diff options
Diffstat (limited to 'results/scraper/launchpad-without-comments/1904317')
| -rw-r--r-- | results/scraper/launchpad-without-comments/1904317 | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/results/scraper/launchpad-without-comments/1904317 b/results/scraper/launchpad-without-comments/1904317 new file mode 100644 index 000000000..814eb8683 --- /dev/null +++ b/results/scraper/launchpad-without-comments/1904317 @@ -0,0 +1,22 @@ +cpu feature selection is not affected to guest 's cpuid with whpx + +On windows with -accel whpx, "-cpu" is ignored without any messages. +Guest recognizes features as same as host's. + +Confirmed on v5.2.0-rc1. + +I suggest qemu may do, + +- Warn with incompatible -cpu options were given. +- Enhance cpuid handling. + +Background: +I was investigated mmio and block copy issue in Linux kernel. +I met a problem that Linux went ill for touching mmio with whpx. (not with tcg) +I suspect erms(enhanced rep movs) might trigger. +I tried to mask erms on qemu with -feature,erms, but it was ineffective. + +At last, I disabled erms manually, to tweak whpx-all.c to mask erms in cpuid. + +FYI, qemu with whpx from/to mmio, "rep movsb" does byte access regardless of erms. +Linux kernel tends to choose not "rep movsq" but "rep movsb" with erms. \ No newline at end of file |