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This can be used in two modes. There is an atomic mode where the cached mapping is accessed while holding the rwlock, and a mode where the physical address is used by a vCPU in guest mode. For the latter case, an invalidation will wake the vCPU with the new KVM_REQ_GPC_INVALIDATE, and the architecture will need to refresh any caches it still needs to access before entering guest mode again. Only one vCPU can be targeted by the wake requests; it's simple enough to make it wake all vCPUs or even a mask but I don't see a use case for that additional complexity right now. Invalidation happens from the invalidate_range_start MMU notifier, which needs to be able to sleep in order to wake the vCPU and wait for it. This means that revalidation potentially needs to "wait" for the MMU operation to complete and the invalidate_range_end notifier to be invoked. Like the vCPU when it takes a page fault in that period, we just spin — fixing that in a future patch by implementing an actual *wait* may be another part of shaving this particularly hirsute yak. As noted in the comments in the function itself, the only case where the invalidate_range_start notifier is expected to be called *without* being able to sleep is when the OOM reaper is killing the process. In that case, we expect the vCPU threads already to have exited, and thus there will be nothing to wake, and no reason to wait. So we clear the KVM_REQUEST_WAIT bit and send the request anyway, then complain loudly if there actually *was* anything to wake up. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20211210163625.2886-3-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
74 lines
1.1 KiB
Text
74 lines
1.1 KiB
Text
# SPDX-License-Identifier: GPL-2.0
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# KVM common configuration items and defaults
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config HAVE_KVM
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bool
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config HAVE_KVM_PFNCACHE
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bool
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config HAVE_KVM_IRQCHIP
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bool
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config HAVE_KVM_IRQFD
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bool
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config HAVE_KVM_IRQ_ROUTING
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bool
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config HAVE_KVM_DIRTY_RING
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bool
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config HAVE_KVM_EVENTFD
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bool
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select EVENTFD
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config KVM_MMIO
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bool
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config KVM_ASYNC_PF
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bool
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# Toggle to switch between direct notification and batch job
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config KVM_ASYNC_PF_SYNC
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bool
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config HAVE_KVM_MSI
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bool
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config HAVE_KVM_CPU_RELAX_INTERCEPT
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bool
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config KVM_VFIO
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bool
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config HAVE_KVM_ARCH_TLB_FLUSH_ALL
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bool
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config HAVE_KVM_INVALID_WAKEUPS
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bool
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config KVM_GENERIC_DIRTYLOG_READ_PROTECT
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bool
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config KVM_COMPAT
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def_bool y
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depends on KVM && COMPAT && !(S390 || ARM64)
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config HAVE_KVM_IRQ_BYPASS
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bool
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config HAVE_KVM_VCPU_ASYNC_IOCTL
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bool
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config HAVE_KVM_VCPU_RUN_PID_CHANGE
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bool
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config HAVE_KVM_NO_POLL
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bool
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config KVM_XFER_TO_GUEST_WORK
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bool
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config HAVE_KVM_PM_NOTIFIER
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bool
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