From patchwork Sat Mar 2 08:25:31 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bibo Mao X-Patchwork-Id: 13579491 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id DA1A818659; Sat, 2 Mar 2024 08:25:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.242.206.163 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709367946; cv=none; b=OyqRGvo3cGT6z1l+dlPaBNRCy16iblgdPdUg9VTHz7+6xjjnceRu3hhAw8j8DeSITIWVCM2er2sWZnfc1E23sWkAsnvtrNn3U/GdVvp94UqUTeTH/xUcR5dD1JR/mFDw99loeuNpfc1AXSsM5fEdvrj13YHBlpe1tnwoIGkKot4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709367946; c=relaxed/simple; bh=YS030k40TsaKC7Al33RIXoNq0zRM2Jnh7Pw8VJbAxpQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=SyrbqMQo3MnYGwyU5GVyB3mYi3fTf7o89nLY3LtMkkeBP8g+75SaL4b7Gmi/5YK8IYEagkMwvS1CjpCzbZA+qYARtAi51R+35jVVHmHutlZYETML87WErEEO6tFGk+OZCYzHUfPyh6JyFZ2wYXjF9+HDvL81OD+1SbP5d14H9e0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn; spf=pass smtp.mailfrom=loongson.cn; arc=none smtp.client-ip=114.242.206.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=loongson.cn Received: from loongson.cn (unknown [10.2.5.213]) by gateway (Coremail) with SMTP id _____8Bx3+uG4uJlMIoTAA--.49263S3; Sat, 02 Mar 2024 16:25:42 +0800 (CST) Received: from localhost.localdomain (unknown [10.2.5.213]) by localhost.localdomain (Coremail) with SMTP id AQAAf8CxLBN84uJlqlhMAA--.6847S8; Sat, 02 Mar 2024 16:25:41 +0800 (CST) From: Bibo Mao To: Huacai Chen , Tianrui Zhao , Juergen Gross , Paolo Bonzini , Jonathan Corbet Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, kvm@vger.kernel.org Subject: [PATCH v6 6/7] LoongArch: Add pv ipi support on guest kernel side Date: Sat, 2 Mar 2024 16:25:31 +0800 Message-Id: <20240302082532.1415200-7-maobibo@loongson.cn> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20240302082532.1415200-1-maobibo@loongson.cn> References: <20240302082532.1415200-1-maobibo@loongson.cn> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: AQAAf8CxLBN84uJlqlhMAA--.6847S8 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBj93XoW3Zr1UZw4kZF4fKFWUGF1Dtwc_yoWDXw1DpF ZrAr1kWr4rGFn7A395G395ur15J3s7Cw12q3W7AFyrAFsFqF15Xr4kKFyqqFy8ta97Ga4F gF95Gr4qga1UAabCm3ZEXasCq-sJn29KB7ZKAUJUUUUx529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUBmb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Cr0_Gr1UM28EF7xvwVC2z280aVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIEc7CjxVAF wI0_Gr1j6F4UJwAaw2AFwI0_JF0_Jw1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqjxCEc2 xF0cIa020Ex4CE44I27wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_ Wrv_ZF1lYx0Ex4A2jsIE14v26F4j6r4UJwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2 Ij64vIr41lc7CjxVAaw2AFwI0_JF0_Jw1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Y z7v_Jr0_Gr1l4IxYO2xFxVAFwI0_JF0_Jw1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x 8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE 2Ix0cI8IcVAFwI0_Ar0_tr1lIxAIcVC0I7IYx2IY6xkF7I0E14v26F4j6r4UJwCI42IY6x AIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Cr0_Gr1UMIIF0xvEx4A2jsIE c7CjxVAFwI0_Gr1j6F4UJbIYCTnIWIevJa73UjIFyTuYvjxUI0eHUUUUU PARAVIRT option and pv ipi is added on guest kernel side, function pv_ipi_init() is to add ipi sending and ipi receiving hooks. This function firstly checks whether system runs on VM mode. If kernel runs on VM mode, it will call function kvm_para_available() to detect current hypervirsor type. Now only KVM type detection is supported, the paravirt function can work only if current hypervisor type is KVM, since there is only KVM supported on LoongArch now. PV IPI uses virtual IPI sender and virtual IPI receiver function. With virutal IPI sender, ipi message is stored in DDR memory rather than emulated HW. IPI multicast is supported, and 128 vcpus can received IPIs at the same time like X86 KVM method. Hypercall method is used for IPI sending. With virtual IPI receiver, HW SW0 is used rather than real IPI HW. Since VCPU has separate HW SW0 like HW timer, there is no trap in IPI interrupt acknowledge. And IPI message