https://github.com/torvalds/linux
Revision a8b48a4dccea77e29462e59f1dbf0d5aa1ff167c authored by Paul Mackerras on 07 March 2018, 11:17:20 UTC, committed by Paul Mackerras on 14 March 2018, 04:10:50 UTC
This fixes a bug where the trap number that is returned by __kvmppc_vcore_entry gets corrupted. The effect of the corruption is that IPIs get ignored on POWER9 systems when the IPI is sent via a doorbell interrupt to a CPU which is executing in a KVM guest. The effect of the IPI being ignored is often that another CPU locks up inside smp_call_function_many() (and if that CPU is holding a spinlock, other CPUs then lock up inside raw_spin_lock()). The trap number is currently held in register r12 for most of the assembly-language part of the guest exit path. In that path, we call kvmppc_subcore_exit_guest(), which is a C function, without restoring r12 afterwards. Depending on the kernel config and the compiler, it may modify r12 or it may not, so some config/compiler combinations see the bug and others don't. To fix this, we arrange for the trap number to be stored on the stack from the 'guest_bypass:' label until the end of the function, then the trap number is loaded and returned in r12 as before. Cc: stable@vger.kernel.org # v4.8+ Fixes: fd7bacbca47a ("KVM: PPC: Book3S HV: Fix TB corruption in guest exit path on HMI interrupt") Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
1 parent 45e3b47
Tip revision: a8b48a4dccea77e29462e59f1dbf0d5aa1ff167c authored by Paul Mackerras on 07 March 2018, 11:17:20 UTC
KVM: PPC: Book3S HV: Fix trap number return from __kvmppc_vcore_entry
KVM: PPC: Book3S HV: Fix trap number return from __kvmppc_vcore_entry
Tip revision: a8b48a4
File | Mode | Size |
---|---|---|
Documentation | ||
LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.cocciconfig | -rw-r--r-- | 59 bytes |
.get_maintainer.ignore | -rw-r--r-- | 31 bytes |
.gitattributes | -rw-r--r-- | 30 bytes |
.gitignore | -rw-r--r-- | 1.5 KB |
.mailmap | -rw-r--r-- | 8.8 KB |
COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 96.2 KB |
Kbuild | -rw-r--r-- | 2.2 KB |
Kconfig | -rw-r--r-- | 287 bytes |
MAINTAINERS | -rw-r--r-- | 435.6 KB |
Makefile | -rw-r--r-- | 60.2 KB |
README | -rw-r--r-- | 722 bytes |
Computing file changes ...