On Thu, 2019-05-02 at 21:09:07 UTC, Gustavo Walbon wrote: > From: "Gustavo L. F. Walbon" <gwal...@linux.ibm.com> > > The issue was showing "Mitigation" message via sysfs whatever the state of > "RFI Flush", but it should show "Vulnerable" when it is disabled. > > If you have "L1D private" feature enabled and not "RFI Flush" you are > vulnerable to meltdown attacks. > > "RFI Flush" is the key feature to mitigate the meltdown whatever the > "L1D private" state. > > SEC_FTR_L1D_THREAD_PRIV is a feature for Power9 only. > > So the message should be as the truth table shows. > CPU | L1D private | RFI Flush | sysfs | > ----| ----------- | --------- | ------------------------------------- | > P9 | False | False | Vulnerable > P9 | False | True | Mitigation: RFI Flush > P9 | True | False | Vulnerable: L1D private per thread > P9 | True | True | Mitigation: RFI Flush, L1D private per > | | | thread > P8 | False | False | Vulnerable > P8 | False | True | Mitigation: RFI Flush > > Output before this fix: > # cat /sys/devices/system/cpu/vulnerabilities/meltdown > Mitigation: RFI Flush, L1D private per thread > # echo 0 > /sys/kernel/debug/powerpc/rfi_flush > # cat /sys/devices/system/cpu/vulnerabilities/meltdown > Mitigation: L1D private per thread > > Output after fix: > # cat /sys/devices/system/cpu/vulnerabilities/meltdown > Mitigation: RFI Flush, L1D private per thread > # echo 0 > /sys/kernel/debug/powerpc/rfi_flush > # cat /sys/devices/system/cpu/vulnerabilities/meltdown > Vulnerable: L1D private per thread > > Link: https://github.com/linuxppc/issues/issues/243 > > Signed-off-by: Gustavo L. F. Walbon <gwal...@linux.ibm.com> > Signed-off-by: Mauro S. M. Rodrigues <maur...@linux.vnet.ibm.com>
Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/4e706af3cd8e1d0503c25332b30cad33c97ed442 cheers