is stored in DDR, no trap in get IPI message. Signed-off-by: Bibo Mao --- arch/loongarch/Kconfig | 9 ++ arch/loongarch/include/asm/hardirq.h | 1 + arch/loongarch/include/asm/paravirt.h | 27 ++++ .../include/asm/paravirt_api_clock.h | 1 + arch/loongarch/kernel/Makefile | 1 + arch/loongarch/kernel/irq.c | 2 +- arch/loongarch/kernel/paravirt.c | 151 ++++++++++++++++++ arch/loongarch/kernel/smp.c | 4 +- 8 files changed, 194 insertions(+), 2 deletions(-) create mode 100644 arch/loongarch/include/asm/paravirt.h create mode 100644 arch/loongarch/include/asm/paravirt_api_clock.h create mode 100644 arch/loongarch/kernel/paravirt.c diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index 929f68926b34..fdaae9a0435c 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -587,6 +587,15 @@ config CPU_HAS_PREFETCH bool default y +config PARAVIRT + bool "Enable paravirtualization code" + depends on AS_HAS_LVZ_EXTENSION + help + This changes the kernel so it can modify itself when it is run + under a hypervisor, potentially improving performance significantly + over full virtualization. However, when run without a hypervisor + the kernel is theoretically slower and slightly larger. + config ARCH_SUPPORTS_KEXEC def_bool y diff --git a/arch/loongarch/include/asm/hardirq.h b/arch/loongarch/include/asm/hardirq.h index 9f0038e19c7f..b26d596a73aa 100644 --- a/arch/loongarch/include/asm/hardirq.h +++ b/arch/loongarch/include/asm/hardirq.h @@ -21,6 +21,7 @@ enum ipi_msg_type { typedef struct { unsigned int ipi_irqs[NR_IPI]; unsigned int __softirq_pending; + atomic_t message ____cacheline_aligned_in_smp; } ____cacheline_aligned irq_cpustat_t; DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat); diff --git a/arch/loongarch/include/asm/paravirt.h b/arch/loongarch/include/asm/paravirt.h new file mode 100644 index 000000000000..58f7b7b89f2c --- /dev/null +++ b/arch/loongarch/include/asm/paravirt.h @@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_LOONGARCH_PARAVIRT_H +#define _ASM_LOONGARCH_PARAVIRT_H + +#ifdef CONFIG_PARAVIRT +#include +struct static_key; +extern struct static_key paravirt_steal_enabled; +extern struct static_key paravirt_steal_rq_enabled; + +u64 dummy_steal_clock(int cpu); +DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock); + +static inline u64 paravirt_steal_clock(int cpu) +{ + return static_call(pv_steal_clock)(cpu); +} + +int pv_ipi_init(void); +#else +static inline int pv_ipi_init(void) +{ + return 0; +} + +#endif // CONFIG_PARAVIRT +#endif diff --git a/arch/loongarch/include/asm/paravirt_api_clock.h b/arch/loongarch/include/asm/paravirt_api_clock.h new file mode 100644 index 000000000000..65ac7cee0dad --- /dev/null +++ b/arch/loongarch/include/asm/paravirt_api_clock.h @@ -0,0 +1 @@ +#include diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile index 3c808c680370..662e6e9de12d 100644 --- a/arch/loongarch/kernel/Makefile +++ b/arch/loongarch/kernel/Makefile @@ -48,6 +48,7 @@ obj-$(CONFIG_MODULES) += module.o module-sections.o obj-$(CONFIG_STACKTRACE) += stacktrace.o obj-$(CONFIG_PROC_FS) += proc.o +obj-$(CONFIG_PARAVIRT) += paravirt.o obj-$(CONFIG_SMP) += smp.o diff --git a/arch/loongarch/kernel/irq.c b/arch/loongarch/kernel/irq.c index ce36897d1e5a..4863e6c1b739 100644 --- a/arch/loongarch/kernel/irq.c +++ b/arch/loongarch/kernel/irq.c @@ -113,5 +113,5 @@ void __init init_IRQ(void) per_cpu(irq_stack, i), per_cpu(irq_stack, i) + IRQ_STACK_SIZE); } - set_csr_ecfg(ECFGF_IP0 | ECFGF_IP1 | ECFGF_IP2 | ECFGF_IPI | ECFGF_PMC); + set_csr_ecfg(ECFGF_SIP0 | ECFGF_IP0 | ECFGF_IP1 | ECFGF_IP2 | ECFGF_IPI | ECFGF_PMC); } diff --git a/arch/loongarch/kernel/paravirt.c b/arch/loongarch/kernel/paravirt.c new file mode 100644 index 000000000000..9044ed62045c --- /dev/null +++ b/arch/loongarch/kernel/paravirt.c @@ -0,0 +1,151 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include + +struct static_key paravirt_steal_enabled; +struct static_key paravirt_steal_rq_enabled; + +static u64 native_steal_clock(int cpu) +{ + return 