From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier. Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Cc: stable@vger.kernel.org Reported-by: Stefan Teodorescu Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- scripts/extract-vmlinux | 65 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100755 scripts/extract-vmlinux (limited to 'scripts/extract-vmlinux') diff --git a/scripts/extract-vmlinux b/scripts/extract-vmlinux new file mode 100755 index 000000000..266df9bc7 --- /dev/null +++ b/scripts/extract-vmlinux @@ -0,0 +1,65 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-only +# ---------------------------------------------------------------------- +# extract-vmlinux - Extract uncompressed vmlinux from a kernel image +# +# Inspired from extract-ikconfig +# (c) 2009,2010 Dick Streefland +# +# (c) 2011 Corentin Chary +# +# ---------------------------------------------------------------------- + +me=${0##*/} + +check_vmlinux() +{ + if file "$1" | grep -q 'Linux kernel.*boot executable' || + readelf -h "$1" > /dev/null 2>&1 + then + cat "$1" + echo "$me: Extracted vmlinux using '$2' from offset $3" >&2 + exit 0 + fi +} + +try_decompress() +{ + # The obscure use of the "tr" filter is to work around older versions of + # "grep" that report the byte offset of the line instead of the pattern. + + # Try to find the header ($1) and decompress from here + for pos in `tr "$1\n$2" "\n$2=" < "$img" | grep -abo "^$2"` + do + pos=${pos%%:*} + tail -c+$pos "$img" | $3 > $tmp 2> /dev/null + check_vmlinux $tmp "$3" $pos + done +} + +# Check invocation: +img=$1 +if [ $# -ne 1 -o ! -s "$img" ] +then + echo "Usage: $me " >&2 + exit 2 +fi + +# Prepare temp files: +tmp=$(mktemp /tmp/vmlinux-XXX) +trap "rm -f $tmp" 0 + +# That didn't work, so retry after decompression. +try_decompress '\037\213\010' xy gunzip +try_decompress '\3757zXZ\000' abcde unxz +try_decompress 'BZh' xy bunzip2 +try_decompress '\135\0\0\0' xxx unlzma +try_decompress '\211\114\132' xy 'lzop -d' +try_decompress '\002!L\030' xxx 'lz4 -d' +try_decompress '(\265/\375' xxx unzstd + +# Finally check for uncompressed images or objects: +check_vmlinux "$img" cat 0 + +# Bail out: +echo "$me: Cannot find vmlinux." >&2 -- cgit v1.3.1