From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 4AEBCDDDC; Mon, 26 Feb 2024 02:27:44 +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=1708914469; cv=none; b=hxzlR97gCsyOf7VtGNSlZJUKnAXxNXpFT+HRXm+I4B86LTKGVYK9pe0gPi6JaUBXIMMVOH9fR0OeG80CPRTQ+m5g/WNmU8FKIdG1t0jSYDJusP1Mv5WsEVdAnEwOh4TpjsM6185OycbAI5cq0GQqfnVtfz0kr0r7x8tei6C32Y8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708914469; c=relaxed/simple; bh=3BPVpZmd3r2/6e9QRzJoUxZLCVM8tqHO5vRHJrJNW7c=; h=Subject:To:Cc:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=cmVCzmSDDUvfSQlbRoMdTzk2CqtGO3G+wbcrytePcYZRFJGvdONFMsEvWjbS5V0QMqzyISDxwFT2jk7zUYv2nwkMM09Rx2mb61ry8ZkLbMDMUoHE5APH2Zn0fqach6onjRQ6VkvuUChGT2qUuon4ONiNTX7q3q9iAVk2FRtQO4w= 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 [10.20.42.173]) by gateway (Coremail) with SMTP id _____8Dx6ugf99tlfWgRAA--.24810S3; Mon, 26 Feb 2024 10:27:43 +0800 (CST) Received: from [10.20.42.173] (unknown [10.20.42.173]) by localhost.localdomain (Coremail) with SMTP id AQAAf8AxRMwa99tlniVEAA--.39424S3; Mon, 26 Feb 2024 10:27:40 +0800 (CST) Subject: Re: [PATCH v5 4/6] LoongArch: Add paravirt interface for guest kernel To: Huacai Chen Cc: Tianrui Zhao , Juergen Gross , Paolo Bonzini , loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, kvm@vger.kernel.org References: <20240222032803.2177856-1-maobibo@loongson.cn> <20240222032803.2177856-5-maobibo@loongson.cn> From: maobibo Message-ID: <6bf79c0f-daf3-9077-e83f-38bcfd7282e3@loongson.cn> Date: Mon, 26 Feb 2024 10:27:37 +0800 User-Agent: Mozilla/5.0 (X11; Linux loongarch64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-CM-TRANSID:AQAAf8AxRMwa99tlniVEAA--.39424S3 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBj93XoWxKF15Gr13uF45Kr48Gw1kCrX_yoWxWr13pa 4DAF4kGa18GryxAr9IqrZxurn8J397Gr129Fy2va4FyFZFvr1UJr1vgryq9Fykta1kJ3W0 gFyrWw1a9a15tagCm3ZEXasCq-sJn29KB7ZKAUJUUUU7529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUP2b4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Gr0_Xr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6r4j6r4UJwAaw2AFwI0_Jrv_JF1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqjxCEc2xF0c Ia020Ex4CE44I27wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JF0_ Jw1lYx0Ex4A2jsIE14v26r4j6F4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvEwIxGrw CYjI0SjxkI62AI1cAE67vIY487MxkF7I0En4kS14v26r126r1DMxAIw28IcxkI7VAKI48J MxC20s026xCaFVCjc4AY6r1j6r4UMxCIbckI1I0E14v26r1Y6r17MI8I3I0E5I8CrVAFwI 0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y 0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxV WUJVW8JwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1l IxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU0b6pPUUUU U== On 2024/2/24 下午5:15, Huacai Chen wrote: > Hi, Bibo, > > On Thu, Feb 22, 2024 at 11:28 AM Bibo Mao wrote: >> >> Paravirt interface pv_ipi_init() is added here for guest kernel, it >> firstly checks whether system runs on VM mode. If kernel runs on VM mode, >> it will call function kvm_para_available() to detect current VMM type. >> Now only KVM VMM type is detected,the paravirt function can work only if >> current VMM is KVM hypervisor, since there is only KVM hypervisor >> supported on LoongArch now. >> >> There is not effective with pv_ipi_init() now, it is dummy function. >> >> 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 | 1 + >> 7 files changed, 87 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 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/kvm_para.h b/arch/loongarch/include/asm/kvm_para.h >> index d48f993ae206..af5d677a9052 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 >> >> +/* >> + * Hypercall code field >> + */ >> +#define HYPERVISOR_KVM 1 >> +#define HYPERVISOR_VENDOR_SHIFT 8 >> +#define HYPERCALL_CODE(vendor, code) ((vendor << HYPERVISOR_VENDOR_SHIFT) + code) >> + >> /* >> * LoongArch hypercall return code >> */ >> 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/paravirt.c b/arch/loongarch/kernel/paravirt.c >> new file mode 100644 >> index 000000000000..5cf794e8490f >> --- /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_ipi_init(void) >> +{ >> + if (!cpu_has_hypervisor) >> + return 0; >> + if (!kvm_para_available()) >> + return 0; >> + >> + return 1; >> +} > pv_ipi_init() and its declaration should also be moved to the last > patch. And if you think this patch is too small, you can squash the > whole patch to the last one. I can move the whole patch to the last one. I do not think that is is reasonable to move function pv_ipi_init() to the last patch. Regards Bibo Mao > > Huacai > >> diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c >> index edf2bba80130..b79a1244b56f 100644 >> --- a/arch/loongarch/kernel/setup.c >> +++ b/arch/loongarch/kernel/setup.c >> @@ -43,6 +43,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> -- >> 2.39.3 >>