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KVM: arm64: Make fault_ipa immutable

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Updating fault_ipa is conceptually annoying, as it changes something
that is a property of the fault itself.

Stop doing so and instead use fault->gfn as the sole piece of state
that can be used to represent the faulting IPA.

At the same time, introduce get_canonical_gfn() for the couple of case
we're we are concerned with the memslot-related IPA and not the faulting
one.

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 2026-03-08 12:18:29 +00:00
parent 5729560e2c
commit f583a53c2b
1 changed files with 26 additions and 12 deletions
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38
arch/arm64/kvm/mmu.c
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@ -1400,10 +1400,10 @@ static bool fault_supports_stage2_huge_mapping(struct kvm_memory_slot *memslot,
*/
static long
transparent_hugepage_adjust(struct kvm *kvm, struct kvm_memory_slot *memslot,
unsigned long hva, kvm_pfn_t *pfnp,
phys_addr_t *ipap)
unsigned long hva, kvm_pfn_t *pfnp, gfn_t *gfnp)
{
kvm_pfn_t pfn = *pfnp;
gfn_t gfn = *gfnp;
/*
* Make sure the adjustment is done only for THP pages. Also make
@ -1419,7 +1419,8 @@ transparent_hugepage_adjust(struct kvm *kvm, struct kvm_memory_slot *memslot,
if (sz < PMD_SIZE)
return PAGE_SIZE;
*ipap &= PMD_MASK;
gfn &= ~(PTRS_PER_PMD - 1);
*gfnp = gfn;
pfn &= ~(PTRS_PER_PMD - 1);
*pfnp = pfn;
@ -1735,7 +1736,6 @@ static int kvm_s2_fault_get_vma_info(struct kvm_s2_fault *fault)
{
struct vm_area_struct *vma;
struct kvm *kvm = fault->vcpu->kvm;
phys_addr_t ipa;
mmap_read_lock(current->mm);
vma = vma_lookup(current->mm, fault->hva);
@ -1753,9 +1753,7 @@ static int kvm_s2_fault_get_vma_info(struct kvm_s2_fault *fault)
* mapping size to ensure we find the right PFN and lay down the
* mapping in the right place.
*/
fault->fault_ipa = ALIGN_DOWN(fault->fault_ipa, fault->vma_pagesize);
ipa = fault->nested ? kvm_s2_trans_output(fault->nested) : fault->fault_ipa;
fault->gfn = ALIGN_DOWN(ipa, fault->vma_pagesize) >> PAGE_SHIFT;
fault->gfn = ALIGN_DOWN(fault->fault_ipa, fault->vma_pagesize) >> PAGE_SHIFT;
fault->mte_allowed = kvm_vma_mte_allowed(vma);
@ -1777,6 +1775,17 @@ static int kvm_s2_fault_get_vma_info(struct kvm_s2_fault *fault)
return 0;
}
static gfn_t get_canonical_gfn(struct kvm_s2_fault *fault)
{
phys_addr_t ipa;
if (!fault->nested)
return fault->gfn;
ipa = kvm_s2_trans_output(fault->nested);
return ALIGN_DOWN(ipa, fault->vma_pagesize) >> PAGE_SHIFT;
}
static int kvm_s2_fault_pin_pfn(struct kvm_s2_fault *fault)
{
int ret;
@ -1785,7 +1794,7 @@ static int kvm_s2_fault_pin_pfn(struct kvm_s2_fault *fault)
if (ret)
return ret;
fault->pfn = __kvm_faultin_pfn(fault->memslot, fault->gfn,
fault->pfn = __kvm_faultin_pfn(fault->memslot, get_canonical_gfn(fault),
fault->write_fault ? FOLL_WRITE : 0,
&fault->writable, &fault->page);
if (unlikely(is_error_noslot_pfn(fault->pfn))) {
@ -1885,6 +1894,11 @@ static int kvm_s2_fault_compute_prot(struct kvm_s2_fault *fault)
return 0;
}
static phys_addr_t get_ipa(const struct kvm_s2_fault *fault)
{
return gfn_to_gpa(fault->gfn);
}
static int kvm_s2_fault_map(struct kvm_s2_fault *fault, void *memcache)
{
struct kvm *kvm = fault->vcpu->kvm;
@ -1909,7 +1923,7 @@ static int kvm_s2_fault_map(struct kvm_s2_fault *fault, void *memcache)
} else {
fault->vma_pagesize = transparent_hugepage_adjust(kvm, fault->memslot,
fault->hva, &fault->pfn,
&fault->fault_ipa);
&fault->gfn);
if (fault->vma_pagesize < 0) {
ret = fault->vma_pagesize;
@ -1932,10 +1946,10 @@ static int kvm_s2_fault_map(struct kvm_s2_fault *fault, void *memcache)
* PTE, which will be preserved.
*/
fault->prot &= ~KVM_NV_GUEST_MAP_SZ;
ret = KVM_PGT_FN(kvm_pgtable_stage2_relax_perms)(pgt, fault->fault_ipa,
ret = KVM_PGT_FN(kvm_pgtable_stage2_relax_perms)(pgt, get_ipa(fault),
fault->prot, flags);
} else {
ret = KVM_PGT_FN(kvm_pgtable_stage2_map)(pgt, fault->fault_ipa, fault->vma_pagesize,
ret = KVM_PGT_FN(kvm_pgtable_stage2_map)(pgt, get_ipa(fault), fault->vma_pagesize,
__pfn_to_phys(fault->pfn), fault->prot,
memcache, flags);
}
@ -1946,7 +1960,7 @@ static int kvm_s2_fault_map(struct kvm_s2_fault *fault, void *memcache)
/* Mark the page dirty only if the fault is handled successfully */
if (fault->writable && !ret)
mark_page_dirty_in_slot(kvm, fault->memslot, fault->gfn);
mark_page_dirty_in_slot(kvm, fault->memslot, get_canonical_gfn(fault));
if (ret != -EAGAIN)
return ret;