From nobody Wed Dec 17 14:36:47 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7365AC4167B for ; Mon, 30 Oct 2023 14:25:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233689AbjJ3OZ2 (ORCPT ); Mon, 30 Oct 2023 10:25:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233684AbjJ3OZV (ORCPT ); Mon, 30 Oct 2023 10:25:21 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 71DD4C6; Mon, 30 Oct 2023 07:25:18 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 28EF721CB2; Mon, 30 Oct 2023 14:25:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1698675917; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WQOy6pmGVsZoJQWqUvwRPY1Vmq8EiP0giPaU8rw9TWY=; b=UD3xyMMK5QDTRrRGkaPCZjE3QkmKPaiSnNPA5nn6CRBP3ZYocQuzXIyjlmq73f8u+6RltH XK3YHJT+Zrs88ia2k4I7whPdRSN7E9IbPfsn/Twk8IH+uJS7+P8+hxZrKtP6N4SLolTTco A+3hRY3ZHkW6eSD6eQFhX6nbhkss8as= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 9E728138F8; Mon, 30 Oct 2023 14:25:16 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 2AdUJcy8P2XEQAAAMHmgww (envelope-from ); Mon, 30 Oct 2023 14:25:16 +0000 From: Juergen Gross To: linux-kernel@vger.kernel.org, x86@kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org Cc: Juergen Gross , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Ajay Kaher , Alexey Makhalov , VMware PV-Drivers Reviewers , Paolo Bonzini , Wanpeng Li , Vitaly Kuznetsov , Boris Ostrovsky , xen-devel@lists.xenproject.org Subject: [PATCH v4 1/5] x86/paravirt: move some functions and defines to alternative Date: Mon, 30 Oct 2023 15:25:04 +0100 Message-Id: <20231030142508.1407-2-jgross@suse.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20231030142508.1407-1-jgross@suse.com> References: <20231030142508.1407-1-jgross@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" As a preparation for replacing paravirt patching completely by alternative patching, move some backend functions and #defines to alternative code and header. Signed-off-by: Juergen Gross --- V4: - rename x86_nop() to nop_func() and x86_BUG() to BUG_func() (Boris Petkov) --- arch/x86/include/asm/alternative.h | 16 ++++++++++++ arch/x86/include/asm/paravirt.h | 12 --------- arch/x86/include/asm/paravirt_types.h | 4 +-- arch/x86/include/asm/qspinlock_paravirt.h | 4 +-- arch/x86/kernel/alternative.c | 10 ++++++++ arch/x86/kernel/kvm.c | 4 +-- arch/x86/kernel/paravirt.c | 30 +++++++---------------- arch/x86/xen/irq.c | 2 +- 8 files changed, 41 insertions(+), 41 deletions(-) diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alte= rnative.h index 9c4da699e11a..484f16dfc429 100644 --- a/arch/x86/include/asm/alternative.h +++ b/arch/x86/include/asm/alternative.h @@ -330,6 +330,22 @@ static inline int alternatives_text_reserved(void *sta= rt, void *end) */ #define ASM_NO_INPUT_CLOBBER(clbr...) "i" (0) : clbr =20 +/* Macro for creating assembler functions avoiding any C magic. */ +#define DEFINE_ASM_FUNC(func, instr, sec) \ + asm (".pushsection " #sec ", \"ax\"\n" \ + ".global " #func "\n\t" \ + ".type " #func ", @function\n\t" \ + ASM_FUNC_ALIGN "\n" \ + #func ":\n\t" \ + ASM_ENDBR \ + instr "\n\t" \ + ASM_RET \ + ".size " #func ", . - " #func "\n\t" \ + ".popsection") + +void BUG_func(void); +void nop_func(void); + #else /* __ASSEMBLY__ */ =20 #ifdef CONFIG_SMP diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravir= t.h index 6c8ff12140ae..ed5c7342f2ef 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -726,18 +726,6 @@ static __always_inline unsigned long arch_local_irq_sa= ve(void) #undef PVOP_VCALL4 #undef PVOP_CALL4 =20 -#define DEFINE_PARAVIRT_ASM(func, instr, sec) \ - asm (".pushsection " #sec ", \"ax\"\n" \ - ".global " #func "\n\t" \ - ".type " #func ", @function\n\t" \ - ASM_FUNC_ALIGN "\n" \ - #func ":\n\t" \ - ASM_ENDBR \ - instr "\n\t" \ - ASM_RET \ - ".size " #func ", . - " #func "\n\t" \ - ".popsection") - extern void default_banner(void); void native_pv_lock_init(void) __init; =20 diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/p= aravirt_types.h index 772d03487520..c3d680544da1 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -542,8 +542,6 @@ int paravirt_disable_iospace(void); __PVOP_VCALL(op, PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \ PVOP_CALL_ARG3(arg3), PVOP_CALL_ARG4(arg4)) =20 -void _paravirt_nop(void); -void paravirt_BUG(void); unsigned long paravirt_ret0(void); #ifdef CONFIG_PARAVIRT_XXL u64 _paravirt_ident_64(u64); @@ -553,7 +551,7 @@ void pv_native_irq_enable(void); unsigned long pv_native_read_cr2(void); #endif =20 -#define paravirt_nop ((void *)_paravirt_nop) +#define paravirt_nop ((void *)nop_func) =20 extern struct paravirt_patch_site __parainstructions[], __parainstructions_end[]; diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/a= sm/qspinlock_paravirt.h index 85b6e3609cb9..ef9697f20129 100644 --- a/arch/x86/include/asm/qspinlock_paravirt.h +++ b/arch/x86/include/asm/qspinlock_paravirt.h @@ -56,8 +56,8 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowp= ath, ".spinlock.text"); "pop %rdx\n\t" \ FRAME_END =20 -DEFINE_PARAVIRT_ASM(__raw_callee_save___pv_queued_spin_unlock, - PV_UNLOCK_ASM, .spinlock.text); +DEFINE_ASM_FUNC(__raw_callee_save___pv_queued_spin_unlock, + PV_UNLOCK_ASM, .spinlock.text); =20 #else /* CONFIG_64BIT */ =20 diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 73be3931e4f0..ff9ad30a9484 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -385,6 +385,16 @@ apply_relocation(u8 *buf, size_t len, u8 *dest, u8 *sr= c, size_t src_len) } } =20 +/* Low-level backend functions usable from alternative code replacements. = */ +DEFINE_ASM_FUNC(nop_func, "", .entry.text); +EXPORT_SYMBOL_GPL(nop_func); + +noinstr void BUG_func(void) +{ + BUG(); +} +EXPORT_SYMBOL_GPL(BUG_func); + /* * Replace instructions with better alternatives for this CPU type. This r= uns * before SMP is initialized to avoid SMP problems with self modifying cod= e. diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index b8ab9ee5896c..4ca59dccc15a 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -803,8 +803,8 @@ extern bool __raw_callee_save___kvm_vcpu_is_preempted(l= ong); "cmpb $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax)\n\= t" \ "setne %al\n\t" =20 -DEFINE_PARAVIRT_ASM(__raw_callee_save___kvm_vcpu_is_preempted, - PV_VCPU_PREEMPTED_ASM, .text); +DEFINE_ASM_FUNC(__raw_callee_save___kvm_vcpu_is_preempted, + PV_VCPU_PREEMPTED_ASM, .text); #endif =20 static void __init kvm_guest_init(void) diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index 97f1436c1a20..acc5b1004f0f 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -34,14 +34,8 @@ #include #include =20 -/* - * nop stub, which must not clobber anything *including the stack* to - * avoid confusing the entry prologues. - */ -DEFINE_PARAVIRT_ASM(_paravirt_nop, "", .entry.text); - /* stub always returning 0. */ -DEFINE_PARAVIRT_ASM(paravirt_ret0, "xor %eax,%eax", .entry.text); +DEFINE_ASM_FUNC(paravirt_ret0, "xor %eax,%eax", .entry.text); =20 void __init default_banner(void) { @@ -49,12 +43,6 @@ void __init default_banner(void) pv_info.name); } =20 -/* Undefined instruction for dealing with missing ops pointers. */ -noinstr void paravirt_BUG(void) -{ - BUG(); -} - static unsigned paravirt_patch_call(void *insn_buff, const void *target, unsigned long addr, unsigned len) { @@ -64,11 +52,11 @@ static unsigned paravirt_patch_call(void *insn_buff, co= nst void *target, } =20 #ifdef CONFIG_PARAVIRT_XXL -DEFINE_PARAVIRT_ASM(_paravirt_ident_64, "mov %rdi, %rax", .text); -DEFINE_PARAVIRT_ASM(pv_native_save_fl, "pushf; pop %rax", .noinstr.text); -DEFINE_PARAVIRT_ASM(pv_native_irq_disable, "cli", .noinstr.text); -DEFINE_PARAVIRT_ASM(pv_native_irq_enable, "sti", .noinstr.text); -DEFINE_PARAVIRT_ASM(pv_native_read_cr2, "mov %cr2, %rax", .noinstr.text); +DEFINE_ASM_FUNC(_paravirt_ident_64, "mov %rdi, %rax", .text); +DEFINE_ASM_FUNC(pv_native_save_fl, "pushf; pop %rax", .noinstr.text); +DEFINE_ASM_FUNC(pv_native_irq_disable, "cli", .noinstr.text); +DEFINE_ASM_FUNC(pv_native_irq_enable, "sti", .noinstr.text); +DEFINE_ASM_FUNC(pv_native_read_cr2, "mov %cr2, %rax", .noinstr.text); #endif =20 DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key); @@ -96,9 +84,9 @@ unsigned int paravirt_patch(u8 type, void *insn_buff, uns= igned long addr, unsigned ret; =20 if (opfunc =3D=3D NULL) - /* If there's no function, patch it with paravirt_BUG() */ - ret =3D paravirt_patch_call(insn_buff, paravirt_BUG, addr, len); - else if (opfunc =3D=3D _paravirt_nop) + /* If there's no function, patch it with BUG_func() */ + ret =3D paravirt_patch_call(insn_buff, BUG_func, addr, len); + else if (opfunc =3D=3D nop_func) ret =3D 0; else /* Otherwise call the function. */ diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c index 6092fea7d651..39982f955cfe 100644 --- a/arch/x86/xen/irq.c +++ b/arch/x86/xen/irq.c @@ -45,7 +45,7 @@ static const typeof(pv_ops) xen_irq_ops __initconst =3D { /* Initial interrupt flag handling only called while interrupts off. */ .save_fl =3D __PV_IS_CALLEE_SAVE(paravirt_ret0), .irq_disable =3D __PV_IS_CALLEE_SAVE(paravirt_nop), - .irq_enable =3D __PV_IS_CALLEE_SAVE(paravirt_BUG), + .irq_enable =3D __PV_IS_CALLEE_SAVE(BUG_func), =20 .safe_halt =3D xen_safe_halt, .halt =3D xen_halt, --=20 2.35.3