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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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411740f542
Implement the SYNC_MMU capability for KVM MIPS, allowing changes in the underlying user host virtual address (HVA) mappings to be promptly reflected in the corresponding guest physical address (GPA) mappings. This allows for several features to work with guest RAM which require mappings to be altered or protected, such as copy-on-write, KSM (Kernel Samepage Merging), idle page tracking, memory swapping, and guest memory ballooning. There are two main aspects of this change, described below. The KVM MMU notifier architecture callbacks are implemented so we can be notified of changes in the HVA mappings. These arrange for the guest physical address (GPA) page tables to be modified and possibly for derived mappings (GVA page tables and TLBs) to be flushed. - kvm_unmap_hva[_range]() - These deal with HVA mappings being removed, for example before a copy-on-write takes place, which requires the corresponding GPA page table mappings to be removed too. - kvm_set_spte_hva() - These update a GPA page table entry to match the new HVA entry, but must be careful to respect KVM specific configuration such as not dirtying a clean guest page which is dirty to the host, and write protecting writable pages in read only memslots (which will soon be supported). - kvm[_test]_age_hva() - These update GPA page table entries to be old (invalid) so that access can be tracked, making them young again. The GPA page fault handling (kvm_mips_map_page) is updated to use gfn_to_pfn_prot() (which may provide read-only pages), to handle asynchronous page table invalidation from MMU notifier callbacks, and to handle more cases in the fast path. - mmu_notifier_seq is used to detect asynchronous page table invalidations while we're holding a pfn from gfn_to_pfn_prot() outside of kvm->mmu_lock, retrying if invalidations have taken place, e.g. a COW or a KSM page merge. - The fast path (_kvm_mips_map_page_fast) now handles marking old pages as young / accessed, and disallowing dirtying of clean pages that aren't actually writable (e.g. shared pages that should COW, and read-only memory regions when they are enabled in a future patch). - Due to the use of MMU notifications we no longer need to keep the page references after we've updated the GPA page tables. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
53 lines
1.2 KiB
Plaintext
53 lines
1.2 KiB
Plaintext
#
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# KVM configuration
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#
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source "virt/kvm/Kconfig"
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menuconfig VIRTUALIZATION
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bool "Virtualization"
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---help---
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Say Y here to get to see options for using your Linux host to run
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other operating systems inside virtual machines (guests).
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This option alone does not add any kernel code.
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If you say N, all options in this submenu will be skipped and disabled.
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if VIRTUALIZATION
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config KVM
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tristate "Kernel-based Virtual Machine (KVM) support"
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depends on HAVE_KVM
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select EXPORT_UASM
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select PREEMPT_NOTIFIERS
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select ANON_INODES
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select KVM_GENERIC_DIRTYLOG_READ_PROTECT
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select KVM_MMIO
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select MMU_NOTIFIER
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select SRCU
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---help---
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Support for hosting Guest kernels.
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Currently supported on MIPS32 processors.
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config KVM_MIPS_DYN_TRANS
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bool "KVM/MIPS: Dynamic binary translation to reduce traps"
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depends on KVM
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---help---
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When running in Trap & Emulate mode patch privileged
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instructions to reduce the number of traps.
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If unsure, say Y.
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config KVM_MIPS_DEBUG_COP0_COUNTERS
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bool "Maintain counters for COP0 accesses"
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depends on KVM
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---help---
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Maintain statistics for Guest COP0 accesses.
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A histogram of COP0 accesses is printed when the VM is
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shutdown.
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If unsure, say N.
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source drivers/vhost/Kconfig
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endif # VIRTUALIZATION
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