[ Upstream commit 20b7035c66 ]
KVM API says for the signal mask you set via KVM_SET_SIGNAL_MASK, that
"any unblocked signal received [...] will cause KVM_RUN to return with
-EINTR" and that "the signal will only be delivered if not blocked by
the original signal mask".
This, however, is only true, when the calling task has a signal handler
registered for a signal. If not, signal evaluation is short-circuited for
SIG_IGN and SIG_DFL, and the signal is either ignored without KVM_RUN
returning or the whole process is terminated.
Make KVM_SET_SIGNAL_MASK behave as advertised by utilizing logic similar
to that in do_sigtimedwait() to avoid short-circuiting of signals.
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6e032b350c upstream.
New device-tree properties are available which tell the hypervisor
settings related to the RFI flush. Use them to determine the
appropriate flush instruction to use, and whether the flush is
required.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8989d56878 upstream.
A new hypervisor call is available which tells the guest settings
related to the RFI flush. Use it to query the appropriate flush
instruction(s), and whether the flush is required.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bc9c9304a4 upstream.
Because there may be some performance overhead of the RFI flush, add
kernel command line options to disable it.
We add a sensibly named 'no_rfi_flush' option, but we also hijack the
x86 option 'nopti'. The RFI flush is not the same as KPTI, but if we
see 'nopti' we can guess that the user is trying to avoid any overhead
of Meltdown mitigations, and it means we don't have to educate every
one about a different command line option.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit aa8a5e0062 upstream.
On some CPUs we can prevent the Meltdown vulnerability by flushing the
L1-D cache on exit from kernel to user mode, and from hypervisor to
guest.
This is known to be the case on at least Power7, Power8 and Power9. At
this time we do not know the status of the vulnerability on other CPUs
such as the 970 (Apple G5), pasemi CPUs (AmigaOne X1000) or Freescale
CPUs. As more information comes to light we can enable this, or other
mechanisms on those CPUs.
The vulnerability occurs when the load of an architecturally
inaccessible memory region (eg. userspace load of kernel memory) is
speculatively executed to the point where its result can influence the
address of a subsequent speculatively executed load.
In order for that to happen, the first load must hit in the L1,
because before the load is sent to the L2 the permission check is
performed. Therefore if no kernel addresses hit in the L1 the
vulnerability can not occur. We can ensure that is the case by
flushing the L1 whenever we return to userspace. Similarly for
hypervisor vs guest.
In order to flush the L1-D cache on exit, we add a section of nops at
each (h)rfi location that returns to a lower privileged context, and
patch that with some sequence. Newer firmwares are able to advertise
to us that there is a special nop instruction that flushes the L1-D.
If we do not see that advertised, we fall back to doing a displacement
flush in software.
For guest kernels we support migration between some CPU versions, and
different CPUs may use different flush instructions. So that we are
prepared to migrate to a machine with a different flush instruction
activated, we may have to patch more than one flush instruction at
boot if the hypervisor tells us to.
In the end this patch is mostly the work of Nicholas Piggin and
Michael Ellerman. However a cast of thousands contributed to analysis
of the issue, earlier versions of the patch, back ports testing etc.
Many thanks to all of them.
Tested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c7305645eb upstream.
In the SLB miss handler we may be returning to user or kernel. We need
to add a check early on and save the result in the cr4 register, and
then we bifurcate the return path based on that.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a08f828cf4 upstream.
Similar to the syscall return path, in fast_exception_return we may be
returning to user or kernel context. We already have a test for that,
because we conditionally restore r13. So use that existing test and
branch, and bifurcate the return based on that.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b8e90cb7bc upstream.
In the syscall exit path we may be returning to user or kernel
context. We already have a test for that, because we conditionally
restore r13. So use that existing test and branch, and bifurcate the
return based on that.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 222f20f140 upstream.
This commit does simple conversions of rfi/rfid to the new macros that
include the expected destination context. By simple we mean cases
where there is a single well known destination context, and it's
simply a matter of substituting the instruction for the appropriate
macro.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 50e51c13b3 upstream.
The rfid/hrfid ((Hypervisor) Return From Interrupt) instruction is
used for switching from the kernel to userspace, and from the
hypervisor to the guest kernel. However it can and is also used for
other transitions, eg. from real mode kernel code to virtual mode
kernel code, and it's not always clear from the code what the
destination context is.
To make it clearer when reading the code, add macros which encode the
expected destination context.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 191eccb158 upstream.
A new hypervisor call has been defined to communicate various
characteristics of the CPU to guests. Add definitions for the hcall
number, flags and a wrapper function.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ecba8297aa upstream.
The KVM_PPC_ALLOCATE_HTAB ioctl(), implemented by kvmppc_alloc_reset_hpt()
is supposed to completely clear and reset a guest's Hashed Page Table (HPT)
allocating or re-allocating it if necessary.
In the case where an HPT of the right size already exists and it just
zeroes it, it forces a TLB flush on all guest CPUs, to remove any stale TLB
entries loaded from the old HPT.
However, that situation can arise when the HPT is resizing as well - or
even when switching from an RPT to HPT - so those cases need a TLB flush as
well.
So, move the TLB flush to trigger in all cases except for errors.
