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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-10-05 08:29:47 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-10-25 07:59:30 +0200 |
| commit | 0a5e2ec2647737907d267c09dc9a25fab1468865 (patch) | |
| tree | b6788e55a1560e921419acaea0ed48772b9ed1e6 /arch/s390/kernel/entry.S | |
| parent | f34157878d3b17641ad2366988600c23c89d98b2 (diff) | |
| download | linux-stable-0a5e2ec2647737907d267c09dc9a25fab1468865.tar.gz linux-stable-0a5e2ec2647737907d267c09dc9a25fab1468865.tar.bz2 linux-stable-0a5e2ec2647737907d267c09dc9a25fab1468865.zip | |
s390/kvm: fix detection of guest machine checks
The new detection code for guest machine checks added a check based
on %r11 to .Lcleanup_sie to distinguish between normal asynchronous
interrupts and machine checks. But the funtion is called from the
program check handler as well with an undefined value in %r11.
The effect is that all program exceptions pointing to the SIE instruction
will set the CIF_MCCK_GUEST bit. The bit stays set for the CPU until the
next machine check comes in which will incorrectly be interpreted as a
guest machine check.
The simplest fix is to stop using .Lcleanup_sie in the program check
handler and duplicate a few instructions.
Fixes: c929500d7a5a ("s390/nmi: s390: New low level handling for machine check happening in guest")
Cc: <stable@vger.kernel.org> # v4.13+
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/entry.S')
| -rw-r--r-- | arch/s390/kernel/entry.S | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 21900e1cee9c..d185aa3965bf 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -521,12 +521,15 @@ ENTRY(pgm_check_handler) tmhh %r8,0x0001 # test problem state bit jnz 2f # -> fault in user space #if IS_ENABLED(CONFIG_KVM) - # cleanup critical section for sie64a + # cleanup critical section for program checks in sie64a lgr %r14,%r9 slg %r14,BASED(.Lsie_critical_start) clg %r14,BASED(.Lsie_critical_length) jhe 0f - brasl %r14,.Lcleanup_sie + lg %r14,__SF_EMPTY(%r15) # get control block pointer + ni __SIE_PROG0C+3(%r14),0xfe # no longer in SIE + lctlg %c1,%c1,__LC_USER_ASCE # load primary asce + larl %r9,sie_exit # skip forward to sie_exit #endif 0: tmhh %r8,0x4000 # PER bit set in old PSW ? jnz 1f # -> enabled, can't be a double fault |