From nobody Fri Jun 12 19:58:07 2026 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id C81383314D9; Wed, 13 May 2026 03:13:03 +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=1778641986; cv=none; b=nscUtMp3nlnV5hJLPITZzoBle67wl+0xX3zOXMQFa8HajQKEuOTt8T28N1zHlb+hTbi1hAcMd2TP1eLW7it8sxDYU1C4jid2PMaGcZ91rECiHAZsa9UGE/lGLewOcxA9Yd9eMKFU5t3sSN1ijeouNHrIXzzSWk+90r93tc9gpLA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778641986; c=relaxed/simple; bh=Y4Yrac6ZPe/TgKOOj4TCF7k9yx2DhqGjFqPUAK0TEUU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=ecRvBbnYrsiArhPFRgrEtBjEmcipStsD28QMEcBTM26U6CAjx49hv3x9QEqqAdWGP3jNfjGclXHYso53R0TlBoA+ojVxcZuH1rrzope8wogQqnOziVl1Iu4kJSNtUk1Wum1Yw630vAkQHbDB2PLdmg1T1BvkeoJtrwJz7eouajg= 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 [223.64.68.59]) by gateway (Coremail) with SMTP id _____8DxFOg87ANqjl4JAA--.22618S3; Wed, 13 May 2026 11:13:00 +0800 (CST) Received: from kernelserver (unknown [223.64.68.59]) by front1 (Coremail) with SMTP id qMiowJAxlsA37ANq7M6AAA--.48424S2; Wed, 13 May 2026 11:12:59 +0800 (CST) From: Huacai Chen To: Greg Kroah-Hartman , Sasha Levin , Huacai Chen , Tianrui Zhao , Bibo Mao Cc: Xuerui Wang , stable@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Xianglai Li , Huacai Chen Subject: [PATCH for 6.18] LoongArch: KVM: Compile switch.S directly into the kernel Date: Wed, 13 May 2026 11:12:49 +0800 Message-ID: <20260513031249.2122316-1-chenhuacai@loongson.cn> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: qMiowJAxlsA37ANq7M6AAA--.48424S2 X-CM-SenderInfo: hfkh0x5xdftxo6or00hjvr0hdfq/ X-Coremail-Antispam: 1Uk129KBj93XoW3WF45Ar48ZrW3JF17Cr18CrX_yoWfXF13pa sxArs5tF4rGFn3XryDJ3WDXr98Xw4vgr1I9Fy2y3yrCr129ry5ZF1ktrWDXFy0kw4kJF4F vFyrXwnavFyDJabCm3ZEXasCq-sJn29KB7ZKAUJUUUU5529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUkYb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r106r15M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_JFI_Gr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6r4UJVWxJr1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqjxCEc2xF0cIa020Ex4CE44I27w Aqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JF0_Jw1lYx0Ex4A2jsIE 14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwCF04k20xvY0x 0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E 7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcV C0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Jr0_Gr1lIxAIcVCF 04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7 CjxVAFwI0_Jr0_GrUvcSsGvfC2KfnxnUUI43ZEXa7IU8wNVDUUUUU== Content-Type: text/plain; charset="utf-8" From: Xianglai Li commit 5203012fa6045aac4b69d4e7c212e16dcf38ef10 upstream. If we directly compile the switch.S file into the kernel, the address of the kvm_exc_entry function will definitely be within the DMW memory area. Therefore, we will no longer need to perform a copy relocation of the kvm_exc_entry. So this patch compiles switch.S directly into the kernel, and then remove the copy relocation execution logic for the kvm_exc_entry function. Signed-off-by: Xianglai Li Signed-off-by: Huacai Chen --- arch/loongarch/Kbuild | 2 +- arch/loongarch/include/asm/asm-prototypes.h | 20 ++++++++++++ arch/loongarch/include/asm/kvm_host.h | 3 -- arch/loongarch/kvm/Makefile | 3 +- arch/loongarch/kvm/main.c | 35 ++------------------- arch/loongarch/kvm/switch.S | 20 +++++++++--- 6 files changed, 41 insertions(+), 42 deletions(-) diff --git a/arch/loongarch/Kbuild b/arch/loongarch/Kbuild index beb8499dd8ed..1c7a0dbe5e72 100644 --- a/arch/loongarch/Kbuild +++ b/arch/loongarch/Kbuild @@ -3,7 +3,7 @@ obj-y +=3D mm/ obj-y +=3D net/ obj-y +=3D vdso/ =20 -obj-$(CONFIG_KVM) +=3D kvm/ +obj-$(subst m,y,$(CONFIG_KVM)) +=3D kvm/ =20 # for cleaning subdir- +=3D boot diff --git a/arch/loongarch/include/asm/asm-prototypes.h b/arch/loongarch/i= nclude/asm/asm-prototypes.h index 704066b4f736..de0c17f3f49c 100644 --- a/arch/loongarch/include/asm/asm-prototypes.h +++ b/arch/loongarch/include/asm/asm-prototypes.h @@ -20,3 +20,23 @@ asmlinkage void noinstr __no_stack_protector ret_from_ke= rnel_thread(struct task_ struct pt_regs *regs, int (*fn)(void *), void *fn_arg); + +struct kvm_run; +struct kvm_vcpu; +struct loongarch_fpu; + +void kvm_exc_entry(void); +int kvm_enter_guest(struct kvm_run *run, struct kvm_vcpu *vcpu); + +void kvm_save_fpu(struct loongarch_fpu *fpu); +void kvm_restore_fpu(struct loongarch_fpu *fpu); + +#ifdef CONFIG_CPU_HAS_LSX +void kvm_save_lsx(struct loongarch_fpu *fpu); +void kvm_restore_lsx(struct loongarch_fpu *fpu); +#endif + +#ifdef CONFIG_CPU_HAS_LASX +void kvm_save_lasx(struct loongarch_fpu *fpu); +void kvm_restore_lasx(struct loongarch_fpu *fpu); +#endif diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include= /asm/kvm_host.h index 130cedbb6b39..776bc487a705 100644 --- a/arch/loongarch/include/asm/kvm_host.h +++ b/arch/loongarch/include/asm/kvm_host.h @@ -87,7 +87,6 @@ struct kvm_context { struct kvm_world_switch { int (*exc_entry)(void); int (*enter_guest)(struct kvm_run *run, struct kvm_vcpu *vcpu); - unsigned long page_order; }; =20 #define MAX_PGTABLE_LEVELS 4 @@ -359,8 +358,6 @@ void kvm_exc_entry(void); int kvm_enter_guest(struct kvm_run *run, struct kvm_vcpu *vcpu); =20 extern unsigned long vpid_mask; -extern const unsigned long kvm_exception_size; -extern const unsigned long kvm_enter_guest_size; extern struct kvm_world_switch *kvm_loongarch_ops; =20 #define SW_GCSR (1 << 0) diff --git a/arch/loongarch/kvm/Makefile b/arch/loongarch/kvm/Makefile index ae469edec99c..a4d044da3aa7 100644 --- a/arch/loongarch/kvm/Makefile +++ b/arch/loongarch/kvm/Makefile @@ -7,11 +7,12 @@ include $(srctree)/virt/kvm/Makefile.kvm =20 obj-$(CONFIG_KVM) +=3D kvm.o =20 +obj-y +=3D switch.o + kvm-y +=3D exit.o kvm-y +=3D interrupt.o kvm-y +=3D main.o kvm-y +=3D mmu.o -kvm-y +=3D switch.o kvm-y +=3D timer.o kvm-y +=3D tlb.o kvm-y +=3D vcpu.o diff --git a/arch/loongarch/kvm/main.c b/arch/loongarch/kvm/main.c index a75c9b9e53ff..24553fe34979 100644 --- a/arch/loongarch/kvm/main.c +++ b/arch/loongarch/kvm/main.c @@ -348,8 +348,7 @@ void kvm_arch_disable_virtualization_cpu(void) =20 static int kvm_loongarch_env_init(void) { - int cpu, order, ret; - void *addr; + int cpu, ret; struct kvm_context *context; =20 vmcs =3D alloc_percpu(struct kvm_context); @@ -365,30 +364,8 @@ static int kvm_loongarch_env_init(void) return -ENOMEM; } =20 - /* - * PGD register is shared between root kernel and kvm hypervisor. - * So world switch entry should be in DMW area rather than TLB area - * to avoid page fault reenter. - * - * In future if hardware pagetable walking is supported, we won't - * need to copy world switch code to DMW area. - */ - order =3D get_order(kvm_exception_size + kvm_enter_guest_size); - addr =3D (void *)__get_free_pages(GFP_KERNEL, order); - if (!addr) { - free_percpu(vmcs); - vmcs =3D NULL; - kfree(kvm_loongarch_ops); - kvm_loongarch_ops =3D NULL; - return -ENOMEM; - } - - memcpy(addr, kvm_exc_entry, kvm_exception_size); - memcpy(addr + kvm_exception_size, kvm_enter_guest, kvm_enter_guest_size); - flush_icache_range((unsigned