Fixes: f98a8bf9ee ("KVM: PPC: Book3S HV: Allow KVM_PPC_ALLOCATE_HTAB ioctl() to change HPT size")
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4ed11aeefd upstream.
When serving multiple resize requests following could happen:
CPU0 CPU1
---- ----
kvm_vm_ioctl_resize_hpt_prepare(1);
-> schedule_work()
/* system_rq might be busy: delay */
kvm_vm_ioctl_resize_hpt_prepare(2);
mutex_lock();
if (resize) {
...
release_hpt_resize();
}
... resize_hpt_prepare_work()
-> schedule_work() {
mutex_unlock() /* resize->kvm could be wrong */
struct kvm *kvm = resize->kvm;
mutex_lock(&kvm->lock); <<<< UAF
...
}
i.e. a second resize request with different order could be started by
kvm_vm_ioctl_resize_hpt_prepare(), causing the previous request to be
free()d when there's still an active worker thread which will try to
access it. This leads to a use after free in point marked with UAF on
the diagram above.
To prevent this from happening, instead of unconditionally releasing a
pre-existing resize structure from the prepare ioctl(), we check if
the existing structure has an in-progress worker. We do that by
checking if the resize->error == -EBUSY, which is safe because the
resize->error field is protected by the kvm->lock. If there is an
active worker, instead of releasing, we mark the structure as stale by
unlinking it from kvm_struct.
In the worker thread we check for a stale structure (with kvm->lock
held), and in that case abort, releasing the stale structure ourself.
We make the check both before and the actual allocation. Strictly,
only the check afterwards is needed, the check before is an
optimization: if the structure happens to become stale before the
worker thread is dispatched, rather than during the allocation, it
means we can avoid allocating then immediately freeing a potentially
substantial amount of memory.
This fixes following or similar host kernel crash message:
[ 635.277361] Unable to handle kernel paging request for data at address 0x00000000
[ 635.277438] Faulting instruction address: 0xc00000000052f568
[ 635.277446] Oops: Kernel access of bad area, sig: 11 [#1]
[ 635.277451] SMP NR_CPUS=2048 NUMA PowerNV
[ 635.277470] Modules linked in: xt_CHECKSUM iptable_mangle ipt_MASQUERADE
nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4
nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 tun bridge stp llc
ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter nfsv3 nfs_acl nfs
lockd grace fscache kvm_hv kvm rpcrdma sunrpc ib_isert iscsi_target_mod ib_iser libiscsi
scsi_transport_iscsi ib_srpt target_core_mod ext4 ib_srp scsi_transport_srp
ib_ipoib mbcache jbd2 rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm ocrdma(T)
ib_core ses enclosure scsi_transport_sas sg shpchp leds_powernv ibmpowernv i2c_opal
i2c_core powernv_rng ipmi_powernv ipmi_devintf ipmi_msghandler ip_tables xfs
libcrc32c sr_mod sd_mod cdrom lpfc nvme_fc(T) nvme_fabrics nvme_core ipr nvmet_fc(T)
tg3 nvmet libata be2net crc_t10dif crct10dif_generic scsi_transport_fc ptp scsi_tgt
pps_core crct10dif_common dm_mirror dm_region_hash dm_log dm_mod
[ 635.278687] CPU: 40 PID: 749 Comm: kworker/40:1 Tainted: G
------------ T 3.10.0.bz1510771+ #1
[ 635.278782] Workqueue: events resize_hpt_prepare_work [kvm_hv]
[ 635.278851] task: c0000007e6840000 ti: c0000007e9180000 task.ti: c0000007e9180000
[ 635.278919] NIP: c00000000052f568 LR: c0000000009ea310 CTR: c0000000009ea4f0
[ 635.278988] REGS: c0000007e91837f0 TRAP: 0300 Tainted: G
------------ T (3.10.0.bz1510771+)
[ 635.279077] MSR: 9000000100009033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: 24002022 XER:
00000000
[ 635.279248] CFAR: c000000000009368 DAR: 0000000000000000 DSISR: 40000000 SOFTE: 1
GPR00: c0000000009ea310 c0000007e9183a70 c000000001250b00 c0000007e9183b10
GPR04: 0000000000000000 0000000000000000 c0000007e9183650 0000000000000000
GPR08: c0000007ffff7b80 00000000ffffffff 0000000080000028 d00000000d2529a0
GPR12: 0000000000002200 c000000007b56800 c000000000120028 c0000007f135bb40
GPR16: 0000000000000000 c000000005c1e018 c000000005c1e018 0000000000000000
GPR20: 0000000000000001 c0000000011bf778 0000000000000001 fffffffffffffef7
GPR24: 0000000000000000 c000000f1e262e50 0000000000000002 c0000007e9180000
GPR28: c000000f1e262e4c c000000f1e262e50 0000000000000000 c0000007e9183b10
[ 635.280149] NIP [c00000000052f568] __list_add+0x38/0x110
[ 635.280197] LR [c0000000009ea310] __mutex_lock_slowpath+0xe0/0x2c0
[ 635.280253] Call Trace:
[ 635.280277] [c0000007e9183af0] [c0000000009ea310] __mutex_lock_slowpath+0xe0/0x2c0
[ 635.280356] [c0000007e9183b70] [c0000000009ea554] mutex_lock+0x64/0x70
[ 635.280426] [c0000007e9183ba0] [d00000000d24da04]
resize_hpt_prepare_work+0xe4/0x1c0 [kvm_hv]
[ 635.280507] [c0000007e9183c40] [c000000000113c0c] process_one_work+0x1dc/0x680
[ 635.280587] [c0000007e9183ce0] [c000000000114250] worker_thread+0x1a0/0x520
[ 635.280655] [c0000007e9183d80] [c00000000012010c] kthread+0xec/0x100
[ 635.280724] [c0000007e9183e30] [c00000000000a4b8] ret_from_kernel_thread+0x5c/0xa4
[ 635.280814] Instruction dump:
[ 635.280880] 7c0802a6 fba1ffe8 fbc1fff0 7cbd2b78 fbe1fff8 7c9e2378 7c7f1b78
f8010010
[ 635.281099] f821ff81 e8a50008 7fa52040 40de00b8 <e8be0000> 7fbd2840 40de008c
7fbff040
[ 635.281324] ---[ end trace b628b73449719b9d ]---
Fixes: b5baa68773 ("KVM: PPC: Book3S HV: KVM-HV HPT resizing implementation")
Signed-off-by: Serhii Popovych <spopovyc@redhat.com>
[dwg: Replaced BUG_ON()s with WARN_ONs() and reworded commit message
for clarity]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3073774e63 upstream.
