Fixes in VM Entry Checks for Guest Segment Registers #51
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
stlintel
pushed a commit
that referenced
this pull request
Aug 20, 2023
Fixes in VM Entry Checks for Guest Segment Registers #51 Correction in Type range checks for DS, ES, FS, GS: The original code erroneously applied the check for types less than 11, excluding types equal to 11. This is not in accordance with Intel SDM, Vol. 3C, Chapter 27.3.1.2, which states that the check should include types equal to or less than 11. This fix corrects this by including types equal to or less than 11 in the check.
stlintel
force-pushed
the
bugfix/vmcs-check
branch
from
5227b0b to
f95cda2
Compare
|
part 2 merged to main, verifying part 1 |
stlintel
pushed a commit
that referenced
this pull request
Aug 20, 2023
from Fixes in VM Entry Checks for Guest Segment Registers #51 Correction in checks for Code Segment (CS): Previously, the DPL of CS was incorrectly compared with its own RPL. According to Intel SDM, Vol. 3C, Chapter 27.3.1.2, for non-conforming code segments (type 9 or 11), the DPL of CS should be equal to the DPL of SS. And for conforming code segments (type 13 or 15), the DPL of CS cannot be greater than the DPL of SS. This way VMCS is not accessed multiple times which is important for some usages
|
Merged into main with slightly different implementation. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This pull request includes two critical fixes in the VM entry checks related to the segment registers, ensuring better conformity with the Intel Software Developer's Manual.
Correction in checks for Code Segment (CS):
Previously, the DPL of CS was incorrectly compared with its own RPL.
According to Intel SDM, Vol. 3C, Chapter 27.3.1.2, for non-conforming code segments (type 9 or 11), the DPL of CS should be equal to the DPL of SS.
And for conforming code segments (type 13 or 15), the DPL of CS cannot be greater than the DPL of SS.
Correction in Type range checks for DS, ES, FS, GS:
The original code erroneously applied the check for types less than 11, excluding types equal to 11.
This is not in accordance with Intel SDM, Vol. 3C, Chapter 27.3.1.2, which states that the check should include types equal to or less than 11.
This fix corrects this by including types equal to or less than 11 in the check.