[v13,57/85] KVM: RISC-V: Mark "struct page" pfns dirty iff a stage-2 PTE is installed

Commit Message

Sean Christopherson Oct. 10, 2024, 6:23 p.m. UTC

Don't mark pages dirty if KVM bails from the page fault handler without
installing a stage-2 mapping, i.e. if the page is guaranteed to not be
written by the guest.

In addition to being a (very) minor fix, this paves the way for converting
RISC-V to use kvm_release_faultin_page().

Reviewed-by: Andrew Jones <[e-mail]>
Acked-by: Anup Patel <[e-mail]>
Signed-off-by: Sean Christopherson <[e-mail]>
---
 arch/riscv/kvm/mmu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Patch

diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index b63650f9b966..06aa5a0d056d 100644
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -669,7 +669,6 @@  int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
 		goto out_unlock;
 
 	if (writable) {
-		kvm_set_pfn_dirty(hfn);
 		mark_page_dirty(kvm, gfn);
 		ret = gstage_map_page(kvm, pcache, gpa, hfn << PAGE_SHIFT,
 				      vma_pagesize, false, true);
@@ -682,6 +681,9 @@  int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
 		kvm_err("Failed to map in G-stage\n");
 
 out_unlock:
+	if ((!ret || ret == -EEXIST) && writable)
+		kvm_set_pfn_dirty(hfn);
+
 	spin_unlock(&kvm->mmu_lock);
 	kvm_set_pfn_accessed(hfn);
 	kvm_release_pfn_clean(hfn);