Once upon a time, the KVM/arm64 world switch was a nice, clean, lean and mean piece of hand-crafted assembly code. Over time, features have crept in, the code has become harder to maintain, and the smallest change is a pain to introduce. The VHE patches are a prime example of why this doesn't work anymore.
This series rewrites most of the existing assembly code in C, but keeps the existing code structure in place (most function names will look familiar to the reader). The biggest change is that we don't have to deal with a static register allocation (the compiler does it for us), we can easily follow structure and pointers, and only the lowest level is still in assembly code. Oh, and a negative diffstat. There is still a healthy dose of inline assembly (system register accessors, runtime code patching), but I've tried not to make it too invasive. The generated code, while not exactly brilliant, doesn't look too shaby. I do expect a small performance degradation, but I believe this is something we can improve over time (my initial measurements don't show any obvious regression though). Assuming people are happy with the general approach taken here, I plan to rewrite the 32bit version in a similar vein, and reuse some parts of that code. Patches are against 4.4-rc4 (mostly), and I've pushed a branch out (kvm-arm64/wsinc). This has been tested on Juno, Seattle and the FVP model. I also have pushed out kvm-arm64/vhe-wsinc that implements VHE on top of these patches. * From v2: - Extensive review by Christoffer (thanks!) - Reuse the LR indexing macro used by the vgic-v3 layer - Plenty of comments added to the code * From v1: - A number of bugs have been squashed: vgic, FP/SIMD, debug, panic (thanks to Mark, Steve, Ard and Alex for their reviews) - Rebased on 4.4-rc2 plus KVM fixes aimed at -rc3 plus a couple of gic-v3 fixes Marc Zyngier (21): arm64: KVM: Add a HYP-specific header file arm64: KVM: Implement vgic-v2 save/restore KVM: arm/arm64: vgic-v3: Make the LR indexing macro public arm64: KVM: Implement vgic-v3 save/restore arm64: KVM: Implement timer save/restore arm64: KVM: Implement system register save/restore arm64: KVM: Implement 32bit system register save/restore arm64: KVM: Implement debug save/restore arm64: KVM: Implement guest entry arm64: KVM: Add patchable function selector arm64: KVM: Implement the core world switch arm64: KVM: Implement fpsimd save/restore arm64: KVM: Implement TLB handling arm64: KVM: HYP mode entry points arm64: KVM: Add panic handling arm64: KVM: Add compatibility aliases arm64: KVM: Map the kernel RO section into HYP arm64: KVM: Move away from the assembly version of the world switch arm64: KVM: Turn system register numbers to an enum arm64: KVM: Cleanup asm-offset.c arm64: KVM: Remove weak attributes Mark Rutland (1): arm64: Add macros to read/write system registers arch/arm/kvm/arm.c | 7 + arch/arm64/include/asm/kvm_asm.h | 76 --- arch/arm64/include/asm/kvm_emulate.h | 1 - arch/arm64/include/asm/kvm_host.h | 81 ++- arch/arm64/include/asm/kvm_mmio.h | 1 - arch/arm64/include/asm/sysreg.h | 17 + arch/arm64/kernel/asm-offsets.c | 40 +- arch/arm64/kvm/Makefile | 3 +- arch/arm64/kvm/guest.c | 1 - arch/arm64/kvm/handle_exit.c | 1 + arch/arm64/kvm/hyp.S | 1081 +--------------------------------- arch/arm64/kvm/hyp/Makefile | 14 + arch/arm64/kvm/hyp/debug-sr.c | 140 +++++ arch/arm64/kvm/hyp/entry.S | 161 +++++ arch/arm64/kvm/hyp/fpsimd.S | 33 ++ arch/arm64/kvm/hyp/hyp-entry.S | 212 +++++++ arch/arm64/kvm/hyp/hyp.h | 90 +++ arch/arm64/kvm/hyp/switch.c | 175 ++++++ arch/arm64/kvm/hyp/sysreg-sr.c | 138 +++++ arch/arm64/kvm/hyp/timer-sr.c | 72 +++ arch/arm64/kvm/hyp/tlb.c | 80 +++ arch/arm64/kvm/hyp/vgic-v2-sr.c | 84 +++ arch/arm64/kvm/hyp/vgic-v3-sr.c | 228 +++++++ arch/arm64/kvm/sys_regs.c | 1 + arch/arm64/kvm/vgic-v2-switch.S | 134 ----- arch/arm64/kvm/vgic-v3-switch.S | 269 --------- include/clocksource/arm_arch_timer.h | 6 + include/kvm/arm_vgic.h | 6 + virt/kvm/arm/vgic-v3.c | 11 +- 29 files changed, 1551 insertions(+), 1612 deletions(-) create mode 100644 arch/arm64/kvm/hyp/Makefile create mode 100644 arch/arm64/kvm/hyp/debug-sr.c create mode 100644 arch/arm64/kvm/hyp/entry.S create mode 100644 arch/arm64/kvm/hyp/fpsimd.S create mode 100644 arch/arm64/kvm/hyp/hyp-entry.S create mode 100644 arch/arm64/kvm/hyp/hyp.h create mode 100644 arch/arm64/kvm/hyp/switch.c create mode 100644 arch/arm64/kvm/hyp/sysreg-sr.c create mode 100644 arch/arm64/kvm/hyp/timer-sr.c create mode 100644 arch/arm64/kvm/hyp/tlb.c create mode 100644 arch/arm64/kvm/hyp/vgic-v2-sr.c create mode 100644 arch/arm64/kvm/hyp/vgic-v3-sr.c delete mode 100644 arch/arm64/kvm/vgic-v2-switch.S delete mode 100644 arch/arm64/kvm/vgic-v3-switch.S -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html