com> To: Alex Elder , Srinivas Kandagatla , Murali Nalajal , Trilok Soni , Srivatsa Vaddagiri , Carl van Schaik , Philip Derrin , Prakruthi Deepak Heragu , Jonathan Corbet , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Catalin Marinas , Will Deacon , Konrad Dybcio , Bjorn Andersson , Dmitry Baryshkov , "Fuad Tabba" , Sean Christopherson , "Andrew Morton" CC: , , , , , , Elliot Berman X-Mailer: b4 0.12.4 X-Originating-IP: [10.49.16.6] X-ClientProxiedBy: nalasex01c.na.qualcomm.com (10.47.97.35) 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: 4M5Sctox9093hyrqv1fhYVdp-QAefRVI X-Proofpoint-ORIG-GUID: 4M5Sctox9093hyrqv1fhYVdp-QAefRVI X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.1011,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2024-02-22_15,2024-02-22_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 suspectscore=0 clxscore=1015 lowpriorityscore=0 priorityscore=1501 adultscore=0 mlxlogscore=999 phishscore=0 spamscore=0 mlxscore=0 bulkscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2402120000 definitions=main-2402220179 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240222_231703_204277_9FDB238C X-CRM114-Status: GOOD ( 29.85 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Enable support for creating irqfds which can raise an interrupt on a Gunyah virtual machine. irqfds are exposed to userspace as a Gunyah VM function with the name "irqfd". If the VM devicetree is not configured to create a doorbell with the corresponding label, userspace will still be able to assert the eventfd but no interrupt will be raised on the guest. Acked-by: Alex Elder Co-developed-by: Prakruthi Deepak Heragu Signed-off-by: Prakruthi Deepak Heragu Signed-off-by: Elliot Berman --- drivers/virt/gunyah/Kconfig | 9 ++ drivers/virt/gunyah/Makefile | 1 + drivers/virt/gunyah/gunyah_irqfd.c | 187 +++++++++++++++++++++++++++++++++++++ include/uapi/linux/gunyah.h | 35 +++++++ 4 files changed, 232 insertions(+) diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig index fe2823dc48bac..1685b75fb77a0 100644 --- a/drivers/virt/gunyah/Kconfig +++ b/drivers/virt/gunyah/Kconfig @@ -27,3 +27,12 @@ config GUNYAH_QCOM_PLATFORM extra platform-specific support. Say Y/M here to use Gunyah on Qualcomm platforms. + +config GUNYAH_IRQFD + tristate "Gunyah irqfd interface" + depends on GUNYAH + help + Enable kernel support for creating irqfds which can raise an interrupt + on Gunyah virtual machine. + + 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 c4505fce177dd..b41b02792921c 100644 --- a/drivers/virt/gunyah/Makefile +++ b/drivers/virt/gunyah/Makefile @@ -5,3 +5,4 @@ gunyah_rsc_mgr-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mem.o guest_memfd.o obj-$(CONFIG_GUNYAH) += gunyah.o gunyah_rsc_mgr.o gunyah_vcpu.o obj-$(CONFIG_GUNYAH_PLATFORM_HOOKS) += gunyah_platform_hooks.o obj-$(CONFIG_GUNYAH_QCOM_PLATFORM) += gunyah_qcom.o +obj-$(CONFIG_GUNYAH_IRQFD) += gunyah_irqfd.o diff --git a/drivers/virt/gunyah/gunyah_irqfd.c b/drivers/virt/gunyah/gunyah_irqfd.c new file mode 100644 index 0000000000000..951da6e8d321e --- /dev/null +++ b/drivers/virt/gunyah/gunyah_irqfd.c @@ -0,0 +1,187 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +struct gunyah_irqfd { + struct gunyah_resource *ghrsc; + struct gunyah_vm_resource_ticket ticket; + struct gunyah_vm_function_instance *f; + + bool level; + + struct eventfd_ctx *ctx; + wait_queue_entry_t wait; + poll_table pt; +}; + +static int irqfd_wakeup(wait_queue_entry_t *wait, unsigned int mode, int sync, + void *key) +{ + struct gunyah_irqfd *irqfd = + container_of(wait, struct gunyah_irqfd, wait); + __poll_t flags = key_to_poll(key); + int ret = 0; + + if (flags & EPOLLIN) { + if (irqfd->ghrsc) { + ret = gunyah_hypercall_bell_send(irqfd->ghrsc->capid, 1, + NULL); + if (ret) + pr_err_ratelimited( + "Failed to inject interrupt %d: %d\n", + irqfd->ticket.label, ret); + } else + pr_err_ratelimited( + "Premature injection of interrupt\n"); + } + + return 0; +} + +static void irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, + poll_table *pt) +{ + struct gunyah_irqfd *irq_ctx = + container_of(pt, struct gunyah_irqfd, pt); + + add_wait_queue(wqh, &irq_ctx->wait); +} + +static bool gunyah_irqfd_populate(struct gunyah_vm_resource_ticket *ticket, + struct gunyah_resource *ghrsc) +{ + struct gunyah_irqfd *irqfd = + container_of(ticket, struct gunyah_irqfd, ticket); + int ret; + + if (irqfd->ghrsc) { + pr_warn("irqfd%d already got a Gunyah resource. Check if multiple resources with same label were configured.