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KVM: PPC: Book3S: Mark "struct page" pfns dirty/accessed after installing PTE

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Mark pages/folios dirty/accessed after installing a PTE, and more
specifically after acquiring mmu_lock and checking for an mmu_notifier
invalidation.  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.

This will also allow converting Book3S to kvm_release_faultin_page(),
which requires that mmu_lock be held (for the aforementioned reason).

Link: https://lore.kernel.org/all/cover.1683044162.git.lstoakes@gmail.com
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: <20241010182427.1434605-64-seanjc@google.com>
This commit is contained in:
Sean Christopherson
2024-10-25 13:00:49 -04:00
committed by Paolo Bonzini
parent dac09f61e7
commit 2b26d6b7a8
1 changed files with 5 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/powerpc/kvm/book3s_64_mmu_host.c
+5 -5
View File
@@ -121,13 +121,10 @@ int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte,
vpn = hpt_vpn(orig_pte->eaddr, map->host_vsid, MMU_SEGSIZE_256M);
kvm_set_pfn_accessed(pfn);
if (!orig_pte->may_write || !writable)
rflags |= PP_RXRX;
else {
else
mark_page_dirty(vcpu->kvm, gfn);
kvm_set_pfn_dirty(pfn);
}
if (!orig_pte->may_execute)
rflags |= HPTE_R_N;
@@ -202,8 +199,11 @@ map_again:
}
out_unlock:
if (!orig_pte->may_write || !writable)
kvm_release_pfn_clean(pfn);
else
kvm_release_pfn_dirty(pfn);
spin_unlock(&kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
if (cpte)
kvmppc_mmu_hpte_cache_free(cpte);