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path: root/arch/arm64/kvm/at.c
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2024-08-30KVM: arm64: nv: Add support for FEAT_ATS1AMarc Zyngier
Handling FEAT_ATS1A (which provides the AT S1E{1,2}A instructions) is pretty easy, as it is just the usual AT without the permission check. This basically amounts to plumbing the instructions in the various dispatch tables, and handling FEAT_ATS1A being disabled in the ID registers. Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-08-30KVM: arm64: nv: Make AT+PAN instructions aware of FEAT_PAN3Marc Zyngier
FEAT_PAN3 added a check for executable permissions to FEAT_PAN2. Add the required SCTLR_ELx.EPAN and descriptor checks to handle this correctly. Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-08-30KVM: arm64: nv: Add SW walker for AT S1 emulationMarc Zyngier
In order to plug the brokenness of our current AT implementation, we need a SW walker that is going to... err.. walk the S1 tables and tell us what it finds. Of course, it builds on top of our S2 walker, and share similar concepts. The beauty of it is that since it uses kvm_read_guest(), it is able to bring back pages that have been otherwise evicted. This is then plugged in the two AT S1 emulation functions as a "slow path" fallback. I'm not sure it is that slow, but hey. Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-08-30KVM: arm64: nv: Add emulation of AT S12E{0,1}{R,W}Marc Zyngier
On the face of it, AT S12E{0,1}{R,W} is pretty simple. It is the combination of AT S1E{0,1}{R,W}, followed by an extra S2 walk. However, there is a great deal of complexity coming from combining the S1 and S2 attributes to report something consistent in PAR_EL1. This is an absolute mine field, and I have a splitting headache. Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-08-30KVM: arm64: nv: Add basic emulation of AT S1E2{R,W}Marc Zyngier
Similar to our AT S1E{0,1} emulation, we implement the AT S1E2 handling. This emulation of course suffers from the same problems, but is somehow simpler due to the lack of PAN2 and the fact that we are guaranteed to execute it from the correct context. Co-developed-by: Jintack Lim <jintack.lim@linaro.org> Signed-off-by: Jintack Lim <jintack.lim@linaro.org> Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-08-30KVM: arm64: nv: Add basic emulation of AT S1E1{R,W}PMarc Zyngier
Building on top of our primitive AT S1E{0,1}{R,W} emulation, add minimal support for the FEAT_PAN2 instructions, momentary context-switching PSTATE.PAN so that it takes effect in the context of the guest. Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-08-30KVM: arm64: nv: Add basic emulation of AT S1E{0,1}{R,W}Marc Zyngier
Emulating AT instructions is one the tasks devolved to the host hypervisor when NV is on. Here, we take the basic approach of emulating AT S1E{0,1}{R,W} using the AT instructions themselves. While this mostly work, it doesn't *always* work: - S1 page tables can be swapped out - shadow S2 can be incomplete and not contain mappings for the S1 page tables We are not trying to handle these case here, and defer it to a later patch. Suitable comments indicate where we are in dire need of better handling. Co-developed-by: Jintack Lim <jintack.lim@linaro.org> Signed-off-by: Jintack Lim <jintack.lim@linaro.org> Signed-off-by: Marc Zyngier <maz@kernel.org>