\n", + irqfd->ticket.label); + return false; + } + + irqfd->ghrsc = ghrsc; + if (irqfd->level) { + /* Configure the bell to trigger when bit 0 is asserted (see + * irq_wakeup) and for bell to automatically clear bit 0 once + * received by the VM (ack_mask). need to make sure bit 0 is cleared right away, + * otherwise the line will never be deasserted. Emulating edge + * trigger interrupt does not need to set either mask + * because irq is listed only once per gunyah_hypercall_bell_send + */ + ret = gunyah_hypercall_bell_set_mask(irqfd->ghrsc->capid, 1, 1); + if (ret) + pr_warn("irq %d couldn't be set as level triggered. Might cause IRQ storm if asserted\n", + irqfd->ticket.label); + } + + return true; +} + +static void gunyah_irqfd_unpopulate(struct gunyah_vm_resource_ticket *ticket, + struct gunyah_resource *ghrsc) +{ +} + +static long gunyah_irqfd_bind(struct gunyah_vm_function_instance *f) +{ + struct gunyah_fn_irqfd_arg *args = f->argp; + struct gunyah_irqfd *irqfd; + __poll_t events; + struct fd fd; + long r; + + if (f->arg_size != sizeof(*args)) + return -EINVAL; + + /* All other flag bits are reserved for future use */ + if (args->flags & ~GUNYAH_IRQFD_FLAGS_LEVEL) + return -EINVAL; + + irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL); + if (!irqfd) + return -ENOMEM; + + irqfd->f = f; + f->data = irqfd; + + fd = fdget(args->fd); + if (!fd.file) { + kfree(irqfd); + return -EBADF; + } + + irqfd->ctx = eventfd_ctx_fileget(fd.file); + if (IS_ERR(irqfd->ctx)) { + r = PTR_ERR(irqfd->ctx); + goto err_fdput; + } + + if (args->flags & GUNYAH_IRQFD_FLAGS_LEVEL) + irqfd->level = true; + + init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup); + init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc); + + irqfd->ticket.resource_type = GUNYAH_RESOURCE_TYPE_BELL_TX; + irqfd->ticket.label = args->label; + irqfd->ticket.owner = THIS_MODULE; + irqfd->ticket.populate = gunyah_irqfd_populate; + irqfd->ticket.unpopulate = gunyah_irqfd_unpopulate; + + r = gunyah_vm_add_resource_ticket(f->ghvm, &irqfd->ticket); + if (r) + goto err_ctx; + + events = vfs_poll(fd.file, &irqfd->pt); + if (events & EPOLLIN) + pr_warn("Premature injection of interrupt\n"); + fdput(fd); + + return 0; +err_ctx: + eventfd_ctx_put(irqfd->ctx); +err_fdput: + fdput(fd); + kfree(irqfd); + return r; +} + +static void gunyah_irqfd_unbind(struct gunyah_vm_function_instance *f) +{ + struct gunyah_irqfd *irqfd = f->data; + u64 cnt; + + eventfd_ctx_remove_wait_queue(irqfd->ctx, &irqfd->wait, &cnt); + gunyah_vm_remove_resource_ticket(irqfd->f->ghvm, &irqfd->ticket); + eventfd_ctx_put(irqfd->ctx); + kfree(irqfd); +} + +static bool gunyah_irqfd_compare(const struct gunyah_vm_function_instance *f, + const void *arg, size_t size) +{ + const struct gunyah_fn_irqfd_arg *instance = f->argp, *other = arg; + + if (sizeof(*other) != size) + return false; + + return instance->label == other->label; +} + +DECLARE_GUNYAH_VM_FUNCTION_INIT(irqfd, GUNYAH_FN_IRQFD, 2, gunyah_irqfd_bind, + gunyah_irqfd_unbind, gunyah_irqfd_compare); +MODULE_DESCRIPTION("Gunyah irqfd VM Function"); +MODULE_LICENSE("GPL"); diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h index 574116f544722..cb7b0bb9bef38 100644 --- a/include/uapi/linux/gunyah.h +++ b/include/uapi/linux/gunyah.h @@ -63,9 +63,12 @@ struct gunyah_vm_dtb_config { * @GUNYAH_FN_VCPU: create a vCPU instance to control a vCPU * &struct gunyah_fn_desc.arg is a pointer to &struct gunyah_fn_vcpu_arg * Return: file descriptor to manipulate the vcpu. + * @GUNYAH_FN_IRQFD: register eventfd to assert a Gunyah doorbell + * &struct gunyah_fn_desc.arg is a pointer to &struct gunyah_fn_irqfd_arg */ enum gunyah_fn_type { GUNYAH_FN_VCPU = 1, + GUNYAH_FN_IRQFD, }; #define GUNYAH_FN_MAX_ARG_SIZE 256 @@ -85,6 +88,38 @@ struct gunyah_fn_vcpu_arg { __u32 id; }; +/** + * enum gunyah_irqfd_flags - flags for use in gunyah_fn_irqfd_arg + * @GUNYAH_IRQFD_FLAGS_LEVEL: make the interrupt operate like a level triggered + * interrupt on guest side. Triggering IRQFD before + * guest handles the interrupt causes interrupt to + * stay asserted. + */ +enum gunyah_irqfd_flags { + GUNYAH_IRQFD_FLAGS_LEVEL = 1UL << 0, +}; + +/** + * struct gunyah_fn_irqfd_arg - Arguments to create an irqfd function. + * + * Create this function with &GUNYAH_VM_ADD_FUNCTION using type &GUNYAH_FN_IRQFD. + * + * Allows setting an eventfd to directly trigger a guest interrupt. + * irqfd.fd specifies the file descriptor to use as the eventfd. + * irqfd.label corresponds to the doorbell label used in the guest VM's devicetree. + * + * @fd: an eventfd which when written to will raise a doorbell + * @label: Label of the doorbell created on the guest VM + * @flags: see &enum gunyah_irqfd_flags + * @padding: padding bytes + */ +struct gunyah_fn_irqfd_arg { + __u32 fd; + __u32 label; + __u32 flags; + __u32 padding; +}; + /** * struct gunyah_fn_desc - Arguments to create a VM function * @type: Type of the function. See &enum gunyah_fn_type.