linux/virt/kvm
Jia He 47a91b7232 KVM: arm/arm64: add WARN_ON if size is not PAGE_SIZE aligned in unmap_stage2_range
There is a panic in armv8a server(QDF2400) under memory pressure tests
(start 20 guests and run memhog in the host).

---------------------------------begin--------------------------------
[35380.800950] BUG: Bad page state in process qemu-kvm  pfn:dd0b6
[35380.805825] page:ffff7fe003742d80 count:-4871 mapcount:-2126053375
mapping:          (null) index:0x0
[35380.815024] flags: 0x1fffc00000000000()
[35380.818845] raw: 1fffc00000000000 0000000000000000 0000000000000000
ffffecf981470000
[35380.826569] raw: dead000000000100 dead000000000200 ffff8017c001c000
0000000000000000
[35380.805825] page:ffff7fe003742d80 count:-4871 mapcount:-2126053375
mapping:          (null) index:0x0
[35380.815024] flags: 0x1fffc00000000000()
[35380.818845] raw: 1fffc00000000000 0000000000000000 0000000000000000
ffffecf981470000
[35380.826569] raw: dead000000000100 dead000000000200 ffff8017c001c000
0000000000000000
[35380.834294] page dumped because: nonzero _refcount
[...]
--------------------------------end--------------------------------------

The root cause might be what was fixed at [1]. But from the KVM points of
view, it would be better if the issue was caught earlier.

If the size is not PAGE_SIZE aligned, unmap_stage2_range might unmap the
wrong(more or less) page range. Hence it caused the "BUG: Bad page
state"

Let's WARN in that case, so that the issue is obvious.

[1] https://lkml.org/lkml/2018/5/3/1042

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: jia.he@hxt-semitech.com
[maz: tidied up commit message]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-06-21 11:48:03 +01:00
..
arm KVM: arm/arm64: add WARN_ON if size is not PAGE_SIZE aligned in unmap_stage2_range 2018-06-21 11:48:03 +01:00
async_pf.c kvm,async_pf: Use swq_has_sleeper() 2017-09-15 16:57:11 +02:00
async_pf.h KVM: fix checkpatch.pl errors in kvm/async_pf.h 2015-06-19 17:16:25 +02:00
coalesced_mmio.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
coalesced_mmio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
eventfd.c fs: add new vfs_poll and file_can_poll helpers 2018-05-26 09:16:44 +02:00
irqchip.c KVM: use rcu access function for irq routing 2017-07-07 15:24:15 +02:00
Kconfig KVM: arm/arm64: Introduce kvm_arch_vcpu_run_pid_change 2018-05-25 12:27:54 +01:00
kvm_main.c - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
vfio.c vfio: New external user group/file match 2017-06-28 13:50:05 -06:00
vfio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00