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KVM: arm64: Simplify the sanitise_mte_tags() logic

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Currently sanitise_mte_tags() checks if it's an online page before
attempting to sanitise the tags. Such detection should be done in the
caller via the VM_MTE_ALLOWED vma flag. Since kvm_set_spte_gfn() does
not have the vma, leave the page unmapped if not already tagged. Tag
initialisation will be done on a subsequent access fault in
user_mem_abort().

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
[pcc@google.com: fix the page initializer]
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Peter Collingbourne <pcc@google.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221104011041.290951-4-pcc@google.com
This commit is contained in:
Catalin Marinas 2022-11-03 18:10:36 -07:00 committed by Marc Zyngier
parent e059853d14
commit 2dbf12ae13
1 changed files with 15 additions and 25 deletions
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40
arch/arm64/kvm/mmu.c
View file

@ -1091,23 +1091,14 @@ static int get_vma_page_shift(struct vm_area_struct *vma, unsigned long hva)
* - mmap_lock protects between a VM faulting a page in and the VMM performing
* an mprotect() to add VM_MTE
*/
static int sanitise_mte_tags(struct kvm *kvm, kvm_pfn_t pfn,
unsigned long size)
static void sanitise_mte_tags(struct kvm *kvm, kvm_pfn_t pfn,
unsigned long size)
{
unsigned long i, nr_pages = size >> PAGE_SHIFT;
struct page *page;
struct page *page = pfn_to_page(pfn);
if (!kvm_has_mte(kvm))
return 0;
/*
* pfn_to_online_page() is used to reject ZONE_DEVICE pages
* that may not support tags.
*/
page = pfn_to_online_page(pfn);
if (!page)
return -EFAULT;
return;
for (i = 0; i < nr_pages; i++, page++) {
if (!page_mte_tagged(page)) {
@ -1115,8 +1106,6 @@ static int sanitise_mte_tags(struct kvm *kvm, kvm_pfn_t pfn,
set_page_mte_tagged(page);
}
}
return 0;
}
static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
@ -1127,7 +1116,6 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
bool write_fault, writable, force_pte = false;
bool exec_fault;
bool device = false;
bool shared;
unsigned long mmu_seq;
struct kvm *kvm = vcpu->kvm;
struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
@ -1177,8 +1165,6 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
vma_shift = get_vma_page_shift(vma, hva);
}
shared = (vma->vm_flags & VM_SHARED);
switch (vma_shift) {
#ifndef __PAGETABLE_PMD_FOLDED
case PUD_SHIFT:
@ -1299,12 +1285,13 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
if (fault_status != FSC_PERM && !device && kvm_has_mte(kvm)) {
/* Check the VMM hasn't introduced a new VM_SHARED VMA */
if (!shared)
ret = sanitise_mte_tags(kvm, pfn, vma_pagesize);
else
if ((vma->vm_flags & VM_MTE_ALLOWED) &&
!(vma->vm_flags & VM_SHARED)) {
sanitise_mte_tags(kvm, pfn, vma_pagesize);
} else {
ret = -EFAULT;
if (ret)
goto out_unlock;
}
}
if (writable)
@ -1526,15 +1513,18 @@ bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
{
kvm_pfn_t pfn = pte_pfn(range->pte);
int ret;
if (!kvm->arch.mmu.pgt)
return false;
WARN_ON(range->end - range->start != 1);
ret = sanitise_mte_tags(kvm, pfn, PAGE_SIZE);
if (ret)
/*
* If the page isn't tagged, defer to user_mem_abort() for sanitising
* the MTE tags. The S2 pte should have been unmapped by
* mmu_notifier_invalidate_range_end().
*/
if (kvm_has_mte(kvm) && !page_mte_tagged(pfn_to_page(pfn)))
return false;
/*