long)addr, (unsigned long)addr + kvm_excepti= on_size + kvm_enter_guest_size); - kvm_loongarch_ops->exc_entry =3D addr; - kvm_loongarch_ops->enter_guest =3D addr + kvm_exception_size; - kvm_loongarch_ops->page_order =3D order; + kvm_loongarch_ops->exc_entry =3D (void *)kvm_exc_entry; + kvm_loongarch_ops->enter_guest =3D (void *)kvm_enter_guest; =20 vpid_mask =3D read_csr_gstat(); vpid_mask =3D (vpid_mask & CSR_GSTAT_GIDBIT) >> CSR_GSTAT_GIDBIT_SHIFT; @@ -428,16 +405,10 @@ static int kvm_loongarch_env_init(void) =20 static void kvm_loongarch_env_exit(void) { - unsigned long addr; - if (vmcs) free_percpu(vmcs); =20 if (kvm_loongarch_ops) { - if (kvm_loongarch_ops->exc_entry) { - addr =3D (unsigned long)kvm_loongarch_ops->exc_entry; - free_pages(addr, kvm_loongarch_ops->page_order); - } kfree(kvm_loongarch_ops); } =20 diff --git a/arch/loongarch/kvm/switch.S b/arch/loongarch/kvm/switch.S index f1768b7a6194..6fa5928b3ca6 100644 --- a/arch/loongarch/kvm/switch.S +++ b/arch/loongarch/kvm/switch.S @@ -4,9 +4,11 @@ */ =20 #include +#include #include #include #include +#include #include #include =20 @@ -100,8 +102,13 @@ * - is still in guest mode, such as pgd table/vmid registers etc, * - will fix with hw page walk enabled in future * load kvm_vcpu from reserved CSR KVM_VCPU_KS, and save a2 to KVM_TEMP_KS + * + * PGD register is shared between root kernel and kvm hypervisor. + * So world switch entry should be in DMW area rather than TLB area + * to avoid page fault re-enter. */ .text + .p2align PAGE_SHIFT .cfi_sections .debug_frame SYM_CODE_START(kvm_exc_entry) UNWIND_HINT_UNDEFINED @@ -190,8 +197,8 @@ ret_to_host: kvm_restore_host_gpr a2 jr ra =20 -SYM_INNER_LABEL(kvm_exc_entry_end, SYM_L_LOCAL) SYM_CODE_END(kvm_exc_entry) +EXPORT_SYMBOL_GPL(kvm_exc_entry) =20 /* * int kvm_enter_guest(struct kvm_run *run, struct kvm_vcpu *vcpu) @@ -215,8 +222,8 @@ SYM_FUNC_START(kvm_enter_guest) /* Save kvm_vcpu to kscratch */ csrwr a1, KVM_VCPU_KS kvm_switch_to_guest -SYM_INNER_LABEL(kvm_enter_guest_end, SYM_L_LOCAL) SYM_FUNC_END(kvm_enter_guest) +EXPORT_SYMBOL_GPL(kvm_enter_guest) =20 SYM_FUNC_START(kvm_save_fpu) fpu_save_csr a0 t1 @@ -224,6 +231,7 @@ SYM_FUNC_START(kvm_save_fpu) fpu_save_cc a0 t1 t2 jr ra SYM_FUNC_END(kvm_save_fpu) +EXPORT_SYMBOL_GPL(kvm_save_fpu) =20 SYM_FUNC_START(kvm_restore_fpu) fpu_restore_double a0 t1 @@ -231,6 +239,7 @@ SYM_FUNC_START(kvm_restore_fpu) fpu_restore_cc a0 t1 t2 jr ra SYM_FUNC_END(kvm_restore_fpu) +EXPORT_SYMBOL_GPL(kvm_restore_fpu) =20 #ifdef CONFIG_CPU_HAS_LSX SYM_FUNC_START(kvm_save_lsx) @@ -239,6 +248,7 @@ SYM_FUNC_START(kvm_save_lsx) lsx_save_data a0 t1 jr ra SYM_FUNC_END(kvm_save_lsx) +EXPORT_SYMBOL_GPL(kvm_save_lsx) =20 SYM_FUNC_START(kvm_restore_lsx) lsx_restore_data a0 t1 @@ -246,6 +256,7 @@ SYM_FUNC_START(kvm_restore_lsx) fpu_restore_csr a0 t1 t2 jr ra SYM_FUNC_END(kvm_restore_lsx) +EXPORT_SYMBOL_GPL(kvm_restore_lsx) #endif =20 #ifdef CONFIG_CPU_HAS_LASX @@ -255,6 +266,7 @@ SYM_FUNC_START(kvm_save_lasx) lasx_save_data a0 t1 jr ra SYM_FUNC_END(kvm_save_lasx) +EXPORT_SYMBOL_GPL(kvm_save_lasx) =20 SYM_FUNC_START(kvm_restore_lasx) lasx_restore_data a0 t1 @@ -262,10 +274,8 @@ SYM_FUNC_START(kvm_restore_lasx) fpu_restore_csr a0 t1 t2 jr ra SYM_FUNC_END(kvm_restore_lasx) +EXPORT_SYMBOL_GPL(kvm_restore_lasx) #endif - .section ".rodata" -SYM_DATA(kvm_exception_size, .quad kvm_exc_entry_end - kvm_exc_entry) -SYM_DATA(kvm_enter_guest_size, .quad kvm_enter_guest_end - kvm_enter_guest) =20 #ifdef CONFIG_CPU_HAS_LBT STACK_FRAME_NON_STANDARD kvm_restore_fpu --=20 2.52.0