Messages in this thread | | | Date | Tue, 10 Jan 2023 10:16:50 -0800 | From | Elliot Berman <> | Subject | Re: [PATCH v8 09/28] mailbox: Add Gunyah message queue mailbox |
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On 1/9/2023 1:34 PM, Alex Elder wrote: > On 12/19/22 4:58 PM, Elliot Berman wrote: >> Gunyah message queues are a unidirectional inter-VM pipe for messages up > > s/Gunyah message queues are/A Gunyah message queue is/ > >> to 1024 bytes. This driver supports pairing a receiver message queue and >> a transmitter message queue to expose a single mailbox channel. >> >> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> >> --- >> Documentation/virt/gunyah/message-queue.rst | 8 + >> MAINTAINERS | 1 + >> drivers/mailbox/Kconfig | 10 + >> drivers/mailbox/Makefile | 2 + >> drivers/mailbox/gunyah-msgq.c | 229 ++++++++++++++++++++ >> include/linux/gunyah.h | 61 +++++- >> 6 files changed, 309 insertions(+), 2 deletions(-) >> create mode 100644 drivers/mailbox/gunyah-msgq.c >> >> diff --git a/Documentation/virt/gunyah/message-queue.rst >> b/Documentation/virt/gunyah/message-queue.rst >> index be4ab289236a..9245dbe6dd8a 100644 >> --- a/Documentation/virt/gunyah/message-queue.rst >> +++ b/Documentation/virt/gunyah/message-queue.rst >> @@ -54,3 +54,11 @@ vIRQ: two TX message queues will have two vIRQs >> (and two capability IDs). >> | | | | >> | | >> | | | | >> | | >> +---------------+ +-----------------+ >> +---------------+ >> + >> +Gunyah message queues are exposed as mailboxes. To create the >> mailbox, create >> +a mbox_client and call `gh_msgq_init`. On receipt of the RX_READY >> interrupt, >> +all messages in the RX message queue are read and pushed via the >> `rx_callback` >> +of the registered mbox_client. >> + >> +.. kernel-doc:: drivers/mailbox/gunyah-msgq.c >> + :identifiers: gh_msgq_init >> diff --git a/MAINTAINERS b/MAINTAINERS >> index 36698df6b0e5..667480bfd387 100644 >> --- a/MAINTAINERS >> +++ b/MAINTAINERS >> @@ -8942,6 +8942,7 @@ S: Supported >> F: Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml >> F: Documentation/virt/gunyah/ >> F: arch/arm64/gunyah/ >> +F: drivers/mailbox/gunyah-msgq.c >> F: drivers/virt/gunyah/ >> F: include/linux/gunyah.h >> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig >> index 05d6fae800e3..baf9451c5f04 100644 >> --- a/drivers/mailbox/Kconfig >> +++ b/drivers/mailbox/Kconfig >> @@ -41,6 +41,16 @@ config IMX_MBOX >> help >> Mailbox implementation for i.MX Messaging Unit (MU). >> +config GUNYAH_MESSAGE_QUEUES > > Is Gunyah useful without message queues? Are Gunyah message > queues useful without the rest of Gunyah? Are there other > possible message queue implementations? My point is that > maybe this isn't a necessary kernel config option. >
I can drop this.