Currently the kvm_resize_hpt structure has two fields relevant to the
state of an ongoing resize: 'prepare_done', which indicates whether
the worker thread has completed or not, and 'error' which indicates
whether it was successful or not.
Since the success/failure isn't known until completion, this is
confusingly redundant. This patch consolidates the information into
just the 'error' value: -EBUSY indicates the worked is still in
progress, other negative values indicate (completed) failure, 0
indicates successful completion.
As a bonus this reduces size of struct kvm_resize_hpt by
__alignof__(struct kvm_hpt_info) and saves few bytes of code.
While there correct comment in struct kvm_resize_hpt which references
a non-existent semaphore (leftover from an early draft).
Assert with WARN_ON() in case of HPT allocation thread work runs more
than once for resize request or resize_hpt_allocate() returns -EBUSY
that is treated specially.
Change comparison against zero to make checkpatch.pl happy.
Signed-off-by: Serhii Popovych <spopovyc@redhat.com>
[dwg: Changed BUG_ON()s to WARN_ON()s and altered commit message for
clarity]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6c7d47c33e upstream.
Commit 96df226 ("KVM: PPC: Book3S PR: Preserve storage control bits")
added code to preserve WIMG bits but it missed 2 special cases:
- a magic page in kvmppc_mmu_book3s_64_xlate() and
- guest real mode in kvmppc_handle_pagefault().
For these ptes, WIMG was 0 and pHyp failed on these causing a guest to
stop in the very beginning at NIP=0x100 (due to bd9166ffe "KVM: PPC:
Book3S PR: Exit KVM on failed mapping").
According to LoPAPR v1.1 14.5.4.1.2 H_ENTER:
The hypervisor checks that the WIMG bits within the PTE are appropriate
for the physical page number else H_Parameter return. (For System Memory
pages WIMG=0010, or, 1110 if the SAO option is enabled, and for IO pages
WIMG=01**.)
This hence initializes WIMG to non-zero value HPTE_R_M (0x10), as expected
by pHyp.
[paulus@ozlabs.org - fix compile for 32-bit]
Fixes: 96df226 "KVM: PPC: Book3S PR: Preserve storage control bits"
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Tested-by: Ruediger Oertel <ro@suse.de>
Reviewed-by: Greg Kurz <groug@kaod.org>
Tested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f41d84dddc upstream.
It's theoretically possible that branch instructions recorded in
BHRB (Branch History Rolling Buffer) entries have already been
unmapped before they are processed by the kernel. Hence, trying to
dereference such memory location will result in a crash. eg:
Unable to handle kernel paging request for data at address 0xd000000019c41764
Faulting instruction address: 0xc000000000084a14
NIP [c000000000084a14] branch_target+0x4/0x70
LR [c0000000000eb828] record_and_restart+0x568/0x5c0
Call Trace:
[c0000000000eb3b4] record_and_restart+0xf4/0x5c0 (unreliable)
[c0000000000ec378] perf_event_interrupt+0x298/0x460
[c000000000027964] performance_monitor_exception+0x54/0x70
[c000000000009ba4] performance_monitor_common+0x114/0x120
Fix it by deferefencing the addresses safely.
Fixes: 691231846c ("powerpc/perf: Fix setting of "to" addresses for BHRB")
Suggested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
[mpe: Use probe_kernel_read() which is clearer, tweak change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7333b5aca4 upstream.
When we migrate a VM from a POWER8 host (XICS) to a POWER9 host
(XICS-on-XIVE), we have an error:
qemu-kvm: Unable to restore KVM interrupt controller state \
(0xff000000) for CPU 0: Invalid argument
This is because kvmppc_xics_set_icp() checks the new state
is internaly consistent, and especially:
...
1129 if (xisr == 0) {
1130 if (pending_pri != 0xff)
1131 return -EINVAL;
...
On the other side, kvmppc_xive_get_icp() doesn't set
neither the pending_pri value, nor the xisr value (set to 0)
(and kvmppc_xive_set_icp() ignores the pending_pri value)
As xisr is 0, pending_pri must be set to 0xff.
