LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Janosch Frank <frankja@linux.ibm.com>
To: David Hildenbrand <david@redhat.com>,
	Janis Schoetterl-Glausch <scgl@linux.ibm.com>,
	kvm@vger.kernel.org, borntraeger@de.ibm.com,
	imbrenda@linux.ibm.com, Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>
Cc: cohuck@redhat.com, linux-s390@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] KVM: s390: gaccess: Cleanup access to guest frames
Date: Wed, 18 Aug 2021 10:06:31 +0200	[thread overview]
Message-ID: <584ca757-4eb4-491e-a4cd-7bc60fb04b61@linux.ibm.com> (raw)
In-Reply-To: <d11128bb-18f6-5210-6f42-74a89d8edcf7@redhat.com>

On 8/18/21 9:54 AM, David Hildenbrand wrote:
> On 16.08.21 17:07, Janis Schoetterl-Glausch wrote:
>> Introduce a helper function for guest frame access.
>> Rewrite the calculation of the gpa and the length of the segment
>> to be more readable.
>>
>> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
[...]
>> -	unsigned long _len, gpa;
>> +	unsigned long gpa;
>> +	unsigned int seg;
>>   	int rc = 0;
>>   
>>   	while (len && !rc) {
>>   		gpa = kvm_s390_real_to_abs(vcpu, gra);
>> -		_len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len);
>> -		if (mode)
>> -			rc = write_guest_abs(vcpu, gpa, data, _len);
>> -		else
>> -			rc = read_guest_abs(vcpu, gpa, data, _len);
>> -		len -= _len;
>> -		gra += _len;
>> -		data += _len;
>> +		seg = min(PAGE_SIZE - offset_in_page(gpa), len);
> 
> What does "seg" mean? I certainly know when "len" means -- which is also 
> what the function eats.

What does "_len" mean especially in contrast to "len"?

"seg" is used in the common kvm guest access functions so it's at least
consistent although I share the sentiment that it's not a great name for
the length we access inside the page.

Originally I suggested "len_in_page" if you have a better name I'd
expect we'll both be happy to discuss it :-)

> 
>> +		rc = access_guest_frame(vcpu->kvm, mode, gpa, data, seg);
>> +		len -= seg;
>> +		gra += seg;
>> +		data += seg;
>>   	}
>>   	return rc;
>>   }
>>
> 
> 


  reply	other threads:[~2021-08-18  8:06 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20210816150718.3063877-1-scgl@linux.ibm.com>
2021-08-16 15:07 ` Janis Schoetterl-Glausch
2021-08-18  7:46   ` Janosch Frank
2021-08-18  7:54   ` David Hildenbrand
2021-08-18  8:06     ` Janosch Frank [this message]
2021-08-18  8:44       ` David Hildenbrand
2021-08-18  8:48         ` Janis Schoetterl-Glausch
2021-08-19 13:53       ` Janis Schoetterl-Glausch
2021-08-19 14:11         ` Janosch Frank
2021-08-18  9:00     ` Janis Schoetterl-Glausch
2021-08-16 15:07 ` [PATCH 2/2] KVM: s390: gaccess: Refactor access address range check Janis Schoetterl-Glausch
2021-08-18 10:08   ` Claudio Imbrenda
2021-08-19 12:39     ` Janis Schoetterl-Glausch

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=584ca757-4eb4-491e-a4cd-7bc60fb04b61@linux.ibm.com \
    --to=frankja@linux.ibm.com \
    --cc=borntraeger@de.ibm.com \
    --cc=cohuck@redhat.com \
    --cc=david@redhat.com \
    --cc=gor@linux.ibm.com \
    --cc=hca@linux.ibm.com \
    --cc=imbrenda@linux.ibm.com \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-s390@vger.kernel.org \
    --cc=scgl@linux.ibm.com \
    --subject='Re: [PATCH 1/2] KVM: s390: gaccess: Cleanup access to guest frames' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).