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2025-06-26KVM: arm64: nv: Fix MI line level calculation in vgic_v3_nested_update_mi()Wei-Lin Chang
The state of the vcpu's MI line should be asserted when its ICH_HCR_EL2.En is set and ICH_MISR_EL2 is non-zero. Using bitwise AND (&=) directly for this calculation will not give us the correct result when the LSB of the vcpu's ICH_MISR_EL2 isn't set. Correct this by directly computing the line level with a logical AND operation. Signed-off-by: Wei-Lin Chang <r09922117@csie.ntu.edu.tw> Link: https://lore.kernel.org/r/20250625084709.3968844-1-r09922117@csie.ntu.edu.tw [maz: drop the level check from the original code] Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-06-19KVM: arm64: nv: Fix tracking of shadow list registersMarc Zyngier
Wei-Lin reports that the tracking of shadow list registers is majorly broken when resync'ing the L2 state after a run, as we confuse the guest's LR index with the host's, potentially losing the interrupt state. While this could be fixed by adding yet another side index to track it (Wei-Lin's fix), it may be better to refactor this code to avoid having a side index altogether, limiting the risk to introduce this class of bugs. A key observation is that the shadow index is always the number of bits in the lr_map bitmap. With that, the parallel indexing scheme can be completely dropped. While doing this, introduce a couple of helpers that abstract the index conversion and some of the LR repainting, making the whole exercise much simpler. Reported-by: Wei-Lin Chang <r09922117@csie.ntu.edu.tw> Reviewed-by: Wei-Lin Chang <r09922117@csie.ntu.edu.tw> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20250614145721.2504524-1-r09922117@csie.ntu.edu.tw Link: https://lore.kernel.org/r/86qzzkc5xa.wl-maz@kernel.org
2025-06-05KVM: arm64: Add assignment-specific sysreg accessorMarc Zyngier
Assigning a value to a system register doesn't do what it is supposed to be doing if that register is one that has RESx bits. The main problem is that we use __vcpu_sys_reg(), which can be used both as a lvalue and rvalue. When used as a lvalue, the bit masking occurs *before* the new value is assigned, meaning that we (1) do pointless work on the old cvalue, and (2) potentially assign an invalid value as we fail to apply the masks to it. Fix this by providing a new __vcpu_assign_sys_reg() that does what it says on the tin, and sanitises the *new* value instead of the old one. This comes with a significant amount of churn. Reviewed-by: Miguel Luis <miguel.luis@oracle.com> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20250603070824.1192795-2-maz@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-16KVM: arm64: nv: Remove clearing of ICH_LR<n>.EOI if ICH_LR<n>.HW == 1Wei-Lin Chang
In the case of ICH_LR<n>.HW == 1, bit 41 of LR is just a part of pINTID without EOI meaning, and bit 41 will be zeroed by the subsequent clearing of ICH_LR_PHYS_ID_MASK anyway. No functional changes intended. Signed-off-by: Wei-Lin Chang <r09922117@csie.ntu.edu.tw> Link: https://lore.kernel.org/r/20250512133223.866999-1-r09922117@csie.ntu.edu.tw Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-03-03KVM: arm64: nv: Fold GICv3 host trapping requirements into guest setupMarc Zyngier
Popular HW that is able to use NV also has a broken vgic implementation that requires trapping. On such HW, propagate the host trap bits into the guest's shadow ICH_HCR_EL2 register, making sure we don't allow an L2 guest to bring the system down. This involves a bit of tweaking so that the emulation code correctly poicks up the shadow state as needed, and to only partially sync ICH_HCR_EL2 back with the guest state to capture EOIcount. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20250225172930.1850838-15-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-03-03KVM: arm64: nv: Propagate used_lrs between L1 and L0 contextsMarc Zyngier
We have so far made sure that L1 and L0 vgic contexts were totally independent. There is however one spot of bother with this approach, and that's in the GICv3 emulation code required by our fruity friends. The issue is that the emulation code needs to know how many LRs are in flight. And while it is easy to reach the L0 version through the vcpu pointer, doing so for the L1 is much more complicated, as these structures are private to the nested code. We could simply expose that structure and pick one or the other depending on the context, but this seems extra complexity for not much benefit. Instead, just propagate the number of used LRs from the nested code into the L0 context, and be done with it. Should this become a burden, it can be easily rectified. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20250225172930.1850838-14-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-03-03KVM: arm64: nv: Add Maintenance Interrupt emulationMarc Zyngier
Emulating the vGIC means emulating the dreaded Maintenance Interrupt. This is a two-pronged problem: - while running L2, getting an MI translates into an MI injected in the L1 based on the state of the HW. - while running L1, we must accurately reflect the state of the MI line, based on the in-memory state. The MI INTID is added to the distributor, as expected on any virtualisation-capable implementation, and further patches will allow its configuration. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20250225172930.1850838-11-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-03-03KVM: arm64: nv: Nested GICv3 emulationMarc Zyngier
When entering a nested VM, we set up the hypervisor control interface based on what the guest hypervisor has set. Especially, we investigate each list register written by the guest hypervisor whether HW bit is set. If so, we translate hw irq number from the guest's point of view to the real hardware irq number if there is a mapping. Co-developed-by: Jintack Lim <jintack@cs.columbia.edu> Signed-off-by: Jintack Lim <jintack@cs.columbia.edu> [Christoffer: Redesigned execution flow around vcpu load/put] Co-developed-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com> [maz: Rewritten to support GICv3 instead of GICv2, NV2 support] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20250225172930.1850838-9-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-03-03KVM: arm64: nv: Plumb handling of GICv3 EL2 accessesMarc Zyngier
Wire the handling of all GICv3 EL2 registers, and provide emulation for all the non memory-backed registers (ICC_SRE_EL2, ICH_VTR_EL2, ICH_MISR_EL2, ICH_ELRSR_EL2, and ICH_EISR_EL2). Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20250225172930.1850838-7-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>