This patch series adds debug support, a key feature missing from the KVM/arm64 port. The main idea is to keep track of whether the debug registers are "dirty" (changed by the guest) or not. In this case, perform the usual save/restore dance, for one run only. It means we only have a penalty if a guest is actively using the debug registers. The amount of registers is properly frightening, but CPUs actually only implement a subset of them. Also, there is a number of registers we don't bother emulating (things having to do with external debug and OSlock). External debug is when you actually plug a physical JTAG into the CPU. OSlock is a way to prevent "other software" to play with the debug registers. My understanding is that it is only useful in combination with the external debug. In both case, implementing support for this is probably not worth the effort, at least for the time being. This has been tested on a Cortex-A53/A57 platform, running both 32 and 64bit guests, on top of 3.16-rc1. This code also lives in my tree in the kvm-arm/debug-merge-3.17 branch (containing GICv3 and BE patches), which I consider to be a stable branch, ready to be merged. >From v3 [3]: - Clearer comments about the way we deal with the dirty bit - Additional comment about future use of the per-vcpu debug flags - Added missing Reviewed-by tags - Rebased on top of the branch from hell (GICv3+BE) >From v2 [2]: - Fixed a number of very stupid bugs in the macros generating the trap entries - Added some documentation explaining why we don't bother emulating external debug and the OSlock stuff - Other bits of documentation here and there >From v1 [1]: - Renamed trap_wi_raz to trap_raz_wi - Renamed skip_clean_debug_state to skip_debug_state - Simplified debug state computing, moved to its own macro - Added some comment to make the logic more obvious [1]: https://lists.cs.columbia.edu/pipermail/kvmarm/2014-May/009332.html [2]: https://lists.cs.columbia.edu/pipermail/kvmarm/2014-May/009534.html [3]: https://lists.cs.columbia.edu/pipermail/kvmarm/2014-June/010124.html Marc Zyngier (9): arm64: KVM: rename pm_fake handler to trap_raz_wi arm64: move DBG_MDSCR_* to asm/debug-monitors.h arm64: KVM: add trap handlers for AArch64 debug registers arm64: KVM: common infrastructure for handling AArch32 CP14/CP15 arm64: KVM: use separate tables for AArch32 32 and 64bit traps arm64: KVM: check ordering of all system register tables arm64: KVM: add trap handlers for AArch32 debug registers arm64: KVM: implement lazy world switch for debug registers arm64: KVM: enable trapping of all debug registers arch/arm64/include/asm/debug-monitors.h | 19 +- arch/arm64/include/asm/kvm_asm.h | 39 ++- arch/arm64/include/asm/kvm_coproc.h | 3 +- arch/arm64/include/asm/kvm_host.h | 16 +- arch/arm64/kernel/asm-offsets.c | 1 + arch/arm64/kernel/debug-monitors.c | 9 - arch/arm64/kvm/handle_exit.c | 4 +- arch/arm64/kvm/hyp.S | 471 +++++++++++++++++++++++++++- arch/arm64/kvm/sys_regs.c | 533 ++++++++++++++++++++++++++++---- 9 files changed, 994 insertions(+), 101 deletions(-) -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
