Re: [PATCH 03/10] mini-os: don't assume contiguous RAM when initializing in PVH mode

From: Juergen Gross <jgross@suse.com>
To: Samuel Thibault <samuel.thibault@ens-lyon.org>,
	minios-devel@lists.xenproject.org,
	xen-devel@lists.xenproject.org, wl@xen.org
Subject: Re: [PATCH 03/10] mini-os: don't assume contiguous RAM when initializing in PVH mode
Date: Mon, 13 Dec 2021 15:58:58 +0100	[thread overview]
Message-ID: <e44571e4-ba85-06a4-99b2-648d94e9af8c@suse.com> (raw)
In-Reply-To: <20211212001542.qhz7wfdwq7k5ymxr@begin>

[-- Attachment #1.1.1: Type: text/plain, Size: 996 bytes --]

On 12.12.21 01:15, Samuel Thibault wrote:
> Juergen Gross, le lun. 06 déc. 2021 08:23:30 +0100, a ecrit:
>> -    unsigned long pfn, max = 0;
>> +    unsigned long pfns, max = 0;
> 
> I'd say rather rename max to start.
> 
>>       e820_get_memmap();
>>   
>> @@ -166,9 +166,12 @@ unsigned long e820_get_maxpfn(void)
>>       {
>>           if ( e820_map[i].type != E820_RAM )
>>               continue;
>> -        pfn = (e820_map[i].addr + e820_map[i].size) >> PAGE_SHIFT;
>> -        if ( pfn > max )
>> -            max = pfn;
>> +        pfns = e820_map[i].size >> PAGE_SHIFT;
>> +        max = e820_map[i].addr >> PAGE_SHIFT;
> 
> since it's it's always the start of the e820 entry.
> 
>> +        if ( pages <= pfns )
>> +            return max + pages;
>> +        pages -= pfns;
>> +        max += pfns;
> 
> Here we don't need do change max, only pages.

It is needed in case the loop is finished.

And this was the reason for naming it max.

Juergen

[-- Attachment #1.1.2: OpenPGP public key --]
[-- Type: application/pgp-keys, Size: 3135 bytes --]

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 495 bytes --]