Fixes: 5af5099385 ("KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller")
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit dc1c4165d1 upstream.
When restoring a pending interrupt, we are setting the Q bit to force
a retrigger in xive_finish_unmask(). But we also need to force an EOI
in this case to reach the same initial state : P=1, Q=0.
This can be done by not setting 'old_p' for pending interrupts which
will inform xive_finish_unmask() that an EOI needs to be sent.
Fixes: 5af5099385 ("KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller")
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Tested-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 87338c8e2c ]
The assumption of unconditionally reloading skb pointers on
BPF helper calls where bpf_helper_changes_pkt_data() holds
true is wrong. There can be different contexts where the helper
would enforce a reload such as in case of XDP. Here, we do
have a struct xdp_buff instead of struct sk_buff as context,
thus this will access garbage.
JITs only ever need to deal with cached skb pointer reload
when ld_abs/ind was seen, therefore guard the reload behind
SEEN_SKB.
Fixes: 156d0e290e ("powerpc/ebpf/jit: Implement JIT compiler for extended BPF")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 80e4d70b06 ]
In xmon, touch_nmi_watchdog() is not expected to be checking that
other CPUs have not touched the watchdog, so the code will just call
touch_nmi_watchdog() once before re-enabling hard interrupts.
Just update our CPU's state, and ignore apparently stuck SMP threads.
Arguably touch_nmi_watchdog should check for SMP lockups, and callers
should be fixed, but that's not trivial for the input code of xmon.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 064996d62a ]
The SMP hardlockup watchdog cross-checks other CPUs for lockups, which
causes xmon headaches because it's assuming interrupts hard disabled
means no watchdog troubles. Try to improve that by calling
touch_nmi_watchdog() in obvious places where secondaries are spinning.
Also annotate these spin loops with spin_begin/end calls.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 402e172a2c ]
Currently xmon could call XIVE functions from OPAL even if the XIVE is
disabled or does not exist in the system, as in POWER8 machines. This
causes the following exception:
1:mon> dx
cpu 0x1: Vector: 700 (Program Check) at [c000000423c93450]
pc: c00000000009cfa4: opal_xive_dump+0x50/0x68
lr: c0000000000997b8: opal_return+0x0/0x50
This patch simply checks if XIVE is enabled before calling XIVE
functions.
Fixes: 243e25112d ("powerpc/xive: Native exploitation of the XIVE interrupt controller")
Suggested-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 05c14c0313 ]
In the hv-24x7 code there is a function memord() which tries to
implement a sort function return -1, 0, 1. However one of the
conditions is incorrect, such that it can never be true, because we
will have already returned.
I don't believe there is a bug in practice though, because the
comparisons are an optimisation prior to calling memcmp().
Fix it by swapping the second comparision, so it can be true.
Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit b8f89fea59 ]
When a vdevice is DLPAR removed from the system the vio subsystem
doesn't bother unmapping the virq from the irq_domain. As a result we
have a virq mapped to a hardware irq that is no longer valid for the
irq_domain. A side effect is that we are left with /proc/irq/<irq#>
affinity entries, and attempts to modify the smp_affinity of the irq
will fail.
In the following observed example the kernel log is spammed by
ics_rtas_set_affinity errors after the removal of a VSCSI adapter.
This is a result of irqbalance trying to adjust the affinity every 10
seconds.
rpadlpar_io: slot U8408.E8E.10A7ACV-V5-C25 removed
ics_rtas_set_affinity: ibm,set-xive irq=655385 returns -3
ics_rtas_set_affinity: ibm,set-xive irq=655385 returns -3
This patch fixes the issue by calling irq_dispose_mapping() on the
virq of the viodev on unregister.
Fixes: f2ab621996 ("powerpc/pseries: Add PFO support to the VIO bus")
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 6b148a7ce7 ]
IPIC Status is provided by register IPIC_SERSR and not by IPIC_SERMR
which is the mask register.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 71e24d7731 ]
The current code checks the completion map to look for the first token
that is complete. In some cases, a completion can come in but the
token can still be on lease to the caller processing the completion.
If this completed but unreleased token is the first token found in the
bitmap by another tasks trying to acquire a token, then the
__test_and_set_bit call will fail since the token will still be on
lease. The acquisition will then fail with an EBUSY.
This patch reorganizes the acquisition code to look at the
opal_async_token_map for an unleased token. If the token has no lease
it must have no outstanding completions so we should never see an
EBUSY, unless we have leased out too many tokens. Since
opal_async_get_token_inrerruptible is protected by a semaphore, we
will practically never see EBUSY anymore.
Fixes: 8d72482322 ("powerpc/powernv: Infrastructure to support OPAL async completion")
Signed-off-by: William A. Kennington III <wak@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit cd77b5ce20 ]
The call to /proc/cpuinfo in turn calls cpufreq_quick_get() which
returns the last frequency requested by the kernel, but may not
reflect the actual frequency the processor is running at. This patch
makes a call to cpufreq_get() instead which returns the current
frequency reported by the hardware.
Fixes: fb5153d05a ("powerpc: powernv: Implement ppc_md.get_proc_freq()")
Signed-off-by: Shriya <shriyak@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4d2dc2cc76 upstream.
