From: bugzilla-daemon@bugzilla.kernel.org
To: kvm@vger.kernel.org
Subject: [Bug 213257] New: KVM-PR: FPU is broken when single-stepping
Date: Fri, 28 May 2021 11:20:22 +0000 [thread overview]
Message-ID: <bug-213257-28872@https.bugzilla.kernel.org/> (raw)
https://bugzilla.kernel.org/show_bug.cgi?id=213257
Bug ID: 213257
Summary: KVM-PR: FPU is broken when single-stepping
Product: Virtualization
Version: unspecified
Kernel Version: 5.6
Hardware: PPC-64
OS: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: kvm
Assignee: virtualization_kvm@kernel-bugs.osdl.org
Reporter: cand@gmx.com
Regression: No
The FPU is completely broken when single-stepping on KVM-PR. Registers stay
zeroes, computation results are zeroes. If I disable single-stepping,
computation results are correct, but of course then I cannot dump FPRs between
every instruction.
HW is POWER9, 18-core Talos II.
5.6 is slightly old, but there are no commits under arch/powerpc/kvm since that
mention single stepping.
Program:
https://git.libre-soc.org/?p=kvm-minippc.git;a=summary
Test file:
https://ftp.libre-soc.org/mini-float-test-kvm.bin
Repro instructions:
git clone https://git.libre-soc.org/git/kvm-minippc.git
cd kvm-minippc
make
wget https://ftp.libre-soc.org/mini-float-test-kvm.bin
./kvm-minippc -i mini-float-test-kvm.bin -t trace
less trace
# you will see FPRs stay zeroes. In larger test programs that dump the computed
memory, that is wrong too (all zero).
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next reply other threads:[~2021-05-28 11:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-28 11:20 bugzilla-daemon [this message]
2021-05-31 10:28 ` [Bug 213257] KVM-PR: FPU is broken when single-stepping bugzilla-daemon
2021-06-01 0:12 ` bugzilla-daemon
2021-06-01 7:35 ` bugzilla-daemon
2021-06-01 12:34 ` bugzilla-daemon
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