Sean Christopherson 32b758d12c KVM: s390: Ensure kvm_arch_no_poll() is read once when blocking vCPU ... [ Upstream commit 6f390916c4 ] Wrap s390's halt_poll_max_steal with READ_ONCE and snapshot the result of kvm_arch_no_poll() in kvm_vcpu_block() to avoid a mostly-theoretical, largely benign bug on s390 where the result of kvm_arch_no_poll() could change due to userspace modifying halt_poll_max_steal while the vCPU is blocking. The bug is largely benign as it will either cause KVM to skip updating halt-polling times (no_poll toggles false=>true) or to update halt-polling times with a slightly flawed block_ns. Note, READ_ONCE is unnecessary in the current code, add it in case the arch hook is ever inlined, and to provide a hint that userspace can change the param at will. Fixes: 8b905d28ee ("KVM: s390: provide kvm_arch_no_poll function") Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211009021236.4122790-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		2022-03-08 19:12:34 +01:00
..
async_pf.c	mm/gup: remove task_struct pointer for all gup code	2020-08-12 10:58:04 -07:00
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	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
dirty_ring.c	KVM: Drop unused kvm_dirty_gfn_invalid()	2021-09-06 08:23:46 -04:00
eventfd.c	KVM: eventfd: Fix false positive RCU usage warning	2022-02-16 12:56:16 +01:00
irqchip.c	KVM/arm updates for 5.3	2019-07-11 15:14:16 +02:00
Kconfig	kvm: add PM-notifier	2021-06-17 13:09:32 -04:00
kvm_main.c	KVM: s390: Ensure kvm_arch_no_poll() is read once when blocking vCPU	2022-03-08 19:12:34 +01:00
mmu_lock.h	KVM: x86/mmu: Use an rwlock for the x86 MMU	2021-02-04 05:27:43 -05:00
vfio.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
vfio.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00