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KVM: arm64: Hook up donation hypercall to pkvm_pgtable_stage2_map()

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Mapping pages into a protected guest requires the donation of memory
from the host.

Extend pkvm_pgtable_stage2_map() to issue a donate hypercall when the
target VM is protected. Since the hypercall only handles a single page,
the splitting logic used for the share path is not required.

Tested-by: Fuad Tabba <tabba@google.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://patch.msgid.link/20260330144841.26181-14-will@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Will Deacon 2026-03-30 15:48:14 +01:00 committed by Marc Zyngier
parent 1e579adca1
commit 5fef16ef49
1 changed files with 41 additions and 17 deletions
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58
arch/arm64/kvm/pkvm.c
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@ -379,31 +379,55 @@ int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
struct kvm_hyp_memcache *cache = mc;
u64 gfn = addr >> PAGE_SHIFT;
u64 pfn = phys >> PAGE_SHIFT;
u64 end = addr + size;
int ret;
if (size != PAGE_SIZE && size != PMD_SIZE)
return -EINVAL;
lockdep_assert_held_write(&kvm->mmu_lock);
mapping = pkvm_mapping_iter_first(&pgt->pkvm_mappings, addr, end - 1);
/*
* 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))
if (kvm_vm_is_protected(kvm)) {
/* Protected VMs are mapped using RWX page-granular mappings */
if (WARN_ON_ONCE(size != PAGE_SIZE))
return -EINVAL;
if (WARN_ON_ONCE(prot != KVM_PGTABLE_PROT_RWX))
return -EINVAL;
/*
* We raced with another vCPU.
*/
if (mapping)
return -EAGAIN;
/* Remove _any_ pkvm_mapping overlapping with the range, bigger or smaller. */
ret = __pkvm_pgtable_stage2_unshare(pgt, addr, addr + size);
if (ret)
return ret;
mapping = NULL;
ret = kvm_call_hyp_nvhe(__pkvm_host_donate_guest, pfn, gfn);
} else {
if (WARN_ON_ONCE(size != PAGE_SIZE && size != PMD_SIZE))
return -EINVAL;
/*
* We either raced with another vCPU or we're changing between
* page and block mappings. As per user_mem_abort(), same-size
* permission faults are handled in the relax_perms() path.
*/
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_unshare(pgt, addr, end);
if (ret)
return ret;
mapping = NULL;
}
ret = kvm_call_hyp_nvhe(__pkvm_host_share_guest, pfn, gfn,
size / PAGE_SIZE, prot);
}
ret = kvm_call_hyp_nvhe(__pkvm_host_share_guest, pfn, gfn, size / PAGE_SIZE, prot);
if (WARN_ON(ret))
return ret;