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2024-10-25KVM: LoongArch: Use kvm_faultin_pfn() to map pfns into the guestSean Christopherson
Convert LoongArch to kvm_faultin_pfn()+kvm_release_faultin_page(), which are new APIs to consolidate arch code and provide consistent behavior across all KVM architectures. Signed-off-by: Sean Christopherson <seanjc@google.com> Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20241010182427.1434605-69-seanjc@google.com>
2024-10-25KVM: LoongArch: Mark "struct page" pfn accessed before dropping mmu_lockSean Christopherson
Mark pages accessed before dropping mmu_lock when faulting in guest memory so that LoongArch can convert to kvm_release_faultin_page() without tripping its lockdep assertion on mmu_lock being held. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Sean Christopherson <seanjc@google.com> Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20241010182427.1434605-68-seanjc@google.com>
2024-10-25KVM: LoongArch: Mark "struct page" pfns accessed only in "slow" page fault pathSean Christopherson
Mark pages accessed only in the slow path, before dropping mmu_lock when faulting in guest memory so that LoongArch can convert to kvm_release_faultin_page() without tripping its lockdep assertion on mmu_lock being held. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Sean Christopherson <seanjc@google.com> Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20241010182427.1434605-67-seanjc@google.com>
2024-10-25KVM: LoongArch: Mark "struct page" pfns dirty only in "slow" page fault pathSean Christopherson
Mark pages/folios dirty only the slow page fault path, i.e. only when mmu_lock is held and the operation is mmu_notifier-protected, as marking a page/folio dirty after it has been written back can make some filesystems unhappy (backing KVM guests will such filesystem files is uncommon, and the race is minuscule, hence the lack of complaints). See the link below for details. Link: https://lore.kernel.org/all/cover.1683044162.git.lstoakes@gmail.com Reviewed-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Sean Christopherson <seanjc@google.com> Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20241010182427.1434605-66-seanjc@google.com>
2024-08-07LoongArch: Use accessors to page table entries instead of direct dereferenceHuacai Chen
As very well explained in commit 20a004e7b017cce282 ("arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables"), an architecture whose page table walker can modify the PTE in parallel must use READ_ONCE()/ WRITE_ONCE() macro to avoid any compiler transformation. So apply that to LoongArch which is such an architecture, in order to avoid potential problems. Similar to commit edf955647269422e ("riscv: Use accessors to page table entries instead of direct dereference"). Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-07-09LoongArch: KVM: always make pte young in page map's fast pathJia Qingtong
It seems redundant to check if pte is young before the call to kvm_pte_mkyoung() in kvm_map_page_fast(). Just remove the check. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Jia Qingtong <jiaqingtong97@gmail.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-07-09LoongArch: KVM: Mark page accessed and dirty with page ref addedBibo Mao
Function kvm_map_page_fast() is fast path of secondary mmu page fault flow, pfn is parsed from secondary mmu page table walker. However the corresponding page reference is not added, it is dangerious to access page out of mmu_lock. Here page ref is added inside mmu_lock, function kvm_set_pfn_accessed() and kvm_set_pfn_dirty() is called with page ref added, so that the page will not be freed by others. Also kvm_set_pfn_accessed() is removed here since it is called in the following function kvm_release_pfn_clean(). Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-07-09LoongArch: KVM: Add dirty bitmap initially all set supportBibo Mao
Add KVM_DIRTY_LOG_INITIALLY_SET support on LoongArch system, this feature comes from other architectures like x86 and arm64. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-07-09LoongArch: KVM: Add memory barrier before update pmd entryBibo Mao
When updating pmd entry such as allocating new pmd page or splitting huge page into normal page, it is necessary to firstly update all pte entries, and then update pmd entry. It is weak order with LoongArch system, there will be problem if other VCPUs see pmd update firstly while ptes are not updated. Here smp_wmb() is added to assure this. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-07-09LoongArch: KVM: Discard dirty page tracking on readonly memslotBibo Mao
For readonly memslot such as UEFI BIOS or UEFI var space, guest cannot write this memory space directly. So it is not necessary to track dirty pages for readonly memslot. Here we make such optimization in function kvm_arch_commit_memory_region(). Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-07-09LoongArch: KVM: Select huge page only if secondary mmu supports itBibo Mao
