Hi, KVM nVHE hyp code runs under different VA mapping than the kernel, which meant that .hyp.text code had to use PC-relative addressing because relocations would produce a kernel VA. Programmers had to be extremely careful with C semantics to not break this fragile setup. See hyp_symbol_addr comments for details. Now that we're moving to all nVHE hyp code/data being in separate ELF sections from the rest of the kernel, it is becoming possible to revisit relocations during early boot, filter those used by nVHE hyp and converting those (already relocated) kern VAs to hyp VAs. Sending this as an RFC, mainly to get feedback but also because it's only lightly tested. It still feels hacky but much more robust than the existing approach. The one place where I see somebody breaking this is the list of ELF sections owned by ELF. That list is currently evolving but should stabilize over time. The patches are based on kvmarm/queue (with Marc's "Host EL2 entry improvements") and my "Opt-in always-on nVHE hypervisor" v2 series. -David David Brazdil (6): kvm: arm64: Set up .hyp.rodata ELF section kvm: arm64: Fix up RELA relocations in hyp code/data kvm: arm64: Fix up RELR relocation in hyp code/data kvm: arm64: Remove patching of fn pointers in hyp kvm: arm64: Fix constant-pool users in hyp kvm: arm64: Remove hyp_symbol_addr arch/arm64/include/asm/kvm_asm.h | 20 ---- arch/arm64/include/asm/kvm_mmu.h | 48 ++++----- arch/arm64/include/asm/sections.h | 2 +- arch/arm64/kernel/image-vars.h | 1 - arch/arm64/kernel/smp.c | 4 +- arch/arm64/kernel/vmlinux.lds.S | 7 +- arch/arm64/kvm/arm.c | 7 +- arch/arm64/kvm/hyp/include/hyp/switch.h | 4 +- arch/arm64/kvm/hyp/nvhe/host.S | 29 +++--- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 11 +- arch/arm64/kvm/hyp/nvhe/hyp-smp.c | 4 +- arch/arm64/kvm/hyp/nvhe/hyp.lds.S | 1 + arch/arm64/kvm/hyp/nvhe/psci-relay.c | 4 +- arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c | 2 +- arch/arm64/kvm/va_layout.c | 123 +++++++++++++++++++++-- 15 files changed, 175 insertions(+), 92 deletions(-) -- 2.29.2.299.gdc1121823c-goog _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
