Thread (8 messages) 8 messages, 2 authors, 2026-01-25

Re: [PATCH v2 3/5] KVM: arm64: Switch pKVM host S2 over to KVM_PGTABLE_S2_AS_S1

From: Fuad Tabba <tabba@google.com>
Date: 2026-01-25 13:51:09
Also in: kvmarm

On Fri, 23 Jan 2026 at 19:16, Marc Zyngier [off-list ref] wrote:
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.

Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Fuad Tabba <tabba@google.com>

Cheers,
/fuad
quoted hunk ↗ jump to hunk
---
 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
  
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