linux-kernel - Re: [PATCH] xen,kdump: handle pv domain in paddr_vmcoreinfo

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Message-ID: <1de1fa53-faa4-3d6d-2bf9-f786dbaebd3d@suse.com>
Date:   Fri, 31 Mar 2017 10:03:20 +0200
From:   Juergen Gross <jgross@...e.com>
To:     Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org
Cc:     ptesarik@...e.com
Subject: Re: [PATCH] xen,kdump: handle pv domain in paddr_vmcoreinfo_note()

On 30/03/17 16:51, Boris Ostrovsky wrote:
> On 03/30/2017 10:18 AM, Juergen Gross wrote:
>> For kdump to work correctly it needs the physical address of
>> vmcoreinfo_note. When running as dom0 this means the virtual address
>> has to be translated to the related machine address.
>>
>> paddr_vmcoreinfo_note() is meant to do the translation via __pa() only,
>> but being attributed "weak" it can be replaced easily in Xen case.
>>
>> Signed-off-by: Juergen Gross <jgross@...e.com>
>> ---
>> This patch needs to be rebased on top of Vitaly's series to split
>> pv- and hvm-code. I'll do this as soon as his series is in the Xen
>> tree in its final form.
>> ---
>>  arch/x86/xen/mmu.c | 13 +++++++++++++
>>  1 file changed, 13 insertions(+)
>>
>> diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
>> index 37cb5aa..0e2b8d7 100644
>> --- a/arch/x86/xen/mmu.c
>> +++ b/arch/x86/xen/mmu.c
>> @@ -49,6 +49,9 @@
>>  #include <linux/memblock.h>
>>  #include <linux/seq_file.h>
>>  #include <linux/crash_dump.h>
>> +#ifdef CONFIG_KEXEC_CORE
>> +#include <linux/kexec.h>
>> +#endif
>>  
>>  #include <trace/events/xen.h>
>>  
>> @@ -2903,3 +2906,13 @@ int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
>>  	return -EINVAL;
>>  }
>>  EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range);
>> +
>> +#ifdef CONFIG_KEXEC_CORE
>> +phys_addr_t paddr_vmcoreinfo_note(void)
>> +{
>> +	if (xen_pv_domain())
>> +		return virt_to_machine(&vmcoreinfo_note).maddr;
>> +	else
>> +		return __pa((unsigned long)(char *)&vmcoreinfo_note);
> 
> Why not __pa_symbol(), just like in the weak version?

Hmm, you are right. This patch originated from a 4.4 based one.


Juergen