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KVM: arm64: Convert user_mem_abort() to generic page-table API 

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.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20200911132529.19844-18-will@kernel.org
This commit is contained in:
Will Deacon 2020-09-11 14:25:25 +01:00 committed by Marc Zyngier
parent adcd4e2329
commit 6f745f1bb5
1 changed files with 44 additions and 80 deletions
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124
arch/arm64/kvm/mmu.c
View File

@ -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 (device)
prot |= KVM_PGTABLE_PROT_DEVICE;
else if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC))
prot |= KVM_PGTABLE_PROT_X;
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);
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: