Commit e314a4db authored by Marc Zyngier's avatar Marc Zyngier
Browse files

KVM: arm64: Move device mapping management into kvm_s2_fault_pin_pfn() 



Attributes computed for devices are computed very late in the fault
handling process, meanning they are mutable for that long.

Introduce both 'device' and 'map_non_cacheable' attributes to the
vma_info structure, allowing that information to be set in stone
earlier, in kvm_s2_fault_pin_pfn().

Tested-by: default avatarFuad Tabba <tabba@google.com>
Reviewed-by: default avatarFuad Tabba <tabba@google.com>
Reviewed-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 29a56818

arch/arm64/kvm/mmu.c

+29 −23
Original line number Diff line number Diff line
@@ -1654,9 +1654,11 @@ struct kvm_s2_fault_vma_info { 
	struct page	*page;

	kvm_pfn_t	pfn;

	gfn_t		gfn;

	bool		device;

	bool		mte_allowed;

	bool		is_vma_cacheable;

	bool		map_writable;

	bool		map_non_cacheable;

};



static short kvm_s2_resolve_vma_size(const struct kvm_s2_fault_desc *s2fd,
@@ -1726,7 +1728,6 @@ static short kvm_s2_resolve_vma_size(const struct kvm_s2_fault_desc *s2fd, 
}



struct kvm_s2_fault {

	bool s2_force_noncacheable;

	enum kvm_pgtable_prot prot;

};
@@ -1736,7 +1737,6 @@ static bool kvm_s2_fault_is_perm(const struct kvm_s2_fault_desc *s2fd) 
}



static int kvm_s2_fault_get_vma_info(const struct kvm_s2_fault_desc *s2fd,

				     struct kvm_s2_fault *fault,

				     struct kvm_s2_fault_vma_info *s2vi)

{

	struct vm_area_struct *vma;
@@ -1792,12 +1792,11 @@ static gfn_t get_canonical_gfn(const struct kvm_s2_fault_desc *s2fd, 
}



static int kvm_s2_fault_pin_pfn(const struct kvm_s2_fault_desc *s2fd,

				struct kvm_s2_fault *fault,

				struct kvm_s2_fault_vma_info *s2vi)

{

	int ret;



	ret = kvm_s2_fault_get_vma_info(s2fd, fault, s2vi);

	ret = kvm_s2_fault_get_vma_info(s2fd, s2vi);

	if (ret)

		return ret;
@@ -1812,16 +1811,6 @@ static int kvm_s2_fault_pin_pfn(const struct kvm_s2_fault_desc *s2fd, 
		return -EFAULT;

	}



	return 1;

}



static int kvm_s2_fault_compute_prot(const struct kvm_s2_fault_desc *s2fd,

				     struct kvm_s2_fault *fault,

				     const struct kvm_s2_fault_vma_info *s2vi)

{

	struct kvm *kvm = s2fd->vcpu->kvm;

	bool writable = s2vi->map_writable;



	/*

	 * Check if this is non-struct page memory PFN, and cannot support

	 * CMOs. It could potentially be unsafe to access as cacheable.
@@ -1840,8 +1829,10 @@ static int kvm_s2_fault_compute_prot(const struct kvm_s2_fault_desc *s2fd, 
			 * S2FWB and CACHE DIC are mandatory to avoid the need for

			 * cache maintenance.

			 */

			if (!kvm_supports_cacheable_pfnmap())

			if (!kvm_supports_cacheable_pfnmap()) {

				kvm_release_faultin_page(s2fd->vcpu->kvm, s2vi->page, true, false);

				return -EFAULT;

			}

		} else {

			/*

			 * If the page was identified as device early by looking at
@@ -1853,9 +1844,24 @@ static int kvm_s2_fault_compute_prot(const struct kvm_s2_fault_desc *s2fd, 
			 * In both cases, we don't let transparent_hugepage_adjust()

			 * change things at the last minute.

			 */

			fault->s2_force_noncacheable = true;

			s2vi->map_non_cacheable = true;

		}

	} else if (memslot_is_logging(s2fd->memslot) && !kvm_is_write_fault(s2fd->vcpu)) {



		s2vi->device = true;

	}



	return 1;

}



static int kvm_s2_fault_compute_prot(const struct kvm_s2_fault_desc *s2fd,

				     struct kvm_s2_fault *fault,

				     const struct kvm_s2_fault_vma_info *s2vi)

{

	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.
@@ -1863,7 +1869,7 @@ static int kvm_s2_fault_compute_prot(const struct kvm_s2_fault_desc *s2fd, 
		writable = false;

	}



	if (kvm_vcpu_trap_is_exec_fault(s2fd->vcpu) && fault->s2_force_noncacheable)

	if (kvm_vcpu_trap_is_exec_fault(s2fd->vcpu) && s2vi->map_non_cacheable)

		return -ENOEXEC;



	/*
@@ -1886,7 +1892,7 @@ static int kvm_s2_fault_compute_prot(const struct kvm_s2_fault_desc *s2fd, 
	if (kvm_vcpu_trap_is_exec_fault(s2fd->vcpu))

		fault->prot |= KVM_PGTABLE_PROT_X;



	if (fault->s2_force_noncacheable)

	if (s2vi->map_non_cacheable)

		fault->prot |= (s2vi->vm_flags & VM_ALLOW_ANY_UNCACHED) ?

			       KVM_PGTABLE_PROT_NORMAL_NC : KVM_PGTABLE_PROT_DEVICE;

	else if (cpus_have_final_cap(ARM64_HAS_CACHE_DIC))
@@ -1895,7 +1901,7 @@ static int kvm_s2_fault_compute_prot(const struct kvm_s2_fault_desc *s2fd, 
	if (s2fd->nested)

		adjust_nested_exec_perms(kvm, s2fd->nested, &fault->prot);



	if (!kvm_s2_fault_is_perm(s2fd) && !fault->s2_force_noncacheable && kvm_has_mte(kvm)) {

	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 */

		if (!s2vi->mte_allowed)

			return -EFAULT;
@@ -1935,7 +1941,7 @@ static int kvm_s2_fault_map(const struct kvm_s2_fault_desc *s2fd, 
	 * backed by a THP and thus use block mapping if possible.

	 */

	if (mapping_size == PAGE_SIZE &&

	    !(s2vi->max_map_size == PAGE_SIZE || fault->s2_force_noncacheable)) {

	    !(s2vi->max_map_size == PAGE_SIZE || s2vi->map_non_cacheable)) {

		if (perm_fault_granule > PAGE_SIZE) {

			mapping_size = perm_fault_granule;

		} else {
@@ -1949,7 +1955,7 @@ static int kvm_s2_fault_map(const struct kvm_s2_fault_desc *s2fd, 
		}

	}



	if (!perm_fault_granule && !fault->s2_force_noncacheable && kvm_has_mte(kvm))

	if (!perm_fault_granule && !s2vi->map_non_cacheable && kvm_has_mte(kvm))

		sanitise_mte_tags(kvm, pfn, mapping_size);



	/*
@@ -2019,7 +2025,7 @@ static int user_mem_abort(const struct kvm_s2_fault_desc *s2fd) 
	 * Let's check if we will get back a huge page backed by hugetlbfs, or

	 * get block mapping for device MMIO region.

	 */

	ret = kvm_s2_fault_pin_pfn(s2fd, &fault, &s2vi);

	ret = kvm_s2_fault_pin_pfn(s2fd, &s2vi);

	if (ret != 1)

		return ret;