From patchwork Mon Jan 8 06:40:54 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: bibo mao X-Patchwork-Id: 13513030 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 55C3F849C; Mon, 8 Jan 2024 06:41:01 +0000 (UTC) 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 _____8CxLOv8mJtlAQwDAA--.9997S3; Mon, 08 Jan 2024 14:41:00 +0800 (CST) Received: from localhost.localdomain (unknown [10.2.5.213]) by localhost.localdomain (Coremail) with SMTP id AQAAf8CxfNz4mJtlNRoHAA--.18591S6; Mon, 08 Jan 2024 14:41:00 +0800 (CST) From: Bibo Mao To: Huacai Chen , Tianrui Zhao , Juergen Gross Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, kvm@vger.kernel.org Subject: [PATCH v2 4/6] LoongArch: Add paravirt interface for guest kernel Date: Mon, 8 Jan 2024 14:40:54 +0800 Message-Id: <20240108064056.232546-5-maobibo@loongson.cn> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20240108064056.232546-1-maobibo@loongson.cn> References: <20240108064056.232546-1-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: AQAAf8CxfNz4mJtlNRoHAA--.18591S6 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBj93XoW3Xw1xuw4fXF48ZF48AF18Zwc_yoW7Zw4Dpa yDAr4kWa1kGFn3A393KrW5ur15Jws7Cry2gFya934FyFsFqF1UXr4vgryqvFyDta1kJay0 gFyrGws0ga1UAabCm3ZEXasCq-sJn29KB7ZKAUJUUUUr529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUU9Fb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r126r13M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AK xVW8Jr0_Cr1UM2kKe7AKxVWUXVWUAwAS0I0E0xvYzxvE52x082IY62kv0487Mc804VCY07 AIYIkI8VC2zVCFFI0UMc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWU tVWrXwAv7VC2z280aVAFwI0_Gr0_Cr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7V AKI48JMxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMxCIbckI1I0E14v2 6r1Y6r17MI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17 CEb7AF67AKxVWUAVWUtwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r4j6ryUMIIF 0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIx AIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2 KfnxnUUI43ZEXa7IU8XyCJUUUUU== 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, and 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 ee123820a476..d8ccaf46a50d 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -564,6 +564,15 @@ 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 d183a745fb85..fa680bdd0bd1 100644 --- a/arch/loongarch/kernel/setup.c +++ b/arch/loongarch/kernel/setup.c @@ -43,6 +43,7 @@ #include #include #include +#include #include #include #include @@ -376,6 +377,7 @@ 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)