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| author | Sean Christopherson <[email protected]> | 2019-08-23 20:55:44 +0000 |
|---|---|---|
| committer | Radim Krčmář <[email protected]> | 2019-08-27 18:59:04 +0000 |
| commit | 75ee23b30dc712d80d2421a9a547e7ab6e379b44 (patch) | |
| tree | eb8a7a231a1ab4e740507fe6751ca5ac99148b99 /tools/perf/scripts/python/compaction-times.py | |
| parent | KVM: x86: hyper-v: don't crash on KVM_GET_SUPPORTED_HV_CPUID when kvm_intel.n... (diff) | |
| download | kernel-75ee23b30dc712d80d2421a9a547e7ab6e379b44.tar.gz kernel-75ee23b30dc712d80d2421a9a547e7ab6e379b44.zip | |
KVM: x86: Don't update RIP or do single-step on faulting emulation
Don't advance RIP or inject a single-step #DB if emulation signals a
fault. This logic applies to all state updates that are conditional on
clean retirement of the emulation instruction, e.g. updating RFLAGS was
previously handled by commit 38827dbd3fb85 ("KVM: x86: Do not update
EFLAGS on faulting emulation").
Not advancing RIP is likely a nop, i.e. ctxt->eip isn't updated with
ctxt->_eip until emulation "retires" anyways. Skipping #DB injection
fixes a bug reported by Andy Lutomirski where a #UD on SYSCALL due to
invalid state with EFLAGS.TF=1 would loop indefinitely due to emulation
overwriting the #UD with #DB and thus restarting the bad SYSCALL over
and over.
Cc: Nadav Amit <[email protected]>
Cc: [email protected]
Reported-by: Andy Lutomirski <[email protected]>
Fixes: 663f4c61b803 ("KVM: x86: handle singlestep during emulation")
Signed-off-by: Sean Christopherson <[email protected]>
Signed-off-by: Radim Krčmář <[email protected]>
Diffstat (limited to 'tools/perf/scripts/python/compaction-times.py')
0 files changed, 0 insertions, 0 deletions