Bug#887061: linux-image-4.9.0-5-amd64: KPTI (kaiser.c): please, no silent disable for Xen guests
Package: src:linux
Version: 4.9.65-3+deb9u2
Severity: wishlist
Hi,
My VM is a Xen guest, and I was confused not to find any information
about KPTI in the kernel logs. This is due to the silent_disable
case here:
In arch/x86/mm/kaiser.c:
void __init kaiser_check_boottime_disable(void)
{
[...]
if (boot_cpu_has(X86_FEATURE_XENPV))
goto silent_disable;
[...]
disable:
pr_info("disabled\n");
silent_disable:
kaiser_enabled = 0;
setup_clear_cpu_cap(X86_FEATURE_KAISER);
}
It would be better to have some logs, saying that it is disabled and
why (Xen PV).
-- Package-specific info:
** Version:
Linux version 4.9.0-5-amd64 (debian-kernel@lists.debian.org) (gcc version 6.3.0 20170516 (Debian 6.3.0-18) ) #1 SMP Debian 4.9.65-3+deb9u2 (2018-01-04)
** Command line:
root=UUID=2ae1ff60-aeb0-4d39-8a98-ff98d5f63f7e ro console=ttyS0 console=hvc0 nomce loglevel=5 net.ifnames=0
** Not tainted
** Kernel log:
Unable to read kernel log; any relevant messages should be attached
** Model information
** Loaded modules:
ipt_REJECT
nf_reject_ipv4
xt_multiport
iptable_filter
evdev
pcspkr
intel_rapl
sb_edac
edac_core
x86_pkg_temp_thermal
coretemp
crct10dif_pclmul
crc32_pclmul
ghash_clmulni_intel
intel_rapl_perf
ip_tables
x_tables
autofs4
ext4
crc16
jbd2
crc32c_generic
fscrypto
ecb
mbcache
crc32c_intel
aesni_intel
xen_netfront
xen_blkfront
aes_x86_64
glue_helper
lrw
gf128mul
ablk_helper
cryptd
** PCI devices:
not available
** USB devices:
not available
-- System Information:
Debian Release: 9.3
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable-debug'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 4.9.0-5-amd64 (SMP w/1 CPU core)
Locale: LANG=POSIX, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=POSIX (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages linux-image-4.9.0-5-amd64 depends on:
ii initramfs-tools [linux-initramfs-tool] 0.130
ii kmod 23-2
ii linux-base 4.5
Versions of packages linux-image-4.9.0-5-amd64 recommends:
ii firmware-linux-free 3.4
ii irqbalance 1.1.0-2.3
Versions of packages linux-image-4.9.0-5-amd64 suggests:
pn debian-kernel-handbook <none>
ii grub-efi-amd64 2.02~beta3-5
pn linux-doc-4.9 <none>
Versions of packages linux-image-4.9.0-5-amd64 is related to:
pn firmware-amd-graphics <none>
pn firmware-atheros <none>
pn firmware-bnx2 <none>
pn firmware-bnx2x <none>
pn firmware-brcm80211 <none>
pn firmware-cavium <none>
pn firmware-intel-sound <none>
pn firmware-intelwimax <none>
pn firmware-ipw2x00 <none>
pn firmware-ivtv <none>
pn firmware-iwlwifi <none>
pn firmware-libertas <none>
pn firmware-linux-nonfree <none>
pn firmware-misc-nonfree <none>
pn firmware-myricom <none>
pn firmware-netxen <none>
pn firmware-qlogic <none>
pn firmware-realtek <none>
pn firmware-samsung <none>
pn firmware-siano <none>
pn firmware-ti-connectivity <none>
pn xen-hypervisor <none>
-- no debconf information
--
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
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