kernel.git/arch/arm64/kvm/config.c, branch master

KVM: arm64: Add sanitisation to SCTLR_EL2

2026-02-05T09:02:13Z

Sanitise SCTLR_EL2 the usual way. The most important aspect of this is that we benefit from SCTLR_EL2.SPAN being RES1 when HCR_EL2.E2H==0. Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Link: https://patch.msgid.link/20260202184329.2724080-20-maz@kernel.org Signed-off-by: Marc Zyngier

KVM: arm64: Remove all traces of HCR_EL2.MIOCNCE

2026-02-05T09:02:13Z

MIOCNCE had the potential to eat your data, and also was never implemented by anyone. It's been retrospectively removed from the architecture, and we're happy to follow that lead. Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Link: https://patch.msgid.link/20260202184329.2724080-19-maz@kernel.org Signed-off-by: Marc Zyngier

KVM: arm64: Remove all traces of FEAT_TME

2026-02-05T09:02:13Z

FEAT_TME has been dropped from the architecture. Retrospectively. I'm sure someone is crying somewhere, but most of us won't. Clean-up time. Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Link: https://patch.msgid.link/20260202184329.2724080-18-maz@kernel.org Signed-off-by: Marc Zyngier

KVM: arm64: Simplify handling of full register invalid constraint

2026-02-05T09:02:13Z

Now that we embed the RESx bits in the register description, it becomes easier to deal with registers that are simply not valid, as their existence is not satisfied by the configuration (SCTLR2_ELx without FEAT_SCTLR2, for example). Such registers essentially become RES0 for any bit that wasn't already advertised as RESx. Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Link: https://patch.msgid.link/20260202184329.2724080-17-maz@kernel.org Signed-off-by: Marc Zyngier

KVM: arm64: Get rid of FIXED_VALUE altogether

2026-02-05T09:02:13Z

We have now killed every occurrences of FIXED_VALUE, and we can therefore drop the whole infrastructure. Good riddance. Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Link: https://patch.msgid.link/20260202184329.2724080-16-maz@kernel.org Signed-off-by: Marc Zyngier

KVM: arm64: Simplify handling of HCR_EL2.E2H RESx

2026-02-05T09:02:13Z

Now that we can link the RESx behaviour with the value of HCR_EL2.E2H, we can trivially express the tautological constraint that makes E2H a reserved value at all times. Fun, isn't it? Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Link: https://patch.msgid.link/20260202184329.2724080-15-maz@kernel.org Signed-off-by: Marc Zyngier

KVM: arm64: Move RESx into individual register descriptors

2026-02-05T09:02:13Z

Instead of hacking the RES1 bits at runtime, move them into the register descriptors. This makes it significantly nicer. Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Link: https://patch.msgid.link/20260202184329.2724080-14-maz@kernel.org Signed-off-by: Marc Zyngier

KVM: arm64: Add RES1_WHEN_E2Hx constraints as configuration flags

2026-02-05T09:02:12Z

"Thanks" to VHE, SCTLR_EL2 radically changes shape depending on the value of HCR_EL2.E2H, as a lot of the bits that didn't have much meaning with E2H=0 start impacting EL0 with E2H=1. This has a direct impact on the RESx behaviour of these bits, and we need a way to express them. For this purpose, introduce two new constaints that, when the controlling feature is not present, force the field to RES1 depending on the value of E2H. Note that RES0 is still implicit, This allows diverging RESx values depending on the value of E2H, something that is required by a bunch of SCTLR_EL2 bits. Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Link: https://patch.msgid.link/20260202184329.2724080-13-maz@kernel.org Signed-off-by: Marc Zyngier

KVM: arm64: Add REQUIRES_E2H1 constraint as configuration flags

2026-02-05T09:01:41Z

A bunch of EL2 configuration are very similar to their EL1 counterpart, with the added constraint that HCR_EL2.E2H being 1. For us, this means HCR_EL2.E2H being RES1, which is something we can statically evaluate. Add a REQUIRES_E2H1 constraint, which allows us to express conditions in a much simpler way (without extra code). Existing occurrences are converted, before we add a lot more. Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Link: https://patch.msgid.link/20260202184329.2724080-12-maz@kernel.org Signed-off-by: Marc Zyngier

KVM: arm64: Simplify FIXED_VALUE handling

2026-02-05T09:01:41Z

The FIXED_VALUE qualifier (mostly used for HCR_EL2) is pointlessly complicated, as it tries to piggy-back on the previous RES0 handling while being done in a different phase, on different data. Instead, make it an integral part of the RESx computation, and allow it to directly set RESx bits. This is much easier to understand. It also paves the way for some additional changes to that will allow the full removal of the FIXED_VALUE handling. Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Link: https://patch.msgid.link/20260202184329.2724080-11-maz@kernel.org Signed-off-by: Marc Zyngier