Hello every body. I need help. I use Intel(R) Core(TM)2 Duo CPU P8600 @ 2.40GHz with BIOS v2 mother board. When I start PC (Laptop), BIOS is OK, then my personal loaders loads 40 sectors in memory starting at 0x7000 and I switch to protected mode and my personal software starts and runs correctly. There is only 3 GiB of memory installed and when I read ABAR (5) of the PCI SATA device, the answer is 0xFFCFF000. This Base Address is outside of the memory so of cause I can not use this PCI SATA Device. If I switch to long mode and give 1Gib available for the last GiByte (Top) I can write to 0xFFCFF000 +( Reg num) but nothings appends.
Q: Why BIOS provides ABAR5 outside of memory installed on its mother board.
Strange value in PCI ABAR
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Octocontrabass
- Member
- Posts: 5563
- Joined: Mon Mar 25, 2013 7:01 pm
Re: Strange value in PCI ABAR
MMIO is not memory. The ABAR contains the physical address of AHCI MMIO.
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Daniel06700
- Posts: 2
- Joined: Sat Jun 11, 2022 8:59 am
Re: Strange value in PCI ABAR
Thank you Octocontrabass. Yes of course ! I had forgot this 
I had modify my PML4E to access to that physical address and now all it is OK. Thank's a lot again. Best regards
I had modify my PML4E to access to that physical address and now all it is OK. Thank's a lot again. Best regards