* [Bug 1909823] [NEW] RDPMC check on PCE is backwards
@ 2021-01-01 17:50 Bruce Merry
2021-05-12 11:27 ` [Bug 1909823] " Thomas Huth
2021-05-15 8:32 ` Bruce Merry
0 siblings, 2 replies; 3+ messages in thread
From: Bruce Merry @ 2021-01-01 17:50 UTC (permalink / raw)
To: qemu-devel
Public bug reported:
At [this
line](https://github.com/qemu/qemu/blob/75ee62ac606bfc9eb59310b9446df3434bf6e8c2/target/i386/tcg/misc_helper.c#L225)
the check on CR4_PCE_MASK is backwards: it's raising an exception if the
flag is set (and CPL != 0) rather than if the flag is clear.
It's low priority at the moment because the instruction isn't
implemented, so you get an illegal opcode exception when expecting a
GPF, or vice versa, but it's a time bomb for if it is ever implemented.
The Intel docs also indicate that CR0.PE influences the protection; I
don't know if that's already reflected in env->hflags & HF_CPL_MASK.
** Affects: qemu
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/1909823
Title:
RDPMC check on PCE is backwards
Status in QEMU:
New
Bug description:
At [this
line](https://github.com/qemu/qemu/blob/75ee62ac606bfc9eb59310b9446df3434bf6e8c2/target/i386/tcg/misc_helper.c#L225)
the check on CR4_PCE_MASK is backwards: it's raising an exception if
the flag is set (and CPL != 0) rather than if the flag is clear.
It's low priority at the moment because the instruction isn't
implemented, so you get an illegal opcode exception when expecting a
GPF, or vice versa, but it's a time bomb for if it is ever
implemented.
The Intel docs also indicate that CR0.PE influences the protection; I
don't know if that's already reflected in env->hflags & HF_CPL_MASK.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1909823/+subscriptions
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug 1909823] Re: RDPMC check on PCE is backwards
2021-01-01 17:50 [Bug 1909823] [NEW] RDPMC check on PCE is backwards Bruce Merry
@ 2021-05-12 11:27 ` Thomas Huth
2021-05-15 8:32 ` Bruce Merry
1 sibling, 0 replies; 3+ messages in thread
From: Thomas Huth @ 2021-05-12 11:27 UTC (permalink / raw)
To: qemu-devel
The QEMU project is currently moving its bug tracking to another system.
For this we need to know which bugs are still valid and which could be
closed already. Thus we are setting the bug state to "Incomplete" now.
If the bug has already been fixed in the latest upstream version of QEMU,
then please close this ticket as "Fix released".
If it is not fixed yet and you think that this bug report here is still
valid, then you have two options:
1) If you already have an account on gitlab.com, please open a new ticket
for this problem in our new tracker here:
https://gitlab.com/qemu-project/qemu/-/issues
and then close this ticket here on Launchpad (or let it expire auto-
matically after 60 days). Please mention the URL of this bug ticket on
Launchpad in the new ticket on GitLab.
2) If you don't have an account on gitlab.com and don't intend to get
one, but still would like to keep this ticket opened, then please switch
the state back to "New" or "Confirmed" within the next 60 days (other-
wise it will get closed as "Expired"). We will then eventually migrate
the ticket automatically to the new system (but you won't be the reporter
of the bug in the new system and thus you won't get notified on changes
anymore).
Thank you and sorry for the inconvenience.
** Tags added: i386 tcg
** Changed in: qemu
Status: New => Incomplete
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You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/1909823
Title:
RDPMC check on PCE is backwards
Status in QEMU:
Incomplete
Bug description:
At [this
line](https://github.com/qemu/qemu/blob/75ee62ac606bfc9eb59310b9446df3434bf6e8c2/target/i386/tcg/misc_helper.c#L225)
the check on CR4_PCE_MASK is backwards: it's raising an exception if
the flag is set (and CPL != 0) rather than if the flag is clear.
It's low priority at the moment because the instruction isn't
implemented, so you get an illegal opcode exception when expecting a
GPF, or vice versa, but it's a time bomb for if it is ever
implemented.
The Intel docs also indicate that CR0.PE influences the protection; I
don't know if that's already reflected in env->hflags & HF_CPL_MASK.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1909823/+subscriptions
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug 1909823] Re: RDPMC check on PCE is backwards
2021-01-01 17:50 [Bug 1909823] [NEW] RDPMC check on PCE is backwards Bruce Merry
2021-05-12 11:27 ` [Bug 1909823] " Thomas Huth
@ 2021-05-15 8:32 ` Bruce Merry
1 sibling, 0 replies; 3+ messages in thread
From: Bruce Merry @ 2021-05-15 8:32 UTC (permalink / raw)
To: qemu-devel
It looks like this was fixed in c45b426.
** Changed in: qemu
Status: Incomplete => Fix Released
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You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/1909823
Title:
RDPMC check on PCE is backwards
Status in QEMU:
Fix Released
Bug description:
At [this
line](https://github.com/qemu/qemu/blob/75ee62ac606bfc9eb59310b9446df3434bf6e8c2/target/i386/tcg/misc_helper.c#L225)
the check on CR4_PCE_MASK is backwards: it's raising an exception if
the flag is set (and CPL != 0) rather than if the flag is clear.
It's low priority at the moment because the instruction isn't
implemented, so you get an illegal opcode exception when expecting a
GPF, or vice versa, but it's a time bomb for if it is ever
implemented.
The Intel docs also indicate that CR0.PE influences the protection; I
don't know if that's already reflected in env->hflags & HF_CPL_MASK.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1909823/+subscriptions
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-05-15 8:43 UTC | newest]
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2021-01-01 17:50 [Bug 1909823] [NEW] RDPMC check on PCE is backwards Bruce Merry
2021-05-12 11:27 ` [Bug 1909823] " Thomas Huth
2021-05-15 8:32 ` Bruce Merry
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