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2ebbe0308c
Add a Kconfig to allow architectures to opt-out of a TLB flush when a young page is aged, as invalidating TLB entries is not functionally required on most KVM-supported architectures. Stale TLB entries can result in false negatives and theoretically lead to suboptimal reclaim, but in practice all observations have been that the performance gained by skipping TLB flushes outweighs any performance lost by reclaiming hot pages. E.g. the primary MMUs for x86 RISC-V, s390, and PPC Book3S elide the TLB flush for ptep_clear_flush_young(), and arm64's MMU skips the trailing DSB that's required for ordering (presumably because there are optimizations related to eliding other TLB flushes when doing make-before-break). Link: https://lore.kernel.org/r/20241011021051.1557902-18-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
127 lines
2.5 KiB
Plaintext
127 lines
2.5 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0
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# KVM common configuration items and defaults
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config KVM_COMMON
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bool
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select EVENTFD
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select INTERVAL_TREE
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select PREEMPT_NOTIFIERS
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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_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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# Only strongly ordered architectures can select this, as it doesn't
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# put any explicit constraint on userspace ordering. They can also
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# select the _ACQ_REL version.
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config HAVE_KVM_DIRTY_RING_TSO
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bool
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select HAVE_KVM_DIRTY_RING
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depends on X86
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# Weakly ordered architectures can only select this, advertising
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# to userspace the additional ordering requirements.
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config HAVE_KVM_DIRTY_RING_ACQ_REL
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bool
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select HAVE_KVM_DIRTY_RING
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# Allow enabling both the dirty bitmap and dirty ring. Only architectures
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# that need to dirty memory outside of a vCPU context should select this.
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config NEED_KVM_DIRTY_RING_WITH_BITMAP
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bool
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depends on HAVE_KVM_DIRTY_RING
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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_READONLY_MEM
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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_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_GENERIC_PRE_FAULT_MEMORY
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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 || RISCV)
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config HAVE_KVM_IRQ_BYPASS
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bool
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select IRQ_BYPASS_MANAGER
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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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config KVM_GENERIC_HARDWARE_ENABLING
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bool
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config KVM_GENERIC_MMU_NOTIFIER
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select MMU_NOTIFIER
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bool
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config KVM_ELIDE_TLB_FLUSH_IF_YOUNG
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depends on KVM_GENERIC_MMU_NOTIFIER
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bool
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config KVM_GENERIC_MEMORY_ATTRIBUTES
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depends on KVM_GENERIC_MMU_NOTIFIER
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bool
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config KVM_PRIVATE_MEM
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select XARRAY_MULTI
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bool
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config KVM_GENERIC_PRIVATE_MEM
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select KVM_GENERIC_MEMORY_ATTRIBUTES
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select KVM_PRIVATE_MEM
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bool
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config HAVE_KVM_ARCH_GMEM_PREPARE
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bool
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depends on KVM_PRIVATE_MEM
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config HAVE_KVM_ARCH_GMEM_INVALIDATE
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bool
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depends on KVM_PRIVATE_MEM
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