4.20-stable review patch. If anyone has any objections, please let me know.
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From: Christian Borntraeger borntraeger@de.ibm.com
commit 03aa047ef2db4985e444af6ee1c1dd084ad9fb4c upstream.
Right now the early machine detection code check stsi 3.2.2 for "KVM" and set MACHINE_IS_VM if this is different. As the console detection uses diagnose 8 if MACHINE_IS_VM returns true this will crash Linux early for any non z/VM system that sets a different value than KVM. So instead of assuming z/VM, do not set any of MACHINE_IS_LPAR, MACHINE_IS_VM, or MACHINE_IS_KVM.
CC: stable@vger.kernel.org Reviewed-by: Heiko Carstens heiko.carstens@de.ibm.com Signed-off-by: Christian Borntraeger borntraeger@de.ibm.com Signed-off-by: Martin Schwidefsky schwidefsky@de.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/s390/kernel/early.c | 4 ++-- arch/s390/kernel/setup.c | 2 ++ 2 files changed, 4 insertions(+), 2 deletions(-)
--- a/arch/s390/kernel/early.c +++ b/arch/s390/kernel/early.c @@ -63,10 +63,10 @@ static noinline __init void detect_machi if (stsi(vmms, 3, 2, 2) || !vmms->count) return;
- /* Running under KVM? If not we assume z/VM */ + /* Detect known hypervisors */ if (!memcmp(vmms->vm[0].cpi, "\xd2\xe5\xd4", 3)) S390_lowcore.machine_flags |= MACHINE_FLAG_KVM; - else + else if (!memcmp(vmms->vm[0].cpi, "\xa9\x61\xe5\xd4", 4)) S390_lowcore.machine_flags |= MACHINE_FLAG_VM; }
--- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -1006,6 +1006,8 @@ void __init setup_arch(char **cmdline_p) pr_info("Linux is running under KVM in 64-bit mode\n"); else if (MACHINE_IS_LPAR) pr_info("Linux is running natively in 64-bit mode\n"); + else + pr_info("Linux is running as a guest in 64-bit mode\n");
/* Have one command line that is parsed and saved in /proc/cmdline */ /* boot_command_line has been already set up in early.c */