Commit 43c47550 authored by Quentin Perret's avatar Quentin Perret Committed by Marc Zyngier
Browse files

KVM: arm64: Unconditionally cross check hyp state 

Now that the hypervisor's state is stored in the hyp_vmemmap, we no
longer need an expensive page-table walk to read it. This means we can
now afford to cross check the hyp-state during all memory ownership
transitions where the hyp is involved unconditionally, hence avoiding
problems such as [1].

[1] https://lore.kernel.org/kvmarm/20241128154406.602875-1-qperret@google.com/



Reviewed-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarQuentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250416152648.2982950-8-qperret@google.com


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 48d84888

arch/arm64/kvm/hyp/nvhe/mem_protect.c

+9 −15
Original line number Diff line number Diff line
@@ -702,11 +702,9 @@ int __pkvm_host_share_hyp(u64 pfn) 
	ret = __host_check_page_state_range(phys, size, PKVM_PAGE_OWNED);

	if (ret)

		goto unlock;

	if (IS_ENABLED(CONFIG_NVHE_EL2_DEBUG)) {

	ret = __hyp_check_page_state_range(phys, size, PKVM_NOPAGE);

	if (ret)

		goto unlock;

	}



	__hyp_set_page_state_range(phys, size, PKVM_PAGE_SHARED_BORROWED);

	WARN_ON(__host_set_page_state_range(phys, size, PKVM_PAGE_SHARED_OWNED));
@@ -762,11 +760,9 @@ int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages) 
	ret = __host_check_page_state_range(phys, size, PKVM_PAGE_OWNED);

	if (ret)

		goto unlock;

	if (IS_ENABLED(CONFIG_NVHE_EL2_DEBUG)) {

	ret = __hyp_check_page_state_range(phys, size, PKVM_NOPAGE);

	if (ret)

		goto unlock;

	}



	__hyp_set_page_state_range(phys, size, PKVM_PAGE_OWNED);

	WARN_ON(pkvm_create_mappings_locked(virt, virt + size, PAGE_HYP));
@@ -792,11 +788,9 @@ int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages) 
	ret = __hyp_check_page_state_range(phys, size, PKVM_PAGE_OWNED);

	if (ret)

		goto unlock;

	if (IS_ENABLED(CONFIG_NVHE_EL2_DEBUG)) {

	ret = __host_check_page_state_range(phys, size, PKVM_NOPAGE);

	if (ret)

		goto unlock;

	}



	__hyp_set_page_state_range(phys, size, PKVM_NOPAGE);

	WARN_ON(kvm_pgtable_hyp_unmap(&pkvm_pgtable, virt, size) != size);