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Diffstat (limited to 'classification_output/01/instruction/0966902')
| -rw-r--r-- | classification_output/01/instruction/0966902 | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/classification_output/01/instruction/0966902 b/classification_output/01/instruction/0966902 new file mode 100644 index 000000000..80cdabd29 --- /dev/null +++ b/classification_output/01/instruction/0966902 @@ -0,0 +1,39 @@ +instruction: 0.803 +semantic: 0.775 +mistranslation: 0.718 +other: 0.715 + +[Bug] "-ht" flag ignored under KVM - guest still reports HT + +Hi Community, +We have observed that the 'ht' feature bit cannot be disabled when QEMU runs +with KVM acceleration. +qemu-system-x86_64 \ + --enable-kvm \ + -machine q35 \ + -cpu host,-ht \ + -smp 4 \ + -m 4G \ + -drive file=rootfs.img,format=raw \ + -nographic \ + -append 'console=ttyS0 root=/dev/sda rw' +Because '-ht' is specified, the guest should expose no HT capability +(cpuid.1.edx[28] = 0), and /proc/cpuinfo shouldn't show HT feature, but we still +saw ht in linux guest when run 'cat /proc/cpuinfo'. +XiaoYao mentioned that: + +It has been the behavior of QEMU since + + commit 400281af34e5ee6aa9f5496b53d8f82c6fef9319 + Author: Andre Przywara <andre.przywara@amd.com> + Date: Wed Aug 19 15:42:42 2009 +0200 + + set CPUID bits to present cores and threads topology + +that we cannot remove HT CPUID bit from guest via "-cpu xxx,-ht" if the +VM has >= 2 vcpus. +I'd like to know whether there's a plan to address this issue, or if the current +behaviour is considered acceptable. +Best regards, +Ewan. + |