Currently, we're capping the values too low in the F_GETLK64 case. The
fields in that structure are 64-bit values, so we shouldn't need to do
any sort of fixup there.
Make sure we check that assumption at build time in the future however
by ensuring that the sizes we're copying will fit.
With this, we no longer need COMPAT_LOFF_T_MAX either, so remove it.
Fixes: 94073ad77f (fs/locks: don't mess with the address limit in compat_fcntl64)
Reported-by: Vitaly Lipatov <lav@etersoft.ru>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit de34787f10 ]
"pmu_count" in opal_imc_counters_probe() is intended to hold
the number of successful nest imc pmu registerations. But
current code also counts other imc units like core_imc and
thread_imc. Patch add a check to count only nest imc pmus.
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 371b80447f upstream.
kexec can leave MMU registers set when booting into a new kernel,
the PIDR (Process Identification Register) in particular. The boot
sequence does not zero PIDR, so it only gets set when CPUs first
switch to a userspace processes (until then it's running a kernel
thread with effective PID = 0).
This leaves a window where a process table entry and page tables are
set up due to user processes running on other CPUs, that happen to
match with a stale PID. The CPU with that PID may cause speculative
accesses that address quadrant 0 (aka userspace addresses), which will
result in cached translations and PWC (Page Walk Cache) for that
process, on a CPU which is not in the mm_cpumask and so they will not
be invalidated properly.
The most common result is the kernel hanging in infinite page fault
loops soon after kexec (usually in schedule_tail, which is usually the
first non-speculative quadrant 0 access to a new PID) due to a stale
PWC. However being a stale translation error, it could result in
anything up to security and data corruption problems.
Fix this by zeroing out PIDR at boot and kexec.
Fixes: 7e381c0ff6 ("powerpc/mm/radix: Add mmu context handling callback for radix")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ab9dbf771f upstream.
This reverts commit a3b2cb30f2.
That commit tried to fix problems with panic on powerpc in certain
circumstances, where some output from the generic panic code was being
dropped.
Unfortunately, it breaks things worse in other circumstances. In
particular when running a PAPR guest, it will now attempt to reboot
instead of informing the hypervisor (KVM or PowerVM) that the guest
has crashed. The crash notification is important to some
virtualization management layers.
Revert it for now until we can come up with a better solution.
Fixes: a3b2cb30f2 ("powerpc: Do not call ppc_md.panic in fadump panic notifier")
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[mpe: Tweak change log a bit]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8a2d71a3f2 upstream.
Per Documentation/kprobes.txt, probe handlers need to be invoked with
preemption disabled. Update optimized_callback() to do so. Also move
get_kprobe_ctlblk() invocation post preemption disable, since it
accesses pre-cpu data.
This was not an issue so far since optprobes wasn't selected if
CONFIG_PREEMPT was enabled. Commit a30b85df7d ("kprobes: Use
synchronize_rcu_tasks() for optprobe with CONFIG_PREEMPT=y") changes
this.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2621e945fb upstream.
The code that cleans up the IAMR/AMOR before kexec'ing failed to
remember that when we're running as a guest AMOR is not writable, it's
hypervisor privileged.
They symptom is that the kexec stops before entering purgatory and
nothing else is seen on the console. If you examine the state of the
system all threads will be in the 0x700 program check handler.
Fix it by making the write to AMOR dependent on HV mode.
Fixes: 1e2a516e89 ("powerpc/kexec: Fix radix to hash kexec due to IAMR/AMOR")
Reported-by: Yilin Zhang <yilzhang@redhat.com>
Debugged-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a3961f824c upstream.
Rebooting into a new kernel with kexec fails in trace_tlbie() which is
called from native_hpte_clear(). This happens if the running kernel
has CONFIG_LOCKDEP enabled. With lockdep enabled, the tracepoints
always execute few RCU checks regardless of whether tracing is on or
off. We are already in the last phase of kexec sequence in real mode
with HILE_BE set. At this point the RCU check ends up in
RCU_LOCKDEP_WARN and causes kexec to fail.
Fix this by not calling trace_tlbie() from native_hpte_clear().
mpe: It's not safe to call trace points at this point in the kexec
path, even if we could avoid the RCU checks/warnings. The only
solution is to not call them.
Fixes: 0428491cba ("powerpc/mm: Trace tlbie(l) instructions")
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 35602f82d0 upstream.
While mapping hints with a length that cross 128TB are disallowed,
MAP_FIXED allocations that cross 128TB are allowed. These are failing
on hash (on radix they succeed). Add an additional case for fixed
mappings to expand the addr_limit when crossing 128TB.
Fixes: f4ea6dcb08 ("powerpc/mm: Enable mappings above 128TB")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit effc1b2508 upstream.
Hash unconditionally resets the addr_limit to default (128TB) when the
mm context is initialised. If a process has > 128TB mappings when it
forks, the child will not get the 512TB addr_limit, so accesses to
valid > 128TB mappings will fail in the child.
Fix this by only resetting the addr_limit to default if it was 0. Non
zero indicates it was duplicated from the parent (0 means exec()).
Fixes: f4ea6dcb08 ("powerpc/mm: Enable mappings above 128TB")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6a72dc038b upstream.
