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 --- arch/m68k/tools/amiga/Makefile | 12 ++++++++ arch/m68k/tools/amiga/dmesg.c | 69 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 81 insertions(+) create mode 100644 arch/m68k/tools/amiga/Makefile create mode 100644 arch/m68k/tools/amiga/dmesg.c (limited to 'arch/m68k/tools') diff --git a/arch/m68k/tools/amiga/Makefile b/arch/m68k/tools/amiga/Makefile new file mode 100644 index 000000000..e6425b367 --- /dev/null +++ b/arch/m68k/tools/amiga/Makefile @@ -0,0 +1,12 @@ +# SPDX-License-Identifier: GPL-2.0 + +CC = m68k-cbm-amigados-gcc +CFLAGS = -Wall -O2 + + +All: dmesg + + +dmesg: dmesg.c + $(CC) $(CFLAGS) -o dmesg dmesg.c -noixemul + diff --git a/arch/m68k/tools/amiga/dmesg.c b/arch/m68k/tools/amiga/dmesg.c new file mode 100644 index 000000000..f8005a7ef --- /dev/null +++ b/arch/m68k/tools/amiga/dmesg.c @@ -0,0 +1,69 @@ +/* + * linux/arch/m68k/tools/amiga/dmesg.c -- Retrieve the kernel messages stored + * in Chip RAM with the kernel command + * line option `debug=mem'. + * + * © Copyright 1996 by Geert Uytterhoeven + * + * + * Usage: + * + * dmesg + * dmesg + * + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of the Linux + * distribution for more details. + */ + + +#include +#include +#include + + +#define CHIPMEM_START 0x00000000 +#define CHIPMEM_END 0x00200000 /* overridden by argv[1] */ + +#define SAVEKMSG_MAGIC1 0x53415645 /* 'SAVE' */ +#define SAVEKMSG_MAGIC2 0x4B4D5347 /* 'KMSG' */ + +struct savekmsg { + u_long magic1; /* SAVEKMSG_MAGIC1 */ + u_long magic2; /* SAVEKMSG_MAGIC2 */ + u_long magicptr; /* address of magic1 */ + u_long size; + char data[]; +}; + + +int main(int argc, char *argv[]) +{ + u_long start = CHIPMEM_START, end = CHIPMEM_END, p; + int found = 0; + struct savekmsg *m = NULL; + + if (argc >= 2) + end = strtoul(argv[1], NULL, 0); + printf("Searching for SAVEKMSG magic...\n"); + for (p = start; p <= end-sizeof(struct savekmsg); p += 4) { + m = (struct savekmsg *)p; + if ((m->magic1 == SAVEKMSG_MAGIC1) && (m->magic2 == SAVEKMSG_MAGIC2) && + (m->magicptr == p)) { + found = 1; + break; + } + } + if (!found) + printf("Not found\n"); + else { + printf("Found %ld bytes at 0x%08lx\n", m->size, (u_long)&m->data); + puts(">>>>>>>>>>>>>>>>>>>>"); + fflush(stdout); + write(1, &m->data, m->size); + fflush(stdout); + puts("<<<<<<<<<<<<<<<<<<<<"); + } + return(0); +} -- cgit v1.3.1