From patchwork Mon Jan 22 10:03:11 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: bibo mao X-Patchwork-Id: 13525094 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 0DA8B3A1AF; Mon, 22 Jan 2024 10:03:17 +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=1705917800; cv=none; b=lLqrIrut070LKfd4wZsHuPBk8+r//mefI5TpKBxFxSxIw247FMS++ajDXuCLL9U9gwz00KJ/DJlT5fLwLYlxodIbi9LN8L5YkLHFzygFj4H78OGkvDoEmoVlO9YPM3cwP8tv4mVVvCy9SDAZY6QZnCa1+oyLVeBajHcNzeraHaI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705917800; c=relaxed/simple; bh=oX3UZrXbFCYjp7Sd2ezOWu17XMWgSh8cbu5vdDCfPzQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=dt4J+3wc1tS4j0f4+O4qO1qefQLdBI8/zb4q/BuefgcRV3bPUdF4RIqW/LG5lOA4yyWLPH1k64RnMAtHZ5fkTaUZklUg0fzrqpq32te0eSd4VhHg4mGYme4RjeG301CH0D29vs/OLqC0mli4LuhZSJHzL5uj6nsCpB5Smm2l4Hc= 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+tkPa5lBYQDAA--.14313S3; Mon, 22 Jan 2024 18:03:16 +0800 (CST) Received: from localhost.localdomain (unknown [10.2.5.213]) by localhost.localdomain (Coremail) with SMTP id AQAAf8BxXs1hPa5l52oRAA--.11303S6; Mon, 22 Jan 2024 18:03:15 +0800 (CST) From: Bibo Mao To: Huacai Chen , Tianrui Zhao , Juergen Gross , Paolo Bonzini Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, kvm@vger.kernel.org Subject: [PATCH v3 4/6] LoongArch: Add paravirt interface for guest kernel Date: Mon, 22 Jan 2024 18:03:11 +0800 Message-Id: <20240122100313.1589372-5-maobibo@loongson.cn> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20240122100313.1589372-1-maobibo@loongson.cn> References: <20240122100313.1589372-1-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: AQAAf8BxXs1hPa5l52oRAA--.11303S6 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBj93XoW3Xw1xuw4fXF48ZF48AF18Zwc_yoW7ur1Upa 4DAr4kWa1kGFn3A393KrWY9r15Jws7Cry2gFy3u34FyFsFqF1UXr4vgryqvFyDta1kJay0 gFyrGws0ga1UJabCm3ZEXasCq-sJn29KB7ZKAUJUUUU7529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUBIb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AK xVW8Jr0_Cr1UM2kKe7AKxVWUXVWUAwAS0I0E0xvYzxvE52x082IY62kv0487Mc804VCY07 AIYIkI8VC2zVCFFI0UMc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWU tVWrXwAv7VC2z280aVAFwI0_Gr0_Cr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7V AKI48JMxkF7I0En4kS14v26r126r1DMxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY 6r1j6r4UMxCIbckI1I0E14v26r1Y6r17MI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7 xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY6xII jxv20xvE14v26ryj6F1UMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAIw2 0EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aVCY1x02 67AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU0epB3UUUUU== The patch add paravirt interface for guest kernel, function pv_guest_init firstly checks whether system runs on VM mode. If kernel runs on VM mode, it will call function kvm_para_available to detect whether current VMM is KVM hypervisor. And the paravirt function can work only if current VMM is KVM hypervisor, since there is only KVM hypervisor supported on LoongArch now. Signed-off-by: Bibo Mao --- arch/loongarch/Kconfig | 9 ++++ arch/loongarch/include/asm/kvm_para.h | 7 ++++ arch/loongarch/include/asm/paravirt.h | 27 ++++++++++++ .../include/asm/paravirt_api_clock.h | 1 + arch/loongarch/kernel/Makefile | 1 + arch/loongarch/kernel/paravirt.c | 41 +++++++++++++++++++ arch/loongarch/kernel/setup.c | 2 + 7 files changed, 88 insertions(+) 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 10959e6c3583..817a56dff80f 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -585,6 +585,15 @@ 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/kvm_para.h b/arch/loongarch/include/asm/kvm_para.h index 9425d3b7e486..41200e922a82 100644 --- a/arch/loongarch/include/asm/kvm_para.h +++ b/arch/loongarch/include/asm/kvm_para.h @@ -2,6 +2,13 @@ #ifndef _ASM_LOONGARCH_KVM_PARA_H #define _ASM_LOONGARCH_KVM_PARA_H +/* + * Hypcall code field + */ +#define HYPERVISOR_KVM 1 +#define HYPERVISOR_VENDOR_SHIFT 8 +#define HYPERCALL_CODE(vendor, code) ((vendor << HYPERVISOR_VENDOR_SHIFT) + code) + /* * LoongArch hypcall return code */ diff --git a/arch/loongarch/include/asm/paravirt.h b/arch/loongarch/include/asm/paravirt.h new file mode 100644 index 000000000000..b64813592ba0 --- /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_guest_init(void); +#else +static inline int pv_guest_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/paravirt.c b/arch/loongarch/kernel/paravirt.c new file mode 100644 index 000000000000..21d01d05791a --- /dev/null +++ b/arch/loongarch/kernel/paravirt.c @@ -0,0 +1,41 @@ +// SPDX-License-Identifier: GPL-2.0 +#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); + +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_guest_init(void) +{ + if (!cpu_has_hypervisor) + return 0; + if (!kvm_para_available()) + return 0; + + return 1; +} diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c index edf2bba80130..de5c36dccc49 100644 --- a/arch/loongarch/kernel/setup.c +++ b/arch/loongarch/kernel/setup.c @@ -43,6 +43,7 @@ #include #include #include +#include #include #include #include @@ -367,6 +368,7 @@ void __init platform_init(void) pr_info("The BIOS Version: %s\n", b_info.bios_version); efi_runtime_init(); + pv_guest_init(); } static void __init check_kernel_sections_mem(void)