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 4D617C636D3 for ; Tue, 7 Feb 2023 21:09:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229830AbjBGVJ6 (ORCPT ); Tue, 7 Feb 2023 16:09:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230075AbjBGVJu (ORCPT ); Tue, 7 Feb 2023 16:09:50 -0500 Received: from outgoing2021.csail.mit.edu (outgoing2021.csail.mit.edu [128.30.2.78]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 417D137555 for ; Tue, 7 Feb 2023 13:09:49 -0800 (PST) Received: from vmware-inc.ear2.seattle1.level3.net ([4.30.137.154] helo=srivatsab3MD6R.vmware.com) by outgoing2021.csail.mit.edu with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.95) (envelope-from ) id 1pPVDJ-005MHi-J6; Tue, 07 Feb 2023 16:09:17 -0500 Subject: Re: [PATCH v2] x86/paravirt: merge activate_mm and dup_mmap callbacks To: Juergen Gross , linux-kernel@vger.kernel.org, x86@kernel.org, virtualization@lists.linux-foundation.org Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Alexey Makhalov , VMware PV-Drivers Reviewers , Andy Lutomirski , Peter Zijlstra , Boris Ostrovsky , xen-devel@lists.xenproject.org References: <20230207075902.7539-1-jgross@suse.com> From: "Srivatsa S. Bhat" Message-ID: Date: Tue, 7 Feb 2023 13:09:15 -0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <20230207075902.7539-1-jgross@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/6/23 11:59 PM, Juergen Gross wrote: > The two paravirt callbacks .mmu.activate_mm and .mmu.dup_mmap are > sharing the same implementations in all cases: for Xen PV guests they > are pinning the PGD of the new mm_struct, and for all other cases > they are a NOP. > > In the end both callbacks are meant to register an address space with > the underlying hypervisor, so there needs to be only a single callback > for that purpose. > > So merge them to a common callback .mmu.enter_mmap (in contrast to the > corresponding already existing .mmu.exit_mmap). > > As the first parameter of the old callbacks isn't used, drop it from > the replacement one. > > Signed-off-by: Juergen Gross > Reviewed-by: Boris Ostrovsky Reviewed-by: Srivatsa S. Bhat (VMware) Regards, Srivatsa VMware Photon OS > --- > V2: > - expand commit message (Srivatsa S. Bhat) > --- > arch/x86/include/asm/mmu_context.h | 4 ++-- > arch/x86/include/asm/paravirt.h | 14 +++----------- > arch/x86/include/asm/paravirt_types.h | 7 ++----- > arch/x86/kernel/paravirt.c | 3 +-- > arch/x86/mm/init.c | 2 +- > arch/x86/xen/mmu_pv.c | 12 ++---------- > 6 files changed, 11 insertions(+), 31 deletions(-) > > diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h > index b8d40ddeab00..6a14b6c2165c 100644 > --- a/arch/x86/include/asm/mmu_context.h > +++ b/arch/x86/include/asm/mmu_context.h > @@ -134,7 +134,7 @@ extern void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, > > #define activate_mm(prev, next) \ > do { \ > - paravirt_activate_mm((prev), (next)); \ > + paravirt_enter_mmap(next); \ > switch_mm((prev), (next), NULL); \ > } while (0); > > @@ -167,7 +167,7 @@ static inline void arch_dup_pkeys(struct mm_struct *oldmm, > static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) > { > arch_dup_pkeys(oldmm, mm); > - paravirt_arch_dup_mmap(oldmm, mm); > + paravirt_enter_mmap(mm); > return ldt_dup_context(oldmm, mm); > } > > diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h > index 73e9522db7c1..07bbdceaf35a 100644 > --- a/arch/x86/include/asm/paravirt.h > +++ b/arch/x86/include/asm/paravirt.h > @@ -332,16 +332,9 @@ static inline void tss_update_io_bitmap(void) > } > #endif > > -static inline void paravirt_activate_mm(struct mm_struct *prev, > - struct mm_struct *next) > +static inline void paravirt_enter_mmap(struct mm_struct *next) > { > - PVOP_VCALL2(mmu.activate_mm, prev, next); > -} > - > -static inline void paravirt_arch_dup_mmap(struct mm_struct *oldmm, > - struct mm_struct *mm) > -{ > - PVOP_VCALL2(mmu.dup_mmap, oldmm, mm); > + PVOP_VCALL1(mmu.enter_mmap, next); > } > > static inline int paravirt_pgd_alloc(struct mm_struct *mm) > @@ -787,8 +780,7 @@ extern void default_banner(void); > > #ifndef __ASSEMBLY__ > #ifndef CONFIG_PARAVIRT_XXL > -static inline void paravirt_arch_dup_mmap(struct mm_struct *oldmm, > - struct mm_struct *mm) > +static inline void paravirt_enter_mmap(struct mm_struct *mm) > { > } > #endif > diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h > index 8c1da419260f..71bf64b963df 100644 > --- a/arch/x86/include/asm/paravirt_types.h > +++ b/arch/x86/include/asm/paravirt_types.h > @@ -164,11 +164,8 @@ struct pv_mmu_ops { > unsigned long (*read_cr3)(void); > void (*write_cr3)(unsigned long); > > - /* Hooks for intercepting the creation/use of an mm_struct. */ > - void (*activate_mm)(struct mm_struct *prev, > - struct mm_struct *next); > - void (*dup_mmap)(struct mm_struct *oldmm, > - struct mm_struct *mm); > + /* Hook for intercepting the creation/use of an mm_struct. */ > + void (*enter_mmap)(struct mm_struct *mm); > > /* Hooks for allocating and freeing a pagetable top-level */ > int (*pgd_alloc)(struct mm_struct *mm); > diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c > index 327757afb027..ff1109b9c6cd 100644 > --- a/arch/x86/kernel/paravirt.c > +++ b/arch/x86/kernel/paravirt.c > @@ -352,8 +352,7 @@ struct paravirt_patch_template pv_ops = { > .mmu.make_pte = PTE_IDENT, > .mmu.make_pgd = PTE_IDENT, > > - .mmu.dup_mmap = paravirt_nop, > - .mmu.activate_mm = paravirt_nop, > + .mmu.enter_mmap = paravirt_nop, > > .mmu.lazy_mode = { > .enter = paravirt_nop, > diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c > index cb258f58fdc8..cbc53da4c1b4 100644 > --- a/arch/x86/mm/init.c > +++ b/arch/x86/mm/init.c > @@ -806,7 +806,7 @@ void __init poking_init(void) > BUG_ON(!poking_mm); > > /* Xen PV guests need the PGD to be pinned. */ > - paravirt_arch_dup_mmap(NULL, poking_mm); > + paravirt_enter_mmap(poking_mm); > > /* > * Randomize the poking address, but make sure that the following page > diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c > index ee29fb558f2e..b3b8d289b9ab 100644 > --- a/arch/x86/xen/mmu_pv.c > +++ b/arch/x86/xen/mmu_pv.c > @@ -885,14 +885,7 @@ void xen_mm_unpin_all(void) > spin_unlock(&pgd_lock); > } > > -static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next) > -{ > - spin_lock(&next->page_table_lock); > - xen_pgd_pin(next); > - spin_unlock(&next->page_table_lock); > -} > - > -static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) > +static void xen_enter_mmap(struct mm_struct *mm) > { > spin_lock(&mm->page_table_lock); > xen_pgd_pin(mm); > @@ -2153,8 +2146,7 @@ static const typeof(pv_ops) xen_mmu_ops __initconst = { > .make_p4d = PV_CALLEE_SAVE(xen_make_p4d), > #endif > > - .activate_mm = xen_activate_mm, > - .dup_mmap = xen_dup_mmap, > + .enter_mmap = xen_enter_mmap, > .exit_mmap = xen_exit_mmap, > > .lazy_mode = { >