kernel/linux.git/arch/arm64/include/asm/kvm_nested.h, branch v7.1

KVM: arm64: nv: Fix handling of XN[0] when !FEAT_XNX

2026-06-05T13:07:06+00:00

XN has already been extracted from its bitfield position so using FIELD_PREP() on the mask that clears XN[0] is completely broken, having the effect of unconditionally granting execute permissions... Fix the obvious mistake by manipulating the right bit. Cc: stable@vger.kernel.org Fixes: d93febe2ed2e ("KVM: arm64: nv: Forward FEAT_XNX permissions to the shadow stage-2") Reviewed-by: Wei-Lin Chang Signed-off-by: Oliver Upton Link: https://patch.msgid.link/20260602165901.52800-2-oupton@kernel.org Signed-off-by: Marc Zyngier

KVM: arm64: nv: Consider the DS bit when translating TCR_EL2

2026-05-06T16:08:39+00:00

When running an nVHE L1, TCR_EL2 is mapped to TCR_EL1. Writes to the register are trapped and written to TCR_EL1 after a translation. Booting an nVHE L1 with 52-bit VA isn't working because the translation was ignoring the DS bit set by the guest, hence causing repeating level 0 faults. Add it in the translation function. Signed-off-by: Wei-Lin Chang Link: https://patch.msgid.link/20260505144735.1496530-1-weilin.chang@arm.com Signed-off-by: Marc Zyngier

KVM: arm64: Deduplicate ASID retrieval code

2026-02-25T12:19:33+00:00

We currently have three versions of the ASID retrieval code, one in the S1 walker, and two in the VNCR handling (although the last two are limited to the EL2&0 translation regime). Make this code common, and take this opportunity to also simplify the code a bit while switching over to the TTBRx_EL1_ASID macro. Reviewed-by: Joey Gouly Reviewed-by: Jonathan Cameron Link: https://patch.msgid.link/20260225104718.14209-1-maz@kernel.org Signed-off-by: Marc Zyngier

KVM: arm64: Implement HW access flag management in stage-1 SW PTW

2025-12-01T08:44:02+00:00

Atomically update the Access flag at stage-1 when the guest has configured the MMU to do so. Make the implementation choice (and liberal interpretation of speculation) that any access type updates the Access flag, including AT and CMO instructions. Restart the entire walk by returning to the exception-generating instruction in the case of a failed Access flag update. Reviewed-by: Marc Zyngier Tested-by: Marc Zyngier Link: https://msgid.link/20251124190158.177318-13-oupton@kernel.org Signed-off-by: Oliver Upton

KVM: arm64: Add helper for swapping guest descriptor

2025-12-01T08:44:02+00:00

Implementing FEAT_HAFDBS in KVM's software PTWs requires the ability to CAS a descriptor to update the in-memory value. Add an accessor to do exactly that, coping with the fact that guest descriptors are in user memory (duh). While FEAT_LSE required on any system that implements NV, KVM now uses the stage-1 PTW for non-nested use cases meaning an LL/SC implementation is necessary as well. Reviewed-by: Marc Zyngier Tested-by: Marc Zyngier Link: https://msgid.link/20251124190158.177318-11-oupton@kernel.org Signed-off-by: Oliver Upton

KVM: arm64: nv: Forward FEAT_XNX permissions to the shadow stage-2

2025-11-24T22:24:45+00:00

Add support for FEAT_XNX to shadow stage-2 MMUs, being careful to only evaluate XN[0] when the feature is actually exposed to the VM. Restructure the layering of permissions in the fault handler to assume pX and uX then restricting based on the guest's stage-2 afterwards. Reviewed-by: Marc Zyngier Tested-by: Marc Zyngier Link: https://msgid.link/20251124190158.177318-4-oupton@kernel.org Signed-off-by: Oliver Upton

Merge branch kvm-arm64/nv-debug into kvmarm-master/next

2025-09-20T11:26:11+00:00

* kvm-arm64/nv-debug: : . : Fix handling of MDSCR_EL1 in NV context, which is unfortunately : mishandled by the architecture. Patches courtesy of Oliver Upton : (20250917203125.283116-2-oliver.upton@linux.dev) : . KVM: arm64: nv: Apply guest's MDCR traps in nested context KVM: arm64: nv: Trap debug registers when in hyp context Signed-off-by: Marc Zyngier

KVM: arm64: Add S1 IPA to page table level walker

2025-09-20T10:05:14+00:00

Use the filtering hook infrastructure to implement a new walker that, for a given VA and an IPA, returns the level of the first occurence of this IPA in the walk from that VA. This will be used to improve our SEA syndrome reporting. Reviewed-by: Oliver Upton Signed-off-by: Marc Zyngier

KVM: arm64: Add filtering hook to S1 page table walk

2025-09-20T10:05:13+00:00

Add a filtering hook that can get called on each level of the walk, and providing access to the full state. Crucially, this is called *before* the access is made, so that it is possible to track down the level of a faulting access. Reviewed-by: Oliver Upton Signed-off-by: Marc Zyngier

KVM: arm64: Compute shareability for LPA2

2025-09-20T10:05:12+00:00

LPA2 gets the memory access shareability from TCR_ELx instead of getting it form the descriptors. Store it in the walk info struct so that it is passed around and evaluated as required. Reviewed-by: Oliver Upton Signed-off-by: Marc Zyngier