Convert user_mem_abort() to call kvm_pgtable_stage2_relax_perms() when
handling a stage-2 permission fault and kvm_pgtable_stage2_map() when
handling a stage-2 translation fault, rather than walking the page-table
manually.
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Quentin Perret <qperret@xxxxxxxxxx>
Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>
Reviewed-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
---
arch/arm64/kvm/mmu.c | 124 +++++++++++++++----------------------------
1 file changed, 44 insertions(+), 80 deletions(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index d5813996c0e4..e980e614dd81 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1499,18 +1499,19 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
{
int ret;
bool write_fault, writable, force_pte = false;
- bool exec_fault, needs_exec;
+ bool exec_fault;
+ bool device = false;
unsigned long mmu_seq;
- gfn_t gfn = fault_ipa >> PAGE_SHIFT;
struct kvm *kvm = vcpu->kvm;
struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
struct vm_area_struct *vma;
short vma_shift;
+ gfn_t gfn;
kvm_pfn_t pfn;
- pgprot_t mem_type = PAGE_S2;
bool logging_active = memslot_is_logging(memslot);
- unsigned long vma_pagesize, flags = 0;
- struct kvm_s2_mmu *mmu = vcpu->arch.hw_mmu;
+ unsigned long vma_pagesize;
+ enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
+ struct kvm_pgtable *pgt;
write_fault = kvm_is_write_fault(vcpu);
exec_fault = kvm_vcpu_trap_is_iabt(vcpu);
@@ -1543,22 +1544,24 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
vma_pagesize = PAGE_SIZE;
}
- /*
- * The stage2 has a minimum of 2 level table (For arm64 see
- * kvm_arm_setup_stage2()). Hence, we are guaranteed that we can
- * use PMD_SIZE huge mappings (even when the PMD is folded into PGD).
- * As for PUD huge maps, we must make sure that we have at least
- * 3 levels, i.e, PMD is not folded.
- */
- if (vma_pagesize == PMD_SIZE ||
- (vma_pagesize == PUD_SIZE && kvm_stage2_has_pmd(kvm)))
- gfn = (fault_ipa & huge_page_mask(hstate_vma(vma))) >> PAGE_SHIFT;
+ if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
+ fault_ipa &= huge_page_mask(hstate_vma(vma));
+
+ gfn = fault_ipa >> PAGE_SHIFT;
mmap_read_unlock(current->mm);
- /* We need minimum second+third level pages */
- ret = kvm_mmu_topup_memory_cache(memcache, kvm_mmu_cache_min_pages(kvm));
- if (ret)
- return ret;
+ /*
+ * Permission faults just need to update the existing leaf entry,
+ * and so normally don't require allocations from the memcache. The
+ * only exception to this is when dirty logging is enabled at runtime
+ * and a write fault needs to collapse a block entry into a table.
+ */
+ if (fault_status != FSC_PERM || (logging_active && write_fault)) {
+ ret = kvm_mmu_topup_memory_cache(memcache,
+ kvm_mmu_cache_min_pages(kvm));
+ if (ret)
+ return ret;
+ }
mmu_seq = vcpu->kvm->mmu_notifier_seq;
/*
@@ -1581,28 +1584,20 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
return -EFAULT;
if (kvm_is_device_pfn(pfn)) {
- mem_type = PAGE_S2_DEVICE;
- flags |= KVM_S2PTE_FLAG_IS_IOMAP;
- } else if (logging_active) {
- /*
- * Faults on pages in a memslot with logging enabled
- * should not be mapped with huge pages (it introduces churn
- * and performance degradation), so force a pte mapping.
- */
- flags |= KVM_S2_FLAG_LOGGING_ACTIVE;
-
+ device = true;
+ } else if (logging_active && !write_fault) {
/*
* Only actually map the page as writable if this was a write
* fault.
*/
- if (!write_fault)
- writable = false;
+ writable = false;
}
- if (exec_fault && is_iomap(flags))
+ if (exec_fault && device)
return -ENOEXEC;
spin_lock(&kvm->mmu_lock);
+ pgt = vcpu->arch.hw_mmu->pgt;
if (mmu_notifier_retry(kvm, mmu_seq))
goto out_unlock;
@@ -1613,62 +1608,31 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
if (vma_pagesize == PAGE_SIZE && !force_pte)
vma_pagesize = transparent_hugepage_adjust(memslot, hva,
&pfn, &fault_ipa);
- if (writable)
+ if (writable) {
+ prot |= KVM_PGTABLE_PROT_W;
kvm_set_pfn_dirty(pfn);
+ mark_page_dirty(kvm, gfn);
+ }
- if (fault_status != FSC_PERM && !is_iomap(flags))
+ if (fault_status != FSC_PERM && !device)
clean_dcache_guest_page(pfn, vma_pagesize);
- if (exec_fault)
+ if (exec_fault) {
+ prot |= KVM_PGTABLE_PROT_X;
invalidate_icache_guest_page(pfn, vma_pagesize);
+ }
- /*
- * If we took an execution fault we have made the
- * icache/dcache coherent above and should now let the s2
- * mapping be executable.
- *
- * Write faults (!exec_fault && FSC_PERM) are orthogonal to
- * execute permissions, and we preserve whatever we have.
- */
- needs_exec = exec_fault ||
- (fault_status == FSC_PERM &&
- stage2_is_exec(mmu, fault_ipa, vma_pagesize));
-
- if (vma_pagesize == PUD_SIZE) {
- pud_t new_pud = kvm_pfn_pud(pfn, mem_type);
-
- new_pud = kvm_pud_mkhuge(new_pud);
- if (writable)
- new_pud = kvm_s2pud_mkwrite(new_pud);
-
- if (needs_exec)
- new_pud = kvm_s2pud_mkexec(new_pud);
-
- ret = stage2_set_pud_huge(mmu, memcache, fault_ipa, &new_pud);
- } else if (vma_pagesize == PMD_SIZE) {
- pmd_t new_pmd = kvm_pfn_pmd(pfn, mem_type);
-
- new_pmd = kvm_pmd_mkhuge(new_pmd);
-
- if (writable)
- new_pmd = kvm_s2pmd_mkwrite(new_pmd);
-
- if (needs_exec)
- new_pmd = kvm_s2pmd_mkexec(new_pmd);
+ if (device)
+ prot |= KVM_PGTABLE_PROT_DEVICE;
+ else if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC))
+ prot |= KVM_PGTABLE_PROT_X;
- ret = stage2_set_pmd_huge(mmu, memcache, fault_ipa, &new_pmd);
+ if (fault_status == FSC_PERM && !(logging_active && writable)) {
+ ret = kvm_pgtable_stage2_relax_perms(pgt, fault_ipa, prot);
} else {
- pte_t new_pte = kvm_pfn_pte(pfn, mem_type);
-
- if (writable) {
- new_pte = kvm_s2pte_mkwrite(new_pte);
- mark_page_dirty(kvm, gfn);
- }
-
- if (needs_exec)
- new_pte = kvm_s2pte_mkexec(new_pte);
-
- ret = stage2_set_pte(mmu, memcache, fault_ipa, &new_pte, flags);
+ ret = kvm_pgtable_stage2_map(pgt, fault_ipa, vma_pagesize,
+ __pfn_to_phys(pfn), prot,
+ memcache);
}
out_unlock:
--
2.28.0.618.gf4bc123cb7-goog
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