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-rw-r--r--arch/riscv/kvm/mmu.c25
1 files changed, 16 insertions, 9 deletions
diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index 78211aed36fa..46d692995830 100644
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -628,6 +628,13 @@ int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
!(memslot->flags & KVM_MEM_READONLY)) ? true : false;
unsigned long vma_pagesize, mmu_seq;
+ /* We need minimum second+third level pages */
+ ret = kvm_mmu_topup_memory_cache(pcache, gstage_pgd_levels);
+ if (ret) {
+ kvm_err("Failed to topup G-stage cache\n");
+ return ret;
+ }
+
mmap_read_lock(current->mm);
vma = vma_lookup(current->mm, hva);
@@ -648,6 +655,15 @@ int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
gfn = (gpa & huge_page_mask(hstate_vma(vma))) >> PAGE_SHIFT;
+ /*
+ * Read mmu_invalidate_seq so that KVM can detect if the results of
+ * vma_lookup() or gfn_to_pfn_prot() become stale priort to acquiring
+ * kvm->mmu_lock.
+ *
+ * Rely on mmap_read_unlock() for an implicit smp_rmb(), which pairs
+ * with the smp_wmb() in kvm_mmu_invalidate_end().
+ */
+ mmu_seq = kvm->mmu_invalidate_seq;
mmap_read_unlock(current->mm);
if (vma_pagesize != PUD_SIZE &&
@@ -657,15 +673,6 @@ int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
return -EFAULT;
}
- /* We need minimum second+third level pages */
- ret = kvm_mmu_topup_memory_cache(pcache, gstage_pgd_levels);
- if (ret) {
- kvm_err("Failed to topup G-stage cache\n");
- return ret;
- }
-
- mmu_seq = kvm->mmu_invalidate_seq;
-
hfn = gfn_to_pfn_prot(kvm, gfn, is_write, &writable);
if (hfn == KVM_PFN_ERR_HWPOISON) {
send_sig_mceerr(BUS_MCEERR_AR, (void __user *)hva,