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fix(VMPromising): Select TTBRs for ASID and root - #191

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fix/vmp-tcr-ttbr-selection
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fix(VMPromising): Select TTBRs for ASID and root#191
febyeji wants to merge 1 commit into
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fix/vmp-tcr-ttbr-selection

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@febyeji

@febyeji febyeji commented Jul 4, 2026 •
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@tperami

tperami commented Jul 4, 2026

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Simplified plan first:

  • Not reading TCR, assuming TTBR0 has the ASID
  • Ignoring the TCR entirely, assuming the expected configuration
  • For TLB lookup:
    • Get the ASID from TTBR0 independently of whether the VA in in the low or high range
  • For TLB fill:
    • If filling in the low range, do the same thing as before, read TTBR0 to get a linked ASID and page table root
    • If filling in the high range, need to both read TTBR0 and TTBR1 for the ASID and page table root.
      Then do the fill for all pairs of ASID+root in the Cartesian product.

@febyeji
febyeji force-pushed the fix/vmp-tcr-ttbr-selection branch 4 times, most recently from 320f7f8 to ebbb7db Compare July 4, 2026 14:57
@febyeji febyeji changed the title fix(VMPromising): Select TTBR from TCR ranges fix(VMPromising): Select TTBRs for ASID and root Jul 4, 2026
@febyeji
febyeji force-pushed the fix/vmp-tcr-ttbr-selection branch 5 times, most recently from d1ca646 to 63d0133 Compare July 4, 2026 15:35
@febyeji
febyeji requested a review from tperami July 4, 2026 15:38
tperami
tperami reviewed Jul 5, 2026
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Comment thread ArchSemArm/VMPromising.v Outdated
Comment thread ArchSemArm/VMPromising.v Outdated
Comment thread ArchSemArm/VMPromising.v Outdated
Comment thread ArchSemArm/VMPromising.v Outdated
@febyeji
febyeji force-pushed the fix/vmp-tcr-ttbr-selection branch from 63d0133 to 370ad1c Compare July 5, 2026 13:30
@febyeji
fix(VMPromising): Select TTBRs for ASID and root
2fb3ce1 
- Require TCR_EL1.A1 = 0 before selecting EL10 TTBRs.
- Use TTBR0_EL1 as the ASID source while selecting TTBR0_EL1 or TTBR1_EL1 as the page-table root from the VA range.
- Fill TLB entries over ASID/root candidates when the ASID source and root TTBR differ.

Related scenario:
- PR #191 high-range EL10 TLB fill uses TTBR0_EL1 as the ASID source and TTBR1_EL1 as the page-table root.

Related validation:
- No standalone litmus regression is checked into this branch; the focused validation target is ArchSemArm/VMPromising.vo.
@febyeji
febyeji force-pushed the fix/vmp-tcr-ttbr-selection branch from 370ad1c to 2fb3ce1 Compare July 5, 2026 21:20
febyeji added a commit that referenced this pull request Jul 7, 2026
@febyeji
fix(VMPromising): Select TTBRs for ASID and root
a0f0b32 
- Require TCR_EL1.A1 = 0 before selecting EL10 TTBRs.
- Use TTBR0_EL1 as the ASID source while selecting TTBR0_EL1 or TTBR1_EL1 as the page-table root from the VA range.
- Fill TLB entries over ASID/root candidates when the ASID source and root TTBR differ.

Related scenario:
- PR #191 high-range EL10 TLB fill uses TTBR0_EL1 as the ASID source and TTBR1_EL1 as the page-table root.

Related validation:
- No standalone litmus regression is checked into this branch; the focused validation target is ArchSemArm/VMPromising.vo.
febyeji added a commit that referenced this pull request Jul 7, 2026
@febyeji
fix(VMPromising): Select TTBRs for ASID and root
f286dab 
- Require TCR_EL1.A1 = 0 before selecting EL10 TTBRs.
- Use TTBR0_EL1 as the ASID source while selecting TTBR0_EL1 or TTBR1_EL1 as the page-table root from the VA range.
- Fill TLB entries over ASID/root candidates when the ASID source and root TTBR differ.

Related scenario:
- PR #191 high-range EL10 TLB fill uses TTBR0_EL1 as the ASID source and TTBR1_EL1 as the page-table root.

Related validation:
- No standalone litmus regression is checked into this branch; the focused validation target is ArchSemArm/VMPromising.vo.
febyeji added a commit that referenced this pull request Jul 7, 2026
@febyeji
fix(VMPromising): Select TTBRs for ASID and root
9a10c7b 
- Require TCR_EL1.A1 = 0 before selecting EL10 TTBRs.
- Use TTBR0_EL1 as the ASID source while selecting TTBR0_EL1 or TTBR1_EL1 as the page-table root from the VA range.
- Fill TLB entries over ASID/root candidates when the ASID source and root TTBR differ.

Related scenario:
- PR #191 high-range EL10 TLB fill uses TTBR0_EL1 as the ASID source and TTBR1_EL1 as the page-table root.

Related validation:
- No standalone litmus regression is checked into this branch; the focused validation target is ArchSemArm/VMPromising.vo.
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VMPromising: Use TCR_EL1 to select ASID

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@febyeji @tperami