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52491a38b2
linux/virt/kvm
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Michal Luczaj 52491a38b2 KVM: Initialize gfn_to_pfn_cache locks in dedicated helper 
Move the gfn_to_pfn_cache lock initialization to another helper and
call the new helper during VM/vCPU creation.  There are race
conditions possible due to kvm_gfn_to_pfn_cache_init()'s
ability to re-initialize the cache's locks.

For example: a race between ioctl(KVM_XEN_HVM_EVTCHN_SEND) and
kvm_gfn_to_pfn_cache_init() leads to a corrupted shinfo gpc lock.

                (thread 1)                |           (thread 2)
                                          |
 kvm_xen_set_evtchn_fast                  |
  read_lock_irqsave(&gpc->lock, ...)      |
                                          | kvm_gfn_to_pfn_cache_init
                                          |  rwlock_init(&gpc->lock)
  read_unlock_irqrestore(&gpc->lock, ...) |

Rename "cache_init" and "cache_destroy" to activate+deactivate to
avoid implying that the cache really is destroyed/freed.

Note, there more races in the newly named kvm_gpc_activate() that will
be addressed separately.

Fixes: 982ed0de47 ("KVM: Reinstate gfn_to_pfn_cache with invalidation support")
Cc: stable@vger.kernel.org
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
[sean: call out that this is a bug fix]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221013211234.1318131-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-10-27 06:47:53 -04:00
..
async_pf.c KVM: Add helpers to wake/query blocking vCPU 2021-12-08 04:24:54 -05:00
async_pf.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504 2019-06-19 17:09:56 +02:00
binary_stats.c KVM: stats: remove dead stores 2021-08-13 03:35:15 -04:00
coalesced_mmio.c KVM: mmio: Fix use-after-free Read in kvm_vm_ioctl_unregister_coalesced_mmio 2021-07-14 12:17:56 -04:00
coalesced_mmio.h
dirty_ring.c KVM: Use acquire/release semantics when accessing dirty ring GFN state 2022-09-29 10:23:08 +01:00
eventfd.c KVM: eventfd: Fix false positive RCU usage warning 2022-05-20 09:10:33 -04:00
irqchip.c KVM/arm updates for 5.3 2019-07-11 15:14:16 +02:00
Kconfig KVM: Add KVM_CAP_DIRTY_LOG_RING_ACQ_REL capability and config option 2022-09-29 10:23:08 +01:00
kvm_main.c KVM: debugfs: Return retval of simple_attr_open() if it fails 2022-10-27 04:41:55 -04:00
kvm_mm.h KVM: SPDX style and spelling fixes 2022-04-21 13:16:13 -04:00
Makefile.kvm KVM: Reinstate gfn_to_pfn_cache with invalidation support 2022-01-07 10:44:44 -05:00
pfncache.c KVM: Initialize gfn_to_pfn_cache locks in dedicated helper 2022-10-27 06:47:53 -04:00
vfio.c vfio: Hold a reference to the iommu_group in kvm for SPAPR 2022-10-07 08:10:52 -06:00
vfio.h