0; +} + +DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock); + +#ifdef CONFIG_SMP +static void pv_send_ipi_single(int cpu, unsigned int action) +{ + unsigned int min, old; + irq_cpustat_t *info = &per_cpu(irq_stat, cpu); + + old = atomic_fetch_or(BIT(action), &info->message); + if (old) + return; + + min = cpu_logical_map(cpu); + kvm_hypercall3(KVM_HCALL_FUNC_PV_IPI, 1, 0, min); +} + +#define KVM_IPI_CLUSTER_SIZE (2 * BITS_PER_LONG) +static void pv_send_ipi_mask(const struct cpumask *mask, unsigned int action) +{ + unsigned int cpu, i, min = 0, max = 0, old; + __uint128_t bitmap = 0; + irq_cpustat_t *info; + + if (cpumask_empty(mask)) + return; + + action = BIT(action); + for_each_cpu(i, mask) { + info = &per_cpu(irq_stat, i); + old = atomic_fetch_or(action, &info->message); + if (old) + continue; + + cpu = cpu_logical_map(i); + if (!bitmap) { + min = max = cpu; + } else if (cpu > min && cpu < min + KVM_IPI_CLUSTER_SIZE) { + max = cpu > max ? cpu : max; + } else if (cpu < min && (max - cpu) < KVM_IPI_CLUSTER_SIZE) { + bitmap <<= min - cpu; + min = cpu; + } else { + /* + * Physical cpuid is sorted in ascending order ascend + * for the next mask calculation, send IPI here + * directly and skip the remainding cpus + */ + kvm_hypercall3(KVM_HCALL_FUNC_PV_IPI, + (unsigned long)bitmap, + (unsigned long)(bitmap >> BITS_PER_LONG), min); + min = max = cpu; + bitmap = 0; + } + __set_bit(cpu - min, (unsigned long *)&bitmap); + } + + if (bitmap) + kvm_hypercall3(KVM_HCALL_FUNC_PV_IPI, (unsigned long)bitmap, + (unsigned long)(bitmap >> BITS_PER_LONG), min); +} + +static irqreturn_t loongson_do_swi(int irq, void *dev) +{ + irq_cpustat_t *info; + long action; + + /* Clear swi interrupt */ + clear_csr_estat(1 << INT_SWI0); + info = this_cpu_ptr(&irq_stat); + action = atomic_xchg(&info->message, 0); + if (action & SMP_CALL_FUNCTION) { + generic_smp_call_function_interrupt(); + info->ipi_irqs[IPI_CALL_FUNCTION]++; + } + + if (action & SMP_RESCHEDULE) { + scheduler_ipi(); + info->ipi_irqs[IPI_RESCHEDULE]++; + } + + return IRQ_HANDLED; +} + +static void pv_init_ipi(void) +{ + int r, swi0; + + swi0 = get_percpu_irq(INT_SWI0); + if (swi0 < 0) + panic("SWI0 IRQ mapping failed\n"); + irq_set_percpu_devid(swi0); + r = request_percpu_irq(swi0, loongson_do_swi, "SWI0", &irq_stat); + if (r < 0) + panic("SWI0 IRQ request failed\n"); +} +#endif + +static bool kvm_para_available(void) +{ + static int hypervisor_type; + int config; + + if (!hypervisor_type) { + config = read_cpucfg(CPUCFG_KVM_SIG); + if (!memcmp(&config, KVM_SIGNATURE, 4)) + hypervisor_type = HYPERVISOR_KVM; + } + + return hypervisor_type == HYPERVISOR_KVM; +} + +int __init pv_ipi_init(void) +{ + int feature; + + if (!cpu_has_hypervisor) + return 0; + if (!kvm_para_available()) + return 0; + + /* + * check whether KVM hypervisor supports pv_ipi or not + */ + feature = read_cpucfg(CPUCFG_KVM_FEATURE); +#ifdef CONFIG_SMP + if (feature & KVM_FEATURE_PV_IPI) { + smp_ops.init_ipi = pv_init_ipi; + smp_ops.send_ipi_single = pv_send_ipi_single; + smp_ops.send_ipi_mask = pv_send_ipi_mask; + } +#endif + + return 1; +} diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c index 1fce775be4f6..9eff7aa4c552 100644 --- a/arch/loongarch/kernel/smp.c +++ b/arch/loongarch/kernel/smp.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include #include @@ -309,6 +310,7 @@ void __init loongson_smp_setup(void) cpu_data[0].core = cpu_logical_map(0) % loongson_sysconf.cores_per_package; cpu_data[0].package = cpu_logical_map(0) / loongson_sysconf.cores_per_package; + pv_ipi_init(); iocsr_write32(0xffffffff, LOONGARCH_IOCSR_IPI_EN); pr_info("Detected %i available CPU(s)\n", loongson_sysconf.nr_cpus); } @@ -352,7 +354,7 @@ void loongson_boot_secondary(int cpu, struct task_struct *idle) void loongson_init_secondary(void) { unsigned int cpu = smp_processor_id(); - unsigned int imask = ECFGF_IP0 | ECFGF_IP1 | ECFGF_IP2 | + unsigned int imask = ECFGF_SIP0 | ECFGF_IP0 | ECFGF_IP1 | ECFGF_IP2 | ECFGF_IPI | ECFGF_PMC | ECFGF_TIMER; change_csr_ecfg(ECFG0_IM, imask);