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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Paul Mackerras <paulus@ozlabs.org>
Subject: [PATCH 4.14 18/62] KVM: PPC: Book3S HV: Fix trap number return from __kvmppc_vcore_entry
Date: Mon, 14 May 2018 08:48:34 +0200	[thread overview]
Message-ID: <20180514064817.413157098@linuxfoundation.org> (raw)
In-Reply-To: <20180514064816.436958006@linuxfoundation.org>

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Paul Mackerras <paulus@ozlabs.org>

commit a8b48a4dccea77e29462e59f1dbf0d5aa1ff167c upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/powerpc/kvm/book3s_hv_rmhandlers.S |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -308,7 +308,6 @@ kvm_novcpu_exit:
 	stw	r12, STACK_SLOT_TRAP(r1)
 	bl	kvmhv_commence_exit
 	nop
-	lwz	r12, STACK_SLOT_TRAP(r1)
 	b	kvmhv_switch_to_host
 
 /*
@@ -1136,6 +1135,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
 
 secondary_too_late:
 	li	r12, 0
+	stw	r12, STACK_SLOT_TRAP(r1)
 	cmpdi	r4, 0
 	beq	11f
 	stw	r12, VCPU_TRAP(r4)
@@ -1445,12 +1445,12 @@ mc_cont:
 1:
 #endif /* CONFIG_KVM_XICS */
 
+	stw	r12, STACK_SLOT_TRAP(r1)
 	mr 	r3, r12
 	/* Increment exit count, poke other threads to exit */
 	bl	kvmhv_commence_exit
 	nop
 	ld	r9, HSTATE_KVM_VCPU(r13)
-	lwz	r12, VCPU_TRAP(r9)
 
 	/* Stop others sending VCPU interrupts to this physical CPU */
 	li	r0, -1
@@ -1816,6 +1816,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_POWER9_DD1
 	 * POWER7/POWER8 guest -> host partition switch code.
 	 * We don't have to lock against tlbies but we do
 	 * have to coordinate the hardware threads.
+	 * Here STACK_SLOT_TRAP(r1) contains the trap number.
 	 */
 kvmhv_switch_to_host:
 	/* Secondary threads wait for primary to do partition switch */
@@ -1868,11 +1869,11 @@ BEGIN_FTR_SECTION
 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
 
 	/* If HMI, call kvmppc_realmode_hmi_handler() */
+	lwz	r12, STACK_SLOT_TRAP(r1)
 	cmpwi	r12, BOOK3S_INTERRUPT_HMI
 	bne	27f
 	bl	kvmppc_realmode_hmi_handler
 	nop
-	li	r12, BOOK3S_INTERRUPT_HMI
 	/*
 	 * At this point kvmppc_realmode_hmi_handler would have resync-ed
 	 * the TB. Hence it is not required to subtract guest timebase
@@ -1950,6 +1951,7 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_R
 	li	r0, KVM_GUEST_MODE_NONE
 	stb	r0, HSTATE_IN_GUEST(r13)
 
+	lwz	r12, STACK_SLOT_TRAP(r1)	/* return trap # in r12 */
 	ld	r0, SFS+PPC_LR_STKOFF(r1)
 	addi	r1, r1, SFS
 	mtlr	r0

