[PATCH 4/6] KVM: arm64: Switch pKVM host S2 over to KVM_PGTABLE_S2_AS_S1

Marc Zyngier
2026-01-19T10:56:57Z

Since we have the basics to use the S1 memory attributes as the
final ones with FWB, flip the host over to that when FWB is present.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 49db32f3ddf71..38f66a56a7665 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -19,7 +19,7 @@
#include <nvhe/mem_protect.h>
#include <nvhe/mm.h>

-#define KVM_HOST_S2_FLAGS (KVM_PGTABLE_S2_NOFWB | KVM_PGTABLE_S2_IDMAP)
+#define KVM_HOST_S2_FLAGS (KVM_PGTABLE_S2_AS_S1 | KVM_PGTABLE_S2_IDMAP)

struct host_mmu host_mmu;

@@ -324,6 +324,8 @@ int __pkvm_prot_finalize(void)
params->vttbr = kvm_get_vttbr(mmu);
params->vtcr = mmu->vtcr;
params->hcr_el2 |= HCR_VM;
+ if (cpus_have_final_cap(ARM64_HAS_STAGE2_FWB))
+ params->hcr_el2 |= HCR_FWB;

/*
* The CMO below not only cleans the updated params to the
--
2.47.3