>> + tristate "Gunyah Message Queue Mailbox" >> + depends on GUNYAH >> + help >> + Mailbox implementation for Gunyah Message Queues. Gunyah >> message queues >> + are an IPC mechanism to pass short messages between virtual >> machines >> + running under the Gunyah hypervisor. >> + >> + Say Y here if you run Linux as a Gunyah virtual machine. >> + >> config PLATFORM_MHU >> tristate "Platform MHU Mailbox" >> depends on OF >> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile >> index fc9376117111..5f929bb55e9a 100644 >> --- a/drivers/mailbox/Makefile >> +++ b/drivers/mailbox/Makefile >> @@ -55,6 +55,8 @@ obj-$(CONFIG_MTK_CMDQ_MBOX) += mtk-cmdq-mailbox.o >> obj-$(CONFIG_ZYNQMP_IPI_MBOX) += zynqmp-ipi-mailbox.o >> +obj-$(CONFIG_GUNYAH) += gunyah-msgq.o > > Assuming you keep the Kconfig option, should this be > referring to CONFIG_GUNYAH_MESSAGE_QUEUES? > >> + >> obj-$(CONFIG_SUN6I_MSGBOX) += sun6i-msgbox.o >> obj-$(CONFIG_SPRD_MBOX) += sprd-mailbox.o >> diff --git a/drivers/mailbox/gunyah-msgq.c >> b/drivers/mailbox/gunyah-msgq.c >> new file mode 100644 >> index 000000000000..d5a324e85428 >> --- /dev/null >> +++ b/drivers/mailbox/gunyah-msgq.c >> @@ -0,0 +1,229 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights >> reserved. >> + */ >> + >> +#include <linux/mailbox_controller.h> >> +#include <linux/module.h> >> +#include <linux/interrupt.h> >> +#include <linux/gunyah.h> >> +#include <linux/printk.h> >> +#include <linux/init.h> >> +#include <linux/slab.h> >> +#include <linux/wait.h> >> + >> +#define mbox_chan_to_msgq(chan) (container_of(chan->mbox, struct >> gh_msgq, mbox)) >> + >> +static inline bool gh_msgq_has_tx(struct gh_msgq *msgq) >> +{ >> + return msgq->tx_ghrsc->type == GUNYAH_RESOURCE_TYPE_MSGQ_TX; > > I think this was pointed out elsewhere; I think msgq->tx_ghrsc > can be null. Same for msgq->rx_ghrsc below. > >> +} >> + >> +static inline bool gh_msgq_has_rx(struct gh_msgq *msgq) >> +{ >> + return msgq->rx_ghrsc->type == GUNYAH_RESOURCE_TYPE_MSGQ_RX; > > Is there any chance that a message queue would be created whose > type was anything other than MSGQ_RX? It's possible that there > is some generic resource code that needs this type field, but > in this case I don't see why it's important. > > And... If that's the case, I think it's perhaps clearer to > just replace calls to gs_msgq_has_rx(msgq) with: > > if (msgq->rx_ghrsc) > /* there is an RX message queue */ >
Yep, that's what I've done for v9.
>> +} >> + >> +static irqreturn_t gh_msgq_rx_irq_handler(int irq, void *data) >> +{ >> + struct gh_msgq *msgq = data; >> + struct gh_msgq_rx_data rx_data; >> + unsigned long gh_err; >> + ssize_t ret; >> + bool ready = false; >> + >> + do { > > Maybe: bool ready = true; > > while (ready) { >> + gh_err = gh_hypercall_msgq_recv(msgq->rx_ghrsc->capid, >> + (uintptr_t)&rx_data.data, sizeof(rx_data.data), >> + &rx_data.length, &ready); >> + if (gh_err == GH_ERROR_OK) { >> + mbox_chan_received_data(gh_msgq_chan(msgq), &rx_data); > > Maybe continue; > } > > if (gh_err != GH_ERROR_MSGQUEUE_EMPTY) > pr_warn(...); > > break; > >> + } else if (GH_ERROR_MSGQUEUE_EMPTY) { >> + break; >> + } else { >> + pr_warn("Failed to receive data from msgq for %s: %ld\n", > > s/%ld/%zd/ > >> + msgq->mbox.dev ? dev_name(msgq->mbox.dev) : "", ret); >> + break; >> + } >> + } while (ready); >> + >> + return IRQ_HANDLED; >> +} >> + >> +static irqreturn_t gh_msgq_tx_irq_handler(int irq, void *data) >> +{ >> + struct gh_msgq *msgq = data; >> + >> + mbox_chan_txdone(gh_msgq_chan(msgq), 0); >> + >> + return IRQ_HANDLED; >> +} >> + >> +static void gh_msgq_txdone_tasklet(struct tasklet_struct *tasklet) >> +{ >> + struct gh_msgq *msgq = container_of(tasklet, struct gh_msgq, >> txdone_tasklet); >> + >> + mbox_chan_txdone(gh_msgq_chan(msgq), msgq->last_status); >> +} >> + >> +static int gh_msgq_send_data(struct mbox_chan *chan, void *data) >> +{ >> + struct gh_msgq *msgq = mbox_chan_to_msgq(chan); >> + struct gh_msgq_tx_data *msgq_data = data; >> + u64 tx_flags = 0; >> + unsigned long ret; >> + bool ready; >> + >> + if (msgq_data->push) >> + tx_flags |= GH_HYPERCALL_MSGQ_TX_FLAGS_PUSH; >> + > > I probably missed something, but where is gh_hypercall_msgq_send() > defined? I'm interested in what the ready flag is used for. > (Can the return value encode that?) >
It's in arch/arm64/gunyah/gunyah_hypercall.c. The return values of encode whether more data can be received (ready flag).
>> + ret = gh_hypercall_msgq_send(msgq->tx_ghrsc->capid, >> msgq_data->length, >> + (uintptr_t)msgq_data->data, tx_flags, &ready); >> + >> + /** >> + * unlikely because Linux tracks state of msgq and should not try to >> + * send message when msgq is full. >> + */ > > Is it just unlikely, or is it impossible? >
This would require multiple mailbox controllers interacting with the same message queue.
The only way I can think this is possible is if the Gunyah drivers are unloaded when the message queue is full; drivers are then re-loaded before the receiver processes the messages. The initial internal state of the message queue controller assumes that there is space in the message queue. We would get a Tx vIRQ once space becomes available and the message would then be attempted to sent again. Since there's a safe flow to recover from a inconsistent internal state and it's very unlikely to start in that state, I don't think we need to add calls to check if the message queue is full during initialization.
>> + if (unlikely(ret == GH_ERROR_MSGQUEUE_FULL)) >> + return -EAGAIN; >> + >> + /** >> + * Propagate all other errors to client. If we return error to >> mailbox >> + * framework, then no other messages can be sent and nobody will >> know >> + * to retry this message. >> + */ >> + msgq->last_status = gh_remap_error(ret); >> + >> + /** >> + * This message was successfully sent, but message queue isn't >> ready to >> + * receive more messages because it's now full.Mailbox framework >> + * requires that we only report that message was transmitted only >> when > > s/only // (for one of them) > >> + * we're ready to transmit another message. We'll get that in the >> form >> + * of tx IRQ once the other side starts to drain the msgq. >> + */ >> + if (ret == GH_ERROR_OK && !ready) >> + return 0; >> + >> + /** >> + * We can send more messages. Mailbox frameworkrequires that tx >> done >> + * happens asynchronously to sending the message. Gunyah message >> queues >> + * tell us right away on the hypercall return whether we can send >> more >> + * messages. To work around this, defer the txdone to a tasklet. >> + */ >> + tasklet_schedule(&msgq->txdone_tasklet); >> + >> + return 0; >> +} >> + >> +struct mbox_chan_ops gh_msgq_ops = { >> + .send_data = gh_msgq_send_data, >> +}; >> + >> +/** >> + * gh_msgq_init() - Initialize a Gunyah message queue with an >> mbox_client >> + * @parent: optional, device parent used for the mailbox controller >> + * @msgq: Pointer to the gh_msgq to initialize >> + * @cl: A mailbox client to bind to the mailbox channel that the >> message queue creates >> + * @tx_ghrsc: optional, the transmission side of the message queue >> + * @rx_ghrsc: optional, the receiving side of the message queue >> + * >> + * At least one of tx_ghrsc and rx_ghrsc should be not NULL. Most >> message queue use cases come with >> + * a pair of message queues to facilitiate bidirectional >> communication. When tx_ghrsc is set, > > s/facilitiate/facilitate/ > >> + * the client can send messages with >> mbox_send_message(gh_msgq_chan(msgq), msg). When rx_ghrsc >> + * is set, the mbox_client should register an .rx_callback() and the >> message queue driver will >> + * push all available messages upon receiving the RX ready interrupt. >> The messages should be >> + * consumed or copied by the client right away as the gh_msgq_rx_data >> will be replaced/destroyed >> + * after the callback. >> + * >> + * Returns - 0 on success, negative otherwise >> + */ >> +int gh_msgq_init(struct device *parent, struct gh_msgq *msgq, struct >> mbox_client *cl, >> + struct gunyah_resource *tx_ghrsc, struct gunyah_resource >> *rx_ghrsc) >> +{ >> + int ret; >> + >> + /* Must have at least a tx_ghrsc or rx_ghrsc and that they are >> the right device types */ >> + if ((!tx_ghrsc && !rx_ghrsc) || >> + (tx_ghrsc && tx_ghrsc->type != GUNYAH_RESOURCE_TYPE_MSGQ_TX) || >> + (rx_ghrsc && rx_ghrsc->type != GUNYAH_RESOURCE_TYPE_MSGQ_RX)) > > The internal parenthesis pairs above aren't really required. > >
I think it's cleaner/easier to read this way.
>> + return -EINVAL; >> + >> + msgq->tx_ghrsc = tx_ghrsc; >> + msgq->rx_ghrsc = rx_ghrsc; >> + >> + msgq->mbox.dev = parent; >> + msgq->mbox.ops = &gh_msgq_ops; >> + msgq->mbox.num_chans = 1; >> + msgq->mbox.chans = kcalloc(msgq->mbox.num_chans, >> sizeof(*msgq->mbox.chans), GFP_KERNEL); >> + if (!msgq->mbox.chans) >> + return -ENOMEM; >> + msgq->mbox.txdone_irq = true; >> + >> + if (gh_msgq_has_tx(msgq)) { > > Maybe if (tx_ghrsc) { > >> + ret = request_irq(msgq->tx_ghrsc->irq, >> gh_msgq_tx_irq_handler, 0, "gh_msgq_tx", >> + msgq); >> + if (ret) >> + gotoerr_chans; >> + } >> + >> + if (gh_msgq_has_rx(msgq)) { > > Maybe if (rx_ghrsc) { > >> + ret = request_threaded_irq(msgq->rx_ghrsc->irq, NULL, >> gh_msgq_rx_irq_handler, >> + IRQF_ONESHOT, "gh_msgq_rx", msgq); >> + if (ret) >> + gotoerr_tx_irq; >> + } >> + >> + tasklet_setup(&msgq->txdone_tasklet, gh_msgq_txdone_tasklet); >> + >> + ret = mbox_controller_register(&msgq->mbox); >> + if (ret) >> + goto err_rx_irq; >> + >> + ret = mbox_bind_client(gh_msgq_chan(msgq), cl); >> + if (ret) >> + goto err_mbox; >> + >> + return 0; >> +err_mbox: >> + mbox_controller_unregister(&msgq->mbox); >> +err_rx_irq: >> + if (gh_msgq_has_rx(msgq)) > > if (rx_ghrsc) > >> + free_irq(msgq->rx_ghrsc->irq, msgq); >> +err_tx_irq: >> + if (gh_msgq_has_tx(msgq)) > > if (tx_ghrsc) >
Applied for the suggestions above.
