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[67.161.114.176]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-70242c270c7sm6298153b3a.220.2024.06.03.22.10.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Jun 2024 22:10:47 -0700 (PDT) From: mhkelley58@gmail.com X-Google-Original-From: mhklinux@outlook.com To: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, lpieralisi@kernel.org, kw@linux.com, robh@kernel.org, bhelgaas@google.com, James.Bottomley@HansenPartnership.com, martin.petersen@oracle.com, arnd@arndb.de, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-scsi@vger.kernel.org, linux-arch@vger.kernel.org Cc: maz@kernel.org, den@valinux.co.jp, jgowans@amazon.com, dawei.li@shingroup.cn Subject: [RFC 09/12] Drivers: hv: vmbus: Use Linux IRQs to handle VMBus channel interrupts Date: Mon, 3 Jun 2024 22:09:37 -0700 Message-Id: <20240604050940.859909-10-mhklinux@outlook.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240604050940.859909-1-mhklinux@outlook.com> References: <20240604050940.859909-1-mhklinux@outlook.com> Reply-To: mhklinux@outlook.com Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Michael Kelley Do the following: 1) Create an interrupt handler for VMBus channel interrupts by pulling out portions of vmbus_chan_sched() into vmbus_chan_handler(). The outer part of vmbus_chan_sched() that loops through the synic event page bitmap remains unchanged. But when a pending VMBus channel interrupt is found, call generic_handle_irq_desc() to invoke handle_simple_irq() and then vmbus_chan_handler() for the channel's IRQ. handle_simple_irq() does the IRQ stats for that channel's IRQ, so that per-channel interrupt counts appear in /proc/interrupts. The overall processing of VMBus channel interrupts is unchanged except for the intervening handle_simple_irq() that does the stats. No acks or EOIs are required for VMBus channel IRQs. 2) Update __vmbus_open() to call request_irq(), specifying the previously setup channel IRQ name and vmbus_chan_handler() as the interrupt handler. Set the IRQ affinity to the target_cpu assigned when the channel was created. 3) Update vmbus_isr() to return "false" if it only handles VMBus interrupts, which were passed to the channel IRQ handler. If vmbus_isr() handles one or more control message interrupts, then return "true". Update the related definitions to specify a boolean return value. 4) The callers of vmbus_isr() increment IRQ stats for the top-level IRQ only if "true" is returned. On x86, the caller is sysvec_hyperv_callback(), which manages the stats directly. On arm64, the caller is vmbus_percpu_isr(), which maps the boolean return value to IRQ_NONE ("false") or IRQ_HANDLED ("true"). Then handle_percpu_demux_irq() conditionally updates the stats based on the return value from vmbus_percpu_isr(). With these changes, interrupts from VMBus channels are now processed as Linux IRQs that are demultiplexed from the main VMBus interrupt. Signed-off-by: Michael Kelley --- arch/x86/kernel/cpu/mshyperv.c | 9 ++-- drivers/hv/channel.c | 25 +++++++++- drivers/hv/hv_common.c | 2 +- drivers/hv/vmbus_drv.c | 84 +++++++++++++++++++--------------- include/asm-generic/mshyperv.h | 3 +- 5 files changed, 79 insertions(+), 44 deletions(-) diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index e0fd57a8ba84..18bc282a99db 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -110,7 +110,7 @@ void hv_set_msr(unsigned int reg, u64 value) } EXPORT_SYMBOL_GPL(hv_set_msr); -static void (*vmbus_handler)(void); +static bool (*vmbus_handler)(void); static void (*hv_stimer0_handler)(void); static void (*hv_kexec_handler)(void); static void (*hv_crash_handler)(struct pt_regs *regs); @@ -119,9 +119,8 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_callback) { struct pt_regs *old_regs = set_irq_regs(regs); - inc_irq_stat(irq_hv_callback_count); - if (vmbus_handler) - vmbus_handler(); + if (vmbus_handler && vmbus_handler()) + inc_irq_stat(irq_hv_callback_count); if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED) apic_eoi(); @@ -129,7 +128,7 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_callback) set_irq_regs(old_regs); } -void hv_setup_vmbus_handler(void (*handler)(void)) +void hv_setup_vmbus_handler(bool (*handler)(void)) { vmbus_handler = handler; } diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index fb8cd8469328..1aa020b538f1 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -638,6 +638,7 @@ static int __vmbus_open(struct vmbus_channel *newchannel, struct vmbus_channel_open_channel *open_msg; struct vmbus_channel_msginfo *open_info = NULL; struct page *page = newchannel->ringbuffer_page; + u32 relid = newchannel->offermsg.child_relid; u32 send_pages, recv_pages; unsigned long flags; int err; @@ -685,13 +686,31 @@ static int __vmbus_open(struct vmbus_channel *newchannel, if (err) goto error_free_gpadl; + /* Request the IRQ and assign to target_cpu */ + err = request_irq(newchannel->irq, vmbus_chan_handler, 0, + newchannel->irq_name, newchannel); + if (err) { + pr_err("request_irq failed with %d for relid %d irq %d\n", + err, relid, newchannel->irq); + goto error_free_gpadl; + } + err = irq_set_affinity_and_hint(newchannel->irq, + cpumask_of(newchannel->target_cpu)); + if (err) { + pr_err("irq_set_affinity_and_hint failed with %d for relid %d irq %d\n", + err, relid, newchannel->irq); + free_irq(newchannel->irq, newchannel); + goto error_free_gpadl; + } + newchannel->irq_requested = true; + /* Create and init the channel open message */ open_info = kzalloc(sizeof(*open_info) + sizeof(struct vmbus_channel_open_channel), GFP_KERNEL); if (!open_info) { err = -ENOMEM; - goto error_free_gpadl; + goto error_free_irq; } init_completion(&open_info->waitevent); @@ -759,6 +778,10 @@ static int __vmbus_open(struct vmbus_channel *newchannel, spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); error_free_info: kfree(open_info); +error_free_irq: + irq_update_affinity_hint(newchannel->irq, NULL); + free_irq(newchannel->irq, newchannel); + newchannel->irq_requested = false; error_free_gpadl: vmbus_teardown_gpadl(newchannel, &newchannel->ringbuffer_gpadlhandle); error_clean_ring: diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index 9c452bfbd571..38a23add721c 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -610,7 +610,7 @@ bool __weak hv_isolation_type_tdx(void) } EXPORT_SYMBOL_GPL(hv_isolation_type_tdx); -void __weak hv_setup_vmbus_handler(void (*handler)(void)) +void __weak hv_setup_vmbus_handler(bool (*handler)(void)) { } EXPORT_SYMBOL_GPL(hv_setup_vmbus_handler); diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 8fd03d41e71a..b73be7c02d37 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -1193,6 +1193,45 @@ static void vmbus_force_channel_rescinded(struct vmbus_channel *channel) } #endif /* CONFIG_PM_SLEEP */ +irqreturn_t vmbus_chan_handler(int irq, void *dev_id) +{ + void (*callback_fn)(void *context); + struct vmbus_channel *channel = dev_id; + + /* + * Make sure that the ring buffer data structure doesn't get + * freed while we dereference the ring buffer pointer. Test + * for the channel's onchannel_callback being NULL within a + * sched_lock critical section. See also the inline comments + * in vmbus_reset_channel_cb(). + */ + spin_lock(&channel->sched_lock); + + callback_fn = channel->onchannel_callback; + if (unlikely(callback_fn == NULL)) + goto spin_unlock; + + trace_vmbus_chan_sched(channel); + + ++channel->interrupts; + + switch (channel->callback_mode) { + case HV_CALL_ISR: + (*callback_fn)(channel->channel_callback_context); + break; + + case HV_CALL_BATCHED: + hv_begin_read(&channel->inbound); + fallthrough; + case HV_CALL_DIRECT: + tasklet_schedule(&channel->callback_event); + } + +spin_unlock: + spin_unlock(&channel->sched_lock); + return IRQ_HANDLED; +} + /* * Schedule all channels with events pending */ @@ -1217,7 +1256,6 @@ static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu) return; for_each_set_bit(relid, recv_int_page, maxbits) { - void (*callback_fn)(void *context); struct vmbus_channel *channel; struct irq_desc *desc; @@ -1244,43 +1282,14 @@ static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu) if (channel->rescind) goto sched_unlock_rcu; - /* - * Make sure that the ring buffer data structure doesn't get - * freed while we dereference the ring buffer pointer. Test - * for the channel's onchannel_callback being NULL within a - * sched_lock critical section. See also the inline comments - * in vmbus_reset_channel_cb(). - */ - spin_lock(&channel->sched_lock); - - callback_fn = channel->onchannel_callback; - if (unlikely(callback_fn == NULL)) - goto sched_unlock; - - trace_vmbus_chan_sched(channel); - - ++channel->interrupts; - - switch (channel->callback_mode) { - case HV_CALL_ISR: - (*callback_fn)(channel->channel_callback_context); - break; - - case HV_CALL_BATCHED: - hv_begin_read(&channel->inbound); - fallthrough; - case HV_CALL_DIRECT: - tasklet_schedule(&channel->callback_event); - } + generic_handle_irq_desc(desc); -sched_unlock: - spin_unlock(&channel->sched_lock); sched_unlock_rcu: rcu_read_unlock(); } } -static void vmbus_isr(void) +static bool vmbus_isr(void) { struct hv_per_cpu_context *hv_cpu = this_cpu_ptr(hv_context.cpu_context); @@ -1299,15 +1308,18 @@ static void vmbus_isr(void) vmbus_signal_eom(msg, HVMSG_TIMER_EXPIRED); } else tasklet_schedule(&hv_cpu->msg_dpc); - } - add_interrupt_randomness(vmbus_interrupt); + add_interrupt_randomness(vmbus_interrupt); + return true; + } + return false; } static irqreturn_t vmbus_percpu_isr(int irq, void *dev_id) { - vmbus_isr(); - return IRQ_HANDLED; + if (vmbus_isr()) + return IRQ_HANDLED; + return IRQ_NONE; } int vmbus_irq_set_affinity(struct irq_data *data, diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h index 0488ff8b511f..0a5559b9d5f7 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -178,7 +178,7 @@ static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type) int hv_get_hypervisor_version(union hv_hypervisor_version_info *info); -void hv_setup_vmbus_handler(void (*handler)(void)); +void hv_setup_vmbus_handler(bool (*handler)(void)); void hv_remove_vmbus_handler(void); void hv_setup_stimer0_handler(void (*handler)(void)); void hv_remove_stimer0_handler(void); @@ -188,6 +188,7 @@ void hv_remove_kexec_handler(void); void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)); void hv_remove_crash_handler(void); +extern irqreturn_t vmbus_chan_handler(int irq, void *dev_id); extern void vmbus_irq_mask(struct irq_data *data); extern void vmbus_irq_unmask(struct irq_data *data); extern int vmbus_irq_set_affinity(struct irq_data *data,