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ANDROID: KVM: arm64: poison/account relinquished pages after unmap

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If the page is poisoned and accounted before the unmap:
1. The guest has a window to access and dirty the page after the
   poison and related CMOs
2. If the unmap fails, the hypercall has visible side effect
   (poisoning) and leaves an incorrect PSCI MEM_PROTECT count.

Bug: 357781595
Bug: 433953177
Change-Id: Id67f2dda632bca686e2509f1c64d08743deef199
Signed-off-by: Keir Fraser <keirf@google.com>
This commit is contained in:
Keir Fraser
2025-07-28 06:41:19 +00:00
parent d64d8b7dab
commit 4736505668
1 changed files with 3 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/arm64/kvm/hyp/nvhe/mem_protect.c
+3 -3
View File
@@ -431,14 +431,14 @@ int __pkvm_guest_relinquish_to_host(struct pkvm_hyp_vcpu *vcpu,
goto end;
}
hyp_poison_page(phys, PAGE_SIZE);
psci_mem_protect_dec(1);
/* Zap the guest stage2 pte and return ownership to the host */
ret = kvm_pgtable_stage2_unmap(&vm->pgt, ipa, PAGE_SIZE);
if (ret)
goto end;
hyp_poison_page(phys, PAGE_SIZE);
psci_mem_protect_dec(1);
WARN_ON(host_stage2_set_owner_locked(phys, PAGE_SIZE, PKVM_ID_HOST));
end:
guest_unlock_component(vm);