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From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Juergen Gross <jgross@suse.com>,
	xen-devel@lists.xenproject.org, x86@kernel.org,
	linux-kernel@vger.kernel.org
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Andy Lutomirski <luto@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v2 1/4] x86/xen: remove 32-bit Xen PV guest support
Date: Thu, 2 Jul 2020 18:59:21 -0400
Message-ID: <6d0b517a-6c53-61d3-117b-40e33e013037@oracle.com> (raw)
In-Reply-To: <20200701110650.16172-2-jgross@suse.com>

On 7/1/20 7:06 AM, Juergen Gross wrote:
> Xen is requiring 64-bit machines today and since Xen 4.14 it can be
> built without 32-bit PV guest support. There is no need to carry the
> burden of 32-bit PV guest support in the kernel any longer, as new
> guests can be either HVM or PVH, or they can use a 64 bit kernel.
>
> Remove the 32-bit Xen PV support from the kernel.
>
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
>  arch/x86/entry/entry_32.S      | 109 +----------
>  arch/x86/include/asm/proto.h   |   2 +-
>  arch/x86/include/asm/segment.h |   2 +-
>  arch/x86/kernel/head_32.S      |  31 ---
>  arch/x86/xen/Kconfig           |   3 +-
>  arch/x86/xen/Makefile          |   3 +-
>  arch/x86/xen/apic.c            |  17 --
>  arch/x86/xen/enlighten_pv.c    |  48 +----


Should we drop PageHighMem() test in set_aliased_prot()?


(And there are few other places where is is used, in mmu_pv.c)



> @@ -555,13 +547,8 @@ static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
>  	 * exception between the new %fs descriptor being loaded and
>  	 * %fs being effectively cleared at __switch_to().
>  	 */
> -	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
> -#ifdef CONFIG_X86_32
> -		lazy_load_gs(0);
> -#else


I think this also needs an adjustment to the preceding comment.


>  
> -#ifdef CONFIG_X86_PAE
> -static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
> -{
> -	trace_xen_mmu_set_pte_atomic(ptep, pte);
> -	__xen_set_pte(ptep, pte);


Probably not for this series but I wonder whether __xen_set_pte() should
continue to use hypercall now that we are 64-bit only.


> @@ -654,14 +621,12 @@ static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,


Comment above should be updated.


-boris



  parent reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-01 11:06 [PATCH v2 0/4] Remove " Juergen Gross
2020-07-01 11:06 ` [PATCH v2 1/4] x86/xen: remove " Juergen Gross
2020-07-01 16:33   ` Brian Gerst
2020-07-02 22:59   ` Boris Ostrovsky [this message]
2020-07-02 23:24     ` Andrew Cooper
2020-07-02 23:27       ` Boris Ostrovsky
2020-07-03  5:15     ` Jürgen Groß
2020-07-01 11:06 ` [PATCH v2 2/4] x86/paravirt: remove 32-bit support from PARAVIRT_XXL Juergen Gross
2020-07-01 11:06 ` [PATCH v2 3/4] x86/paravirt: cleanup paravirt macros Juergen Gross
2020-07-01 11:06 ` [PATCH v2 4/4] x86/paravirt: use CONFIG_PARAVIRT_XXL instead of CONFIG_PARAVIRT Juergen Gross
2020-07-02  8:18 ` [PATCH v2 0/4] Remove 32-bit Xen PV guest support Peter Zijlstra
2020-07-02 14:48 ` Brian Gerst
2020-07-02 15:45   ` Jürgen Groß

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