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KVM: arm64: Add a range to pkvm_mappings

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In preparation for supporting stage-2 huge mappings for np-guest, add a
nr_pages member for pkvm_mappings to allow EL1 to track the size of the
stage-2 mapping.

Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/r/20250521124834.1070650-9-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Quentin Perret 2025-05-21 13:48:32 +01:00 • committed by Marc Zyngier
parent b38c9775f7
commit 3669ddd8fa
2 changed files with 29 additions and 9 deletions
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1
arch/arm64/include/asm/kvm_pkvm.h
View file

@ -173,6 +173,7 @@ struct pkvm_mapping {
struct rb_node node;
u64 gfn;
u64 pfn;
u64 nr_pages;
u64 __subtree_last; /* Internal member for interval tree */
};

37
arch/arm64/kvm/pkvm.c
View file

@ -283,7 +283,7 @@ static u64 __pkvm_mapping_start(struct pkvm_mapping *m)
static u64 __pkvm_mapping_end(struct pkvm_mapping *m)
{
return (m->gfn + 1) * PAGE_SIZE - 1;
return (m->gfn + m->nr_pages) * PAGE_SIZE - 1;
}
INTERVAL_TREE_DEFINE(struct pkvm_mapping, node, u64, __subtree_last,
@ -324,7 +324,8 @@ static int __pkvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 start, u64 e
return 0;
for_each_mapping_in_range_safe(pgt, start, end, mapping) {
ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_guest, handle, mapping->gfn, 1);
ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_guest, handle, mapping->gfn,
mapping->nr_pages);
if (WARN_ON(ret))
return ret;
pkvm_mapping_remove(mapping, &pgt->pkvm_mappings);
@ -354,16 +355,32 @@ int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
return -EINVAL;
lockdep_assert_held_write(&kvm->mmu_lock);
ret = kvm_call_hyp_nvhe(__pkvm_host_share_guest, pfn, gfn, 1, prot);
if (ret) {
/* Is the gfn already mapped due to a racing vCPU? */
if (ret == -EPERM)
/*
* Calling stage2_map() on top of existing mappings is either happening because of a race
* with another vCPU, or because we're changing between page and block mappings. As per
* user_mem_abort(), same-size permission faults are handled in the relax_perms() path.
*/
mapping = pkvm_mapping_iter_first(&pgt->pkvm_mappings, addr, addr + size - 1);
if (mapping) {
if (size == (mapping->nr_pages * PAGE_SIZE))
return -EAGAIN;
/* Remove _any_ pkvm_mapping overlapping with the range, bigger or smaller. */
ret = __pkvm_pgtable_stage2_unmap(pgt, addr, addr + size);
if (ret)
return ret;
mapping = NULL;
}
ret = kvm_call_hyp_nvhe(__pkvm_host_share_guest, pfn, gfn, size / PAGE_SIZE, prot);
if (WARN_ON(ret))
return ret;
swap(mapping, cache->mapping);
mapping->gfn = gfn;
mapping->pfn = pfn;
mapping->nr_pages = size / PAGE_SIZE;
pkvm_mapping_insert(mapping, &pgt->pkvm_mappings);
return ret;
@ -385,7 +402,8 @@ int pkvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
lockdep_assert_held(&kvm->mmu_lock);
for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping) {
ret = kvm_call_hyp_nvhe(__pkvm_host_wrprotect_guest, handle, mapping->gfn, 1);
ret = kvm_call_hyp_nvhe(__pkvm_host_wrprotect_guest, handle, mapping->gfn,
mapping->nr_pages);
if (WARN_ON(ret))
break;
}
@ -400,7 +418,8 @@ int pkvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size)
lockdep_assert_held(&kvm->mmu_lock);
for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping)
__clean_dcache_guest_page(pfn_to_kaddr(mapping->pfn), PAGE_SIZE);
__clean_dcache_guest_page(pfn_to_kaddr(mapping->pfn),
PAGE_SIZE * mapping->nr_pages);
return 0;
}
@ -415,7 +434,7 @@ bool pkvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr, u64
lockdep_assert_held(&kvm->mmu_lock);
for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping)
young |= kvm_call_hyp_nvhe(__pkvm_host_test_clear_young_guest, handle, mapping->gfn,
1, mkold);
mapping->nr_pages, mkold);
return young;
}