Commit cb163016 authored by Quentin Perret's avatar Quentin Perret Committed by Marc Zyngier
Browse files

KVM: arm64: Issue CMOs when tearing down guest s2 pages 



On the guest teardown path, pKVM will zero the pages used to back
the guest data structures before returning them to the host as
they may contain secrets (e.g. in the vCPU registers). However,
the zeroing is done using a cacheable alias, and CMOs are
missing, hence giving the host a potential opportunity to read
the original content of the guest structs from memory.

Fix this by issuing CMOs after zeroing the pages.

Signed-off-by: default avatarQuentin Perret <qperret@google.com>
Signed-off-by: default avatarFuad Tabba <tabba@google.com>
Acked-by: default avatarOliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-6-tabba@google.com


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 40099ded

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

+1 −0
Original line number Diff line number Diff line
@@ -441,6 +441,7 @@ static void *map_donated_memory(unsigned long host_va, size_t size) 


static void __unmap_donated_memory(void *va, size_t size)

{

	kvm_flush_dcache_to_poc(va, size);

	WARN_ON(__pkvm_hyp_donate_host(hyp_virt_to_pfn(va),

				       PAGE_ALIGN(size) >> PAGE_SHIFT));

}