linux-kernel - Re: [PATCH 1/2] x86/xen: remove 32-bit Xen PV guest support

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Date:   Tue, 16 Jul 2019 05:52:22 +0200
From:   Juergen Gross <jgross@...e.com>
To:     Boris Ostrovsky <boris.ostrovsky@...cle.com>, x86@...nel.org,
        xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org
Cc:     Borislav Petkov <bp@...en8.de>, Andy Lutomirski <luto@...nel.org>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH 1/2] x86/xen: remove 32-bit Xen PV guest support

On 15.07.19 17:44, Boris Ostrovsky wrote:
> 
>> diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
>> index 084de77a109e..d42737f31304 100644
>> --- a/arch/x86/xen/Makefile
>> +++ b/arch/x86/xen/Makefile
>> @@ -1,5 +1,5 @@
>>   # SPDX-License-Identifier: GPL-2.0
>> -OBJECT_FILES_NON_STANDARD_xen-asm_$(BITS).o := y
>> +OBJECT_FILES_NON_STANDARD_xen-asm_64.o := y
>>   
>>   ifdef CONFIG_FUNCTION_TRACER
>>   # Do not profile debug and lowlevel utilities
>> @@ -34,7 +34,7 @@ obj-$(CONFIG_XEN_PV)		+= mmu_pv.o
>>   obj-$(CONFIG_XEN_PV)		+= irq.o
>>   obj-$(CONFIG_XEN_PV)		+= multicalls.o
>>   obj-$(CONFIG_XEN_PV)		+= xen-asm.o
>> -obj-$(CONFIG_XEN_PV)		+= xen-asm_$(BITS).o
>> +obj-$(CONFIG_XEN_PV)		+= xen-asm_64.o
> 
> We should be able to merge xen-asm_64.S into xen-asm.S, shouldn't we?

Yes, probably a good idea to add that.

>> @@ -1312,15 +1290,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
>>   
>>   	/* keep using Xen gdt for now; no urgent need to change it */
>>   
>> -#ifdef CONFIG_X86_32
>> -	pv_info.kernel_rpl = 1;
>> -	if (xen_feature(XENFEAT_supervisor_mode_kernel))
>> -		pv_info.kernel_rpl = 0;
>> -#else
>>   	pv_info.kernel_rpl = 0;
> 
> Is kernel_rpl needed anymore?

Yes, this can be dropped, together with get_kernel_rpl().


Juergen