icepick#

kernel module for l3 cache pseudo-locking via cat and wc-mapped i/o space.

overview#

icepick exposes a character device for pinning data into isolated l3 cache ways. maps physical i/o space with write-combining via ioremap_wc and mtrr configuration, then primes cache lines using prefetcht2 and temporal loads. cat schemata configured through resctrl sysfs. pmu-based eviction monitoring via perf_event (amd zen l3 miss counter 0x0104e). useful for side-channel isolation or latency-critical data structures requiring deterministic cache residency.

requires cat-capable silicon (amd zen2+), resctrl mounted, and kernel headers for kbuild.

build#

make

outputs icepick.ko kernel module.

usage#

insmod icepick.ko
chmod 666 /dev/cachemem

echo "sensitive data" > /dev/cachemem    # lock into l3 way 0
cat /dev/cachemem                        # read back, integrity check
dmesg | grep ICEPICK                     # check residency/eviction logs

rmmod icepick

ioctl flush:

#define ICEPICK_IOC_MAGIC 'k'
#define ICEPICK_FLUSH_CACHE _IOW(ICEPICK_IOC_MAGIC, 1, char *)

ioctl(fd, ICEPICK_FLUSH_CACHE, "please flush my cachelines");