When allocating VA space with a hint that crosses 128TB, the SLB
addr_limit variable is not expanded if addr is not > 128TB, but the
slice allocation looks at task_size, which is 512TB. This results in
slice_check_fit() incorrectly succeeding because the slice_count
truncates off bit 128 of the requested mask, so the comparison to the
available mask succeeds.
Fix this by using mm->context.addr_limit instead of mm->task_size for
testing allocation limits. This causes such allocations to fail.
Fixes: f4ea6dcb08 ("powerpc/mm: Enable mappings above 128TB")
Reported-by: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7ece370996 upstream.
Currently userspace is able to request mmap() search between 128T-512T
by specifying a hint address that is greater than 128T. But that means
a hint of 128T exactly will return an address below 128T, which is
confusing and wrong.
So fix the logic to check the hint is greater than *or equal* to 128T.
Fixes: f4ea6dcb08 ("powerpc/mm: Enable mappings above 128TB")
Suggested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Suggested-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Split out of Nick's bigger patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 85e3f1adcb upstream.
Radix VA space allocations test addresses against mm->task_size which
is 512TB, even in cases where the intention is to limit allocation to
below 128TB.
This results in mmap with a hint address below 128TB but address +
length above 128TB succeeding when it should fail (as hash does after
the previous patch).
Set the high address limit to be considered up front, and base
subsequent allocation checks on that consistently.
Fixes: f4ea6dcb08 ("powerpc/mm: Enable mappings above 128TB")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 475b581ff5 upstream.
On 64-bit Book3s, when we take an instruction fault the reason for the
fault may be reported in SRR1. For data faults the reason is reported
in DSISR (Data Storage Instruction Status Register).
The reasons reported in each do not necessarily correspond, so we mask
the SRR1 bits before copying them to the DSISR, which is then used by
the page fault code.
Prior to commit b4c001dc44 ("powerpc/mm: Use symbolic constants for
filtering SRR1 bits on ISIs") we used a hard-coded mask of 0x58200000,
which corresponds to:
DSISR_NOHPTE 0x40000000 /* no translation found */
DSISR_NOEXEC_OR_G 0x10000000 /* exec of no-exec or guarded */
DSISR_PROTFAULT 0x08000000 /* protection fault */
DSISR_KEYFAULT 0x00200000 /* Storage Key fault */
That commit added a #define for the mask, DSISR_SRR1_MATCH_64S, but
incorrectly used a different similarly named DSISR_BAD_FAULT_64S.
This had the effect of changing the mask to 0xa43a0000, which omits
everything but DSISR_KEYFAULT.
Luckily this had no visible effect, because in practice we hardly use
the DSISR bits. The lack of DSISR_NOHPTE means a TLB flush
optimisation was missed in the native HPTE code, and DSISR_NOEXEC_OR_G
and DSISR_PROTFAULT are both only used to trigger rare warnings.
So we got lucky, but let's fix it. The new value only has bits between
17 and 30 set, so we can continue to use andis.
Fixes: b4c001dc44 ("powerpc/mm: Use symbolic constants for filtering SRR1 bits on ISIs")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 46725b17f1 upstream.
When a uprobe is installed on an instruction that we currently do not
emulate, we copy the instruction into a xol buffer and single step
that instruction. If that instruction generates a fault, we abort the
single stepping before invoking the signal handler. Once the signal
handler is done, the uprobe trap is hit again since the instruction is
retried and the process repeats.
We use uprobe_deny_signal() to detect if the xol instruction triggered
a signal. If so, we clear TIF_SIGPENDING and set TIF_UPROBE so that the
signal is not handled until after the single stepping is aborted. In
this case, uprobe_deny_signal() returns true and get_signal() ends up
returning 0. However, in do_signal(), we are not looking at the return
value, but depending on ksig.sig for further action, all with an
uninitialized ksig that is not touched in this scenario. Fix the same
by initializing ksig.sig to 0.
Fixes: 129b69df9c ("powerpc: Use get_signal() signal_setup_done()")
Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f3f1dfd600 upstream.
init_imc_pmu() uses topology_physical_package_id() to detect the
node id of the processor it is on to get local memory, but that's
wrong, and can lead to crashes. Fix it to use cpu_to_node().
Fixes: 885dcd709b ("powerpc/perf: Add nest IMC PMU support")
Reported-By: Rob Lippert <rlippert@google.com>
Tested-By: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f79ad50ea3 upstream.
When using the radix MMU on Power9 DD1, to work around a hardware
problem, radix__pte_update() is required to do a two stage update of
the PTE. First we write a zero value into the PTE, then we flush the
TLB, and then we write the new PTE value.
In the normal case that works OK, but it does not work if we're
updating the PTE that maps the code we're executing, because the
mapping is removed by the TLB flush and we can no longer execute from
it. Unfortunately the STRICT_RWX code needs to do exactly that.
The exact symptoms when we hit this case vary, sometimes we print an
oops and then get stuck after that, but I've also seen a machine just
get stuck continually page faulting with no oops printed. The variance
is presumably due to the exact layout of the text and the page size
used for the mappings. In all cases we are unable to boot to a shell.
There are possible solutions such as creating a second mapping of the
TLB flush code, executing from that, and then jumping back to the
original. However we don't want to add that level of complexity for a
DD1 work around.
So just detect that we're running on Power9 DD1 and refrain from
changing the permissions, effectively disabling STRICT_RWX on Power9
DD1.
