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KVM: arm64: Simplify integration of adjust_nested_*_perms()

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Instead of passing pointers to adjust_nested_*_perms(), allow
them to return a new set of permissions.

With some careful moving around so that the canonical permissions
are computed before the nested ones are applied, we end-up with
a bit less code, and something a bit more readable.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Marc Zyngier 2026-03-15 14:58:44 +00:00
parent adb70b3a8b
commit fb9888fdfa
1 changed files with 27 additions and 35 deletions
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62
arch/arm64/kvm/mmu.c
View File

@ -1541,25 +1541,27 @@ static int topup_mmu_memcache(struct kvm_vcpu *vcpu, void *memcache)
* TLB invalidation from the guest and used to limit the invalidation scope if a
* TTL hint or a range isn't provided.
*/
static void adjust_nested_fault_perms(struct kvm_s2_trans *nested,
enum kvm_pgtable_prot *prot,
bool *writable)
static enum kvm_pgtable_prot adjust_nested_fault_perms(struct kvm_s2_trans *nested,
enum kvm_pgtable_prot prot)
{
*writable &= kvm_s2_trans_writable(nested);
if (!kvm_s2_trans_writable(nested))
prot &= ~KVM_PGTABLE_PROT_W;
if (!kvm_s2_trans_readable(nested))
*prot &= ~KVM_PGTABLE_PROT_R;
prot &= ~KVM_PGTABLE_PROT_R;
*prot |= kvm_encode_nested_level(nested);
return prot | kvm_encode_nested_level(nested);
}
static void adjust_nested_exec_perms(struct kvm *kvm,
struct kvm_s2_trans *nested,
enum kvm_pgtable_prot *prot)
static enum kvm_pgtable_prot adjust_nested_exec_perms(struct kvm *kvm,
struct kvm_s2_trans *nested,
enum kvm_pgtable_prot prot)
{
if (!kvm_s2_trans_exec_el0(kvm, nested))
*prot &= ~KVM_PGTABLE_PROT_UX;
prot &= ~KVM_PGTABLE_PROT_UX;
if (!kvm_s2_trans_exec_el1(kvm, nested))
*prot &= ~KVM_PGTABLE_PROT_PX;
prot &= ~KVM_PGTABLE_PROT_PX;
return prot;
}
struct kvm_s2_fault_desc {
@ -1574,7 +1576,7 @@ static int gmem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
struct kvm_s2_trans *nested,
struct kvm_memory_slot *memslot, bool is_perm)
{
bool write_fault, exec_fault, writable;
bool write_fault, exec_fault;
enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_SHARED;
enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
struct kvm_pgtable *pgt = vcpu->arch.hw_mmu->pgt;
@ -1612,19 +1614,17 @@ static int gmem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
return ret;
}
writable = !(memslot->flags & KVM_MEM_READONLY);
if (!(memslot->flags & KVM_MEM_READONLY))
prot |= KVM_PGTABLE_PROT_W;
if (nested)
adjust_nested_fault_perms(nested, &prot, &writable);
if (writable)
prot |= KVM_PGTABLE_PROT_W;
prot = adjust_nested_fault_perms(nested, prot);
if (exec_fault || cpus_have_final_cap(ARM64_HAS_CACHE_DIC))
prot |= KVM_PGTABLE_PROT_X;
if (nested)
adjust_nested_exec_perms(kvm, nested, &prot);
prot = adjust_nested_exec_perms(kvm, nested, prot);
kvm_fault_lock(kvm);
if (mmu_invalidate_retry(kvm, mmu_seq)) {
@ -1637,10 +1637,10 @@ static int gmem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
memcache, flags);
out_unlock:
kvm_release_faultin_page(kvm, page, !!ret, writable);
kvm_release_faultin_page(kvm, page, !!ret, prot & KVM_PGTABLE_PROT_W);
kvm_fault_unlock(kvm);
if (writable && !ret)
if ((prot & KVM_PGTABLE_PROT_W) && !ret)
mark_page_dirty_in_slot(kvm, memslot, gfn);
return ret != -EAGAIN ? ret : 0;
@ -1854,16 +1854,6 @@ static int kvm_s2_fault_compute_prot(const struct kvm_s2_fault_desc *s2fd,
enum kvm_pgtable_prot *prot)
{
struct kvm *kvm = s2fd->vcpu->kvm;
bool writable = s2vi->map_writable;
if (!s2vi->device && memslot_is_logging(s2fd->memslot) &&
!kvm_is_write_fault(s2fd->vcpu)) {
/*
* Only actually map the page as writable if this was a write
* fault.
*/
writable = false;
}
if (kvm_vcpu_trap_is_exec_fault(s2fd->vcpu) && s2vi->map_non_cacheable)
return -ENOEXEC;
@ -1881,12 +1871,14 @@ static int kvm_s2_fault_compute_prot(const struct kvm_s2_fault_desc *s2fd,
*prot = KVM_PGTABLE_PROT_R;
if (s2fd->nested)
adjust_nested_fault_perms(s2fd->nested, prot, &writable);
if (writable)
if (s2vi->map_writable && (s2vi->device ||
!memslot_is_logging(s2fd->memslot) ||
kvm_is_write_fault(s2fd->vcpu)))
*prot |= KVM_PGTABLE_PROT_W;
if (s2fd->nested)
*prot = adjust_nested_fault_perms(s2fd->nested, *prot);
if (kvm_vcpu_trap_is_exec_fault(s2fd->vcpu))
*prot |= KVM_PGTABLE_PROT_X;
@ -1897,7 +1889,7 @@ static int kvm_s2_fault_compute_prot(const struct kvm_s2_fault_desc *s2fd,
*prot |= KVM_PGTABLE_PROT_X;
if (s2fd->nested)
adjust_nested_exec_perms(kvm, s2fd->nested, prot);
*prot = adjust_nested_exec_perms(kvm, s2fd->nested, *prot);
if (!kvm_s2_fault_is_perm(s2fd) && !s2vi->map_non_cacheable && kvm_has_mte(kvm)) {
/* Check the VMM hasn't introduced a new disallowed VMA */