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| author | Jordan Niethe <jniethe5@gmail.com> | 2019-10-04 12:53:17 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-10-09 17:16:59 +1100 |
| commit | 7fe4e1176dfe47a243d8edd98d26abd11f91b042 (patch) | |
| tree | 2197e9dd2ec96329b5607b5a67d980f2022eb921 /arch/powerpc | |
| parent | 5b216ea1c40cf06eead15054c70e238c9bd4729e (diff) | |
| download | linux-7fe4e1176dfe47a243d8edd98d26abd11f91b042.tar.bz2 | |
powerpc/kvm: Fix kvmppc_vcore->in_guest value in kvmhv_switch_to_host
kvmhv_switch_to_host() in arch/powerpc/kvm/book3s_hv_rmhandlers.S
needs to set kvmppc_vcore->in_guest to 0 to signal secondary CPUs to
continue. This happens after resetting the PCR. Before commit
13c7bb3c57dc ("powerpc/64s: Set reserved PCR bits"), r0 would always
be 0 before it was stored to kvmppc_vcore->in_guest. However because
of this change in the commit:
/* Reset PCR */
ld r0, VCORE_PCR(r5)
- cmpdi r0, 0
+ LOAD_REG_IMMEDIATE(r6, PCR_MASK)
+ cmpld r0, r6
beq 18f
- li r0, 0
- mtspr SPRN_PCR, r0
+ mtspr SPRN_PCR, r6
18:
/* Signal secondary CPUs to continue */
stb r0,VCORE_IN_GUEST(r5)
We are no longer comparing r0 against 0 and loading it with 0 if it
contains something else. Hence when we store r0 to
kvmppc_vcore->in_guest, it might not be 0. This means that secondary
CPUs will not be signalled to continue. Those CPUs get stuck and
errors like the following are logged:
KVM: CPU 1 seems to be stuck
KVM: CPU 2 seems to be stuck
KVM: CPU 3 seems to be stuck
KVM: CPU 4 seems to be stuck
KVM: CPU 5 seems to be stuck
KVM: CPU 6 seems to be stuck
KVM: CPU 7 seems to be stuck
This can be reproduced with:
$ for i in `seq 1 7` ; do chcpu -d $i ; done ;
$ taskset -c 0 qemu-system-ppc64 -smp 8,threads=8 \
-M pseries,accel=kvm,kvm-type=HV -m 1G -nographic -vga none \
-kernel vmlinux -initrd initrd.cpio.xz
Fix by making sure r0 is 0 before storing it to
kvmppc_vcore->in_guest.
Fixes: 13c7bb3c57dc ("powerpc/64s: Set reserved PCR bits")
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191004025317.19340-1-jniethe5@gmail.com
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_rmhandlers.S | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 74a9cfe84aee..faebcbb8c4db 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -1921,6 +1921,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) mtspr SPRN_PCR, r6 18: /* Signal secondary CPUs to continue */ + li r0, 0 stb r0,VCORE_IN_GUEST(r5) 19: lis r8,0x7fff /* MAX_INT@h */ mtspr SPRN_HDEC,r8 |