Currently page level selection about secondary mmu depends on memory slot and page level about host mmu. There will be problems if page level of secondary mmu is zero already. Huge page cannot be selected if there is normal page mapped in secondary mmu already, since it is not supported to merge normal pages into huge pages now. So page level selection should depend on the following three conditions. 1. Memslot is aligned for huge page and vm is not migrating. 2. Page level of host mmu is also huge page. 3. Page level of secondary mmu is suituable for huge page. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-07-09LoongArch: KVM: Delay secondary mmu tlb flush until guest entryBibo Mao
With hardware assisted virtualization, there are two level HW mmu, one is GVA to GPA mapping, the other is GPA to HPA mapping which is called secondary mmu in generic. If there is page fault for secondary mmu, there needs tlb flush operation indexed with fault GPA address and VMID. VMID is stored at register CSR.GSTAT and will be reload or recalculated before guest entry. Currently CSR.GSTAT is not saved and restored during VCPU context switch, instead it is recalculated during guest entry. So CSR.GSTAT is effective only when a VCPU runs in guest mode, however it may not be effective if the VCPU exits to host mode. Since register CSR.GSTAT may be stale, it may records the VMID of the last schedule-out VCPU, rather than the current VCPU. Function kvm_flush_tlb_gpa() should be called with its real VMID, so here move it to the guest entrance. Also an arch-specific request id KVM_REQ_TLB_FLUSH_GPA is added to flush tlb for secondary mmu, and it can be optimized if VMID is updated, since all guest tlb entries will be invalid if VMID is updated. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-04-11KVM: delete .change_pte MMU notifier callbackPaolo Bonzini
The .change_pte() MMU notifier callback was intended as an optimization. The original point of it was that KSM could tell KVM to flip its secondary PTE to a new location without having to first zap it. At the time there was also an .invalidate_page() callback; both of them were *not* bracketed by calls to mmu_notifier_invalidate_range_{start,end}(), and .invalidate_page() also doubled as a fallback implementation of .change_pte(). Later on, however, both callbacks were changed to occur within an invalidate_range_start/end() block. In the case of .change_pte(), commit 6bdb913f0a70 ("mm: wrap calls to set_pte_at_notify with invalidate_range_start and invalidate_range_end", 2012-10-09) did so to remove the fallback from .invalidate_page() to .change_pte() and allow sleepable .invalidate_page() hooks. This however made KVM's usage of the .change_pte() callback completely moot, because KVM unmaps the sPTEs during .invalidate_range_start() and therefore .change_pte() has no hope of finding a sPTE to change. Drop the generic KVM code that dispatches to kvm_set_spte_gfn(), as well as all the architecture specific implementations. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Anup Patel <anup@brainfault.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Reviewed-by: Bibo Mao <maobibo@loongson.cn> Message-ID: <20240405115815.3226315-2-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-03-06mm/treewide: drop pXd_large()Peter Xu
They're not used anymore, drop all of them. Link: https://lkml.kernel.org/r/20240305043750.93762-10-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Muchun Song <muchun.song@linux.dev> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-01-26LoongArch: KVM: Fix build due to API changesHuacai Chen
Commit 8569992d64b8f750e34b7858eac ("KVM: Use gfn instead of hva for mmu_notifier_retry") replaces mmu_invalidate_retry_hva() usage with mmu_invalidate_retry_gfn() for X86, LoongArch also need similar changes to fix build. Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-12-19LoongArch: KVM: Optimization for memslot hugepage checkingBibo Mao
During shadow mmu page fault, there is checking for huge page for specified memslot. Page fault is hot path, check logic can be done when memslot is created. Here two flags are added for huge page checking, KVM_MEM_HUGEPAGE_CAPABLE and KVM_MEM_HUGEPAGE_INCAPABLE. Indeed for an optimized qemu, memslot for DRAM is always huge page aligned. The flag is firstly checked during hot page fault path. Now only huge page flag is supported, there is a long way for super page support in LoongArch system. Since super page size is 64G for 16K pagesize and 1G for 4K pagesize, 64G physical address is rarely used and LoongArch kernel needs support super page for 4K. Also memory layout of LoongArch qemu VM should be 1G aligned. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-10-02LoongArch: KVM: Implement kvm mmu operationsTianrui Zhao
Implement LoongArch kvm mmu, it is used to switch gpa to hpa when guest exit because of address translation exception. This patch implement: allocating gpa page table, searching gpa from it, and flushing guest gpa in the table. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Tested-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>