>> + free_irq(msgq->tx_ghrsc->irq, msgq); >> +err_chans: >> + kfree(msgq->mbox.chans); >> + return ret; >> +} >> +EXPORT_SYMBOL_GPL(gh_msgq_init); >> + >> +void gh_msgq_remove(struct gh_msgq *msgq) >> +{ >> + mbox_controller_unregister(&msgq->mbox); >> + >> + if (gh_msgq_has_rx(msgq)) >> + free_irq(msgq->rx_ghrsc->irq, msgq); >> + >> + if (gh_msgq_has_tx(msgq)) >> + free_irq(msgq->tx_ghrsc->irq, msgq); >> + >> + kfree(msgq->mbox.chans); >> +} >> +EXPORT_SYMBOL_GPL(gh_msgq_remove); >> + >> + >> +static int __init gh_msgq_init_module(void) >> +{ >> + if (gh_api_version() != GUNYAH_API_V1) { >> + pr_warn("Unrecognized gunyahversion: %u. Currently >> supported: %d\n", >> + gh_api_version(), GUNYAH_API_V1); >> + return -ENODEV; >> + } >> + >> + return 0; >> +} >> +module_init(gh_msgq_init_module); >> + >> +MODULE_LICENSE("GPL"); >> +MODULE_DESCRIPTION("Gunyah Message Queue Driver"); >> diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h >> index c863cac4a3cf..e317d7ac938f 100644 >> --- a/include/linux/gunyah.h >> +++ b/include/linux/gunyah.h >> @@ -7,10 +7,67 @@ >> #define _GUNYAH_H >> #include <linux/bitfield.h> >> -#include <linux/types.h> >> #include <linux/errno.h> >> +#include <linux/interrupt.h> >> +#include <linux/mailbox_controller.h> >> +#include <linux/mailbox_client.h> >> +#include <linux/types.h> >> + >> +/* Follows resource manager's resource types for VM_GET_HYP_RESOURCES */ >> +enum gunyah_resource_type { >> + GUNYAH_RESOURCE_TYPE_BELL_TX = 0, >> + GUNYAH_RESOURCE_TYPE_BELL_RX = 1, >> + GUNYAH_RESOURCE_TYPE_MSGQ_TX = 2, >> + GUNYAH_RESOURCE_TYPE_MSGQ_RX = 3, >> + GUNYAH_RESOURCE_TYPE_VCPU = 4, >> +}; >> + >> +struct gunyah_resource { >> + enum gunyah_resource_type type; >> + u64 capid; >> + int irq; >> +}; >> + >> +/** >> + * Gunyah Message Queues >> + */ >> + >> +#define GH_MSGQ_MAX_MSG_SIZE 240 >> + >> +struct gh_msgq_tx_data { >> + size_t length; >> + bool push; >> + char data[]; >> +}; >> + >> +struct gh_msgq_rx_data { >> + size_t length; >> + char data[GH_MSGQ_MAX_MSG_SIZE]; >> +}; >> + >> +struct gh_msgq { >> + struct gunyah_resource *tx_ghrsc; >> + struct gunyah_resource *rx_ghrsc; >> + >> + /* msgq private */ >> + int last_status; > > Maybe note that last_status is an errno (and not GH_ERROR_*) >
Done, renamed to "last_ret".
> -Alex > >> + struct mbox_controller mbox; >> + struct tasklet_struct txdone_tasklet; >> +}; >> + >> + >> +int gh_msgq_init(struct device *parent, struct gh_msgq *msgq, struct >> mbox_client *cl, >> + struct gunyah_resource *tx_ghrsc, struct gunyah_resource >> *rx_ghrsc); >> +void gh_msgq_remove(struct gh_msgq *msgq); >> + >> +static inline struct mbox_chan *gh_msgq_chan(struct gh_msgq *msgq) >> +{ >> + return &msgq->mbox.chans[0]; >> +} >> + >> +/******************************************************************************/ >> +/* Common arch-independent macros and definitions for Gunyah >> hypercalls */ >> -/* Common Gunyah macros */ >> #define GH_CAPID_INVAL U64_MAX >> #define GH_VMID_ROOT_VM 0xff >
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