Fixes: 7614ff3272 ("powerpc/mm/radix: Implement STRICT_RWX/mark_rodata_ro() for Radix")
Reported-by: Andrew Jeffery <andrew@aj.id.au>
[Changelog as suggested by Michael Ellerman <mpe@ellerman.id.au>]
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 252eb55816 upstream.
On powerpc32, patch_instruction() is called by apply_feature_fixups()
which is called from early_init()
There is the following note in front of early_init():
* Note that the kernel may be running at an address which is different
* from the address that it was linked at, so we must use RELOC/PTRRELOC
* to access static data (including strings). -- paulus
Therefore, slab_is_available() cannot be called yet, and
text_poke_area must be addressed with PTRRELOC()
Fixes: 95902e6c88 ("powerpc/mm: Implement STRICT_KERNEL_RWX on PPC32")
Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 00bb6ae500 upstream.
When running a guest on a POWER9 system with the in-kernel XICS
emulation disabled (for example by running QEMU with the parameter
"-machine pseries,kernel_irqchip=off"), the kernel does not pass
the XICS-related hypercalls such as H_CPPR up to userspace for
emulation there as it should.
The reason for this is that the real-mode handlers for these
hypercalls don't check whether a XICS device has been instantiated
before calling the xics-on-xive code. That code doesn't check
either, leading to potential NULL pointer dereferences because
vcpu->arch.xive_vcpu is NULL. Those dereferences won't cause an
exception in real mode but will lead to kernel memory corruption.
This fixes it by adding kvmppc_xics_enabled() checks before calling
the XICS functions.
Fixes: 5af5099385 ("KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Just one fix here for a host crash that can occur with HV KVM
as a result of resizing the guest hashed page table (HPT).
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABAgAGBQJaApLVAAoJEJ2a6ncsY3GfNfcIAJk93C9FK6k2urAORP3lDmKy
P6a4LnkMrQTuUCBGrkP4F1hGq2vpH6o/KeoEdhAgLMHHsarzMyBc5N7rHMHgZUzI
bUna0LaXtjdb5IP0kcDb8HmulmBaFiMf+sa2i3dIW3sCxtvqzzmxOluR0C29fG1I
gTdJV0XDzhQHJLixcQ3i4pi/K6b+wzXrY7fFPMpI2Wji6cKYr0ZL0fG8bQ0pV4OZ
0YgV9sR8mVN17JKU9R4GYz9fkp3+cXDG4xBVtczDlK6TJzF2XVUGgY/iJLMAyDRw
9gcEiIc+khkqyfuQt8iYBiHqRJ7HiT4yX1LMI9dM2vTZi23zsG3yTmsIc16QZLg=
=MzO/
-----END PGP SIGNATURE-----
Merge tag 'kvm-ppc-fixes-4.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
PPC KVM fixes for 4.14
Just one fix here for a host crash that can occur with HV KVM
as a result of resizing the guest hashed page table (HPT).
Commit 5e9859699a ("KVM: PPC: Book3S HV: Outline of KVM-HV HPT resizing
implementation", 2016-12-20) added code that tries to exclude any use
or update of the hashed page table (HPT) while the HPT resizing code
is iterating through all the entries in the HPT. It does this by
taking the kvm->lock mutex, clearing the kvm->arch.hpte_setup_done
flag and then sending an IPI to all CPUs in the host. The idea is
that any VCPU task that tries to enter the guest will see that the
hpte_setup_done flag is clear and therefore call kvmppc_hv_setup_htab_rma,
which also takes the kvm->lock mutex and will therefore block until
we release kvm->lock.
However, any VCPU that is already in the guest, or is handling a
hypervisor page fault or hypercall, can re-enter the guest without
rechecking the hpte_setup_done flag. The IPI will cause a guest exit
of any VCPUs that are currently in the guest, but does not prevent
those VCPU tasks from immediately re-entering the guest.
