Cheat Engine Forum Index Cheat Engine
The Official Site of Cheat Engine
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 


Memory With WriteCombine Protection

 
Post new topic   Reply to topic    Cheat Engine Forum Index -> General Discussions
View previous topic :: View next topic  
Author Message
lylcheat
Cheater
Reputation: 0

Joined: 14 Feb 2009
Posts: 27
Location: Planet 3 Solar System Orion Arm Spiral Galaxy Milky Way

PostPosted: Thu May 23, 2019 3:36 am    Post subject: Memory With WriteCombine Protection Reply with quote

I'm using systinternal's VMMap to list the memory map of a game client.
I notice that some memory regions have the protection attribute WriteCombine.
The msdn page https://docs.microsoft.com/en-us/windows/desktop/Memory/memory-protection-constants has some vague description and i guess that these writecombine pages should be some kind of shared video memory since I am using on-board display chip to play my game.

My question
1) what exactly are these pages with Writecombine protection flag?
2) how do we skip all these Writecombine pages when scanning, just like skipping non-writable pages[/url]



writecombine.png
 Description:
 Filesize:  103.68 KB
 Viewed:  625 Time(s)

writecombine.png


Back to top
View user's profile Send private message
Dark Byte
Site Admin
Reputation: 368

Joined: 09 May 2003
Posts: 21784
Location: The netherlands

PostPosted: Thu May 23, 2019 4:17 am    Post subject: Reply with quote

write combine is a paging technique where some caching happens but writes get sent to the hardware immediately

Normally those memoryregions are marked as mem_mapped, and by default CE will skip that

check with memoryview-view-memory regions

_________________
Do not ask me about online cheats. I don't know any and wont help finding them.

Like my help? Join me on Patreon so i can keep helping
Back to top
View user's profile Send private message MSN Messenger
lylcheat
Cheater
Reputation: 0

Joined: 14 Feb 2009
Posts: 27
Location: Planet 3 Solar System Orion Arm Spiral Galaxy Milky Way

PostPosted: Thu May 23, 2019 4:49 am    Post subject: Reply with quote

Dark Byte wrote:
write combine is a paging technique where some caching happens but writes get sent to the hardware immediately

Normally those memoryregions are marked as mem_mapped, and by default CE will skip that

check with memoryview-view-memory regions


Look at my printscreen, clearly both private memory MEM_PRIVATE (those in yellow) and sharable MEM_MAPPED (those in white, i.e. mem_mapped memory which are backed by paging file) can be Writecombine (it is a memory protection attribute not memory type). So skipping MEM_MAPPED seems not specific enough.
Back to top
View user's profile Send private message
Dark Byte
Site Admin
Reputation: 368

Joined: 09 May 2003
Posts: 21784
Location: The netherlands

PostPosted: Thu May 23, 2019 4:56 am    Post subject: Reply with quote

post a screenshot of CE's memory regions window
_________________
Do not ask me about online cheats. I don't know any and wont help finding them.

Like my help? Join me on Patreon so i can keep helping
Back to top
View user's profile Send private message MSN Messenger
lylcheat
Cheater
Reputation: 0

Joined: 14 Feb 2009
Posts: 27
Location: Planet 3 Solar System Orion Arm Spiral Galaxy Milky Way

PostPosted: Fri May 24, 2019 3:18 am    Post subject: Reply with quote

Here is a screen shot using mame64 as the client (without anti-cheat issue).
CE doesn't seem to support WriteCombine flag at all. 0x16891000 is the mem page with WriteCombine flag as seen in VMMap, but it it not shown by CE. When scanning this memory page is treated as ordinary committed private page.



ce_mame.png
 Description:
cheat engine memory region print screen
 Filesize:  50.54 KB
 Viewed:  584 Time(s)

ce_mame.png



vmmap_mame.png
 Description:
sysinternals' vmmap
 Filesize:  110.96 KB
 Viewed:  584 Time(s)

vmmap_mame.png


Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Cheat Engine Forum Index -> General Discussions All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Powered by phpBB © 2001, 2005 phpBB Group

CE Wiki   IRC (#CEF)   Twitter
Third party websites