  parent reply	other threads:[~2018-05-14  6:48 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-14  6:48 [PATCH 4.14 00/62] 4.14.41-stable review Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 01/62] ipvs: fix rtnl_lock lockups caused by start_sync_thread Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 02/62] netfilter: ebtables: dont attempt to allocate 0-sized compat array Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 03/62] kcm: Call strp_stop before strp_done in kcm_attach Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 04/62] crypto: af_alg - fix possible uninit-value in alg_bind() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 05/62] netlink: fix uninit-value in netlink_sendmsg Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 06/62] net: fix rtnh_ok() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 07/62] net: initialize skb->peeked when cloning Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 08/62] net: fix uninit-value in __hw_addr_add_ex() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 09/62] dccp: initialize ireq->ir_mark Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 10/62] ipv4: fix uninit-value in ip_route_output_key_hash_rcu() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 11/62] soreuseport: initialise timewait reuseport field Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 12/62] inetpeer: fix uninit-value in inet_getpeer Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 13/62] memcg: fix per_node_info cleanup Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 14/62] perf: Remove superfluous allocation error check Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 15/62] tcp: fix TCP_REPAIR_QUEUE bound checking Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 16/62] bdi: wake up concurrent wb_shutdown() callers Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 17/62] bdi: Fix oops in wb_workfn() Greg Kroah-Hartman
2018-05-14  6:48 ` Greg Kroah-Hartman [this message]
2018-05-14  6:48 ` [PATCH 4.14 19/62] KVM: PPC: Book3S HV: Fix guest time accounting with VIRT_CPU_ACCOUNTING_GEN Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 20/62] KVM: PPC: Book3S HV: Fix VRMA initialization with 2MB or 1GB memory backing Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 21/62] arm64: Add work around for Arm Cortex-A55 Erratum 1024718 Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 22/62] compat: fix 4-byte infoleak via uninitialized struct field Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 23/62] gpioib: do not free unrequested descriptors Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 24/62] gpio: fix aspeed_gpio unmask irq Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 25/62] gpio: fix error path in lineevent_create Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 26/62] rfkill: gpio: fix memory leak in probe error path Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 27/62] libata: Apply NOLPM quirk for SanDisk SD7UB3Q*G1001 SSDs Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 28/62] dm integrity: use kvfree for kvmallocd memory Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 29/62] tracing: Fix regex_match_front() to not over compare the test string Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 30/62] z3fold: fix reclaim lock-ups Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 31/62] mm: sections are not offlined during memory hotremove Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 32/62] mm, oom: fix concurrent munlock and oom reaper unmap, v3 Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 33/62] ceph: fix rsize/wsize capping in ceph_direct_read_write() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 34/62] can: kvaser_usb: Increase correct stats counter in kvaser_usb_rx_can_msg() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 35/62] can: hi311x: Acquire SPI lock on ->do_get_berr_counter Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 36/62] can: hi311x: Work around TX complete interrupt erratum Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 37/62] drm/vc4: Fix scaling of uni-planar formats Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 38/62] drm/i915: Fix drm:intel_enable_lvds ERROR message in kernel log Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 39/62] drm/nouveau: Fix deadlock in nv50_mstm_register_connector() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 40/62] drm/atomic: Clean old_state/new_state in drm_atomic_state_default_clear() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 41/62] drm/atomic: Clean private obj " Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 42/62] net: atm: Fix potential Spectre v1 Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 43/62] atm: zatm: " Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 44/62] PCI / PM: Always check PME wakeup capability for runtime wakeup support Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 45/62] PCI / PM: Check device_may_wakeup() in pci_enable_wake() Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 46/62] cpufreq: schedutil: Avoid using invalid next_freq Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 47/62] Revert "Bluetooth: btusb: Fix quirk for Atheros 1525/QCA6174" Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 48/62] Bluetooth: btusb: Add Dell XPS 13 9360 to btusb_needs_reset_resume_table Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 49/62] Bluetooth: btusb: Only check needs_reset_resume DMI table for QCA rome chipsets Greg Kroah-Hartman
2018-05-15 17:07   ` Brian Norris
2018-05-15 19:42     ` Guenter Roeck
2018-05-16  7:57       ` gregkh
2018-05-14  6:49 ` [PATCH 4.14 50/62] thermal: exynos: Reading temperature makes sense only when TMU is turned on Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 51/62] thermal: exynos: Propagate error value from tmu_read() Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 52/62] nvme: add quirk to force medium priority for SQ creation Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 53/62] smb3: directory sync should not return an error Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 54/62] sched/autogroup: Fix possible Spectre-v1 indexing for sched_prio_to_weight[] Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 55/62] tracing/uprobe_event: Fix strncpy corner case Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 56/62] perf/x86: Fix possible Spectre-v1 indexing for hw_perf_event cache_* Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 57/62] perf/x86/cstate: Fix possible Spectre-v1 indexing for pkg_msr Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 58/62] perf/x86/msr: Fix possible Spectre-v1 indexing in the MSR driver Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 59/62] perf/core: Fix possible Spectre-v1 indexing for ->aux_pages[] Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 60/62] perf/x86: Fix possible Spectre-v1 indexing for x86_pmu::event_map() Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 61/62] KVM: PPC: Book3S HV: Fix handling of large pages in radix page fault handler Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 62/62] KVM: x86: remove APIC Timer periodic/oneshot spikes Greg Kroah-Hartman
2018-05-14  8:28 ` [PATCH 4.14 00/62] 4.14.41-stable review Nathan Chancellor
2018-05-14 12:45 ` kernelci.org bot
2018-05-14 16:21 ` Guenter Roeck
2018-05-14 22:02 ` Shuah Khan
2018-05-15  5:36 ` Naresh Kamboju

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