The result is that after resize_hpt_rehash_hpte() has made a HPTE
absent, a hypervisor page fault can occur and make that HPTE present
again. This includes updating the rmap array for the guest real page,
meaning that we now have a pointer in the rmap array which connects
with pointers in the old rev array but not the new rev array. In
fact, if the HPT is being reduced in size, the pointer in the rmap
array could point outside the bounds of the new rev array. If that
happens, we can get a host crash later on such as this one:
[91652.628516] Unable to handle kernel paging request for data at address 0xd0000000157fb10c
[91652.628668] Faulting instruction address: 0xc0000000000e2640
[91652.628736] Oops: Kernel access of bad area, sig: 11 [#1]
[91652.628789] LE SMP NR_CPUS=1024 NUMA PowerNV
[91652.628847] Modules linked in: binfmt_misc vhost_net vhost tap xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat ebtable_broute bridge stp llc ip6table_mangle ip6table_security ip6table_raw iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack libcrc32c iptable_mangle iptable_security iptable_raw ebtable_filter ebtables ip6table_filter ip6_tables ses enclosure scsi_transport_sas i2c_opal ipmi_powernv ipmi_devintf i2c_core ipmi_msghandler powernv_op_panel nfsd auth_rpcgss oid_registry nfs_acl lockd grace sunrpc kvm_hv kvm_pr kvm scsi_dh_alua dm_service_time dm_multipath tg3 ptp pps_core [last unloaded: stap_552b612747aec2da355051e464fa72a1_14259]
[91652.629566] CPU: 136 PID: 41315 Comm: CPU 21/KVM Tainted: G O 4.14.0-1.rc4.dev.gitb27fc5c.el7.centos.ppc64le #1
[91652.629684] task: c0000007a419e400 task.stack: c0000000028d8000
[91652.629750] NIP: c0000000000e2640 LR: d00000000c36e498 CTR: c0000000000e25f0
[91652.629829] REGS: c0000000028db5d0 TRAP: 0300 Tainted: G O (4.14.0-1.rc4.dev.gitb27fc5c.el7.centos.ppc64le)
[91652.629932] MSR: 900000010280b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE,TM[E]> CR: 44022422 XER: 00000000
[91652.630034] CFAR: d00000000c373f84 DAR: d0000000157fb10c DSISR: 40000000 SOFTE: 1
[91652.630034] GPR00: d00000000c36e498 c0000000028db850 c000000001403900 c0000007b7960000
[91652.630034] GPR04: d0000000117fb100 d000000007ab00d8 000000000033bb10 0000000000000000
[91652.630034] GPR08: fffffffffffffe7f 801001810073bb10 d00000000e440000 d00000000c373f70
[91652.630034] GPR12: c0000000000e25f0 c00000000fdb9400 f000000003b24680 0000000000000000
[91652.630034] GPR16: 00000000000004fb 00007ff7081a0000 00000000000ec91a 000000000033bb10
[91652.630034] GPR20: 0000000000010000 00000000001b1190 0000000000000001 0000000000010000
[91652.630034] GPR24: c0000007b7ab8038 d0000000117fb100 0000000ec91a1190 c000001e6a000000
[91652.630034] GPR28: 00000000033bb100 000000000073bb10 c0000007b7960000 d0000000157fb100
[91652.630735] NIP [c0000000000e2640] kvmppc_add_revmap_chain+0x50/0x120
[91652.630806] LR [d00000000c36e498] kvmppc_book3s_hv_page_fault+0xbb8/0xc40 [kvm_hv]
[91652.630884] Call Trace:
[91652.630913] [c0000000028db850] [c0000000028db8b0] 0xc0000000028db8b0 (unreliable)
[91652.630996] [c0000000028db8b0] [d00000000c36e498] kvmppc_book3s_hv_page_fault+0xbb8/0xc40 [kvm_hv]
[91652.631091] [c0000000028db9e0] [d00000000c36a078] kvmppc_vcpu_run_hv+0xdf8/0x1300 [kvm_hv]
[91652.631179] [c0000000028dbb30] [d00000000c2248c4] kvmppc_vcpu_run+0x34/0x50 [kvm]
[91652.631266] [c0000000028dbb50] [d00000000c220d54] kvm_arch_vcpu_ioctl_run+0x114/0x2a0 [kvm]
[91652.631351] [c0000000028dbbd0] [d00000000c2139d8] kvm_vcpu_ioctl+0x598/0x7a0 [kvm]
[91652.631433] [c0000000028dbd40] [c0000000003832e0] do_vfs_ioctl+0xd0/0x8c0
[91652.631501] [c0000000028dbde0] [c000000000383ba4] SyS_ioctl+0xd4/0x130
[91652.631569] [c0000000028dbe30] [c00000000000b8e0] system_call+0x58/0x6c
[91652.631635] Instruction dump:
[91652.631676] fba1ffe8 fbc1fff0 fbe1fff8 f8010010 f821ffa1 2fa70000 793d0020 e9432110
[91652.631814] 7bbf26e4 7c7e1b78 7feafa14 409e0094 <807f000c> 786326e4 7c6a1a14 93a40008
[91652.631959] ---[ end trace ac85ba6db72e5b2e ]---
To fix this, we tighten up the way that the hpte_setup_done flag is
checked to ensure that it does provide the guarantee that the resizing
code needs. In kvmppc_run_core(), we check the hpte_setup_done flag
after disabling interrupts and refuse to enter the guest if it is
clear (for a HPT guest). The code that checks hpte_setup_done and
calls kvmppc_hv_setup_htab_rma() is moved from kvmppc_vcpu_run_hv()
to a point inside the main loop in kvmppc_run_vcpu(), ensuring that
we don't just spin endlessly calling kvmppc_run_core() while
hpte_setup_done is clear, but instead have a chance to block on the
kvm->lock mutex.
Finally we also check hpte_setup_done inside the region in
kvmppc_book3s_hv_page_fault() where the HPTE is locked and we are about
to update the HPTE, and bail out if it is clear. If another CPU is
inside kvm_vm_ioctl_resize_hpt_commit) and has cleared hpte_setup_done,
then we know that either we are looking at a HPTE
that resize_hpt_rehash_hpte() has not yet processed, which is OK,
or else we will see hpte_setup_done clear and refuse to update it,
because of the full barrier formed by the unlock of the HPTE in
resize_hpt_rehash_hpte() combined with the locking of the HPTE
in kvmppc_book3s_hv_page_fault().
Fixes: 5e9859699a ("KVM: PPC: Book3S HV: Outline of KVM-HV HPT resizing implementation")
Cc: stable@vger.kernel.org # v4.10+
Reported-by: Satheesh Rajendran <satheera@in.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
