KVM: RISC-V: Mark "struct page" pfns accessed before dropping mmu_lock

Mark pages accessed before dropping mmu_lock when faulting in guest memory
so that RISC-V can convert to kvm_release_faultin_page() without tripping
its lockdep assertion on mmu_lock being held.  Marking pages accessed
outside of mmu_lock is ok (not great, but safe), but marking pages _dirty_
outside of mmu_lock can make filesystems unhappy (see the link below).
Do both under mmu_lock to minimize the chances of doing the wrong thing in
the future.

Link: https://lore.kernel.org/all/cover.1683044162.git.lstoakes@gmail.com
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Acked-by: Anup Patel <anup@brainfault.org>
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: <20241010182427.1434605-59-seanjc@google.com>

diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index 06aa5a0d056d47fbbd5f6bcf1c626488b7f78fd9..2e9aee51814273fb5b9cc7db5eef2b15f60cb220 100644 (file)
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -682,11 +682,11 @@ int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
 
 out_unlock:
        if ((!ret || ret == -EEXIST) && writable)
-               kvm_set_pfn_dirty(hfn);
+               kvm_release_pfn_dirty(hfn);
+       else
+               kvm_release_pfn_clean(hfn);
 
        spin_unlock(&kvm->mmu_lock);
-       kvm_set_pfn_accessed(hfn);
-       kvm_release_pfn_clean(hfn);
        return ret;
 }