This patch series adds debug support, a key feature missing from the KVM/armv7 port. The main idea is borrowed from armv8, which 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-A15 platform, running 32bit guests. The patches for this series are based off v4.1-rc5 and can be found at: https://git.linaro.org/people/zhichao.huang/linux.git branch: guest-debug/4.1-rc5-v2 >From v1 [1]: - Added missing cp14 reset functions - Disable debug mode if we don't need it to reduce unnecessary switch [1]: https://lists.cs.columbia.edu/pipermail/kvmarm/2015-May/014729.html Zhichao Huang (11): KVM: arm: plug guest debug exploit KVM: arm: rename pm_fake handler to trap_raz_wi KVM: arm: enable to use the ARM_DSCR_MDBGEN macro from KVM assembly code KVM: arm: common infrastructure for handling AArch32 CP14/CP15 KVM: arm: check ordering of all system register tables KVM: arm: add trap handlers for 32-bit debug registers KVM: arm: add trap handlers for 64-bit debug registers KVM: arm: implement dirty bit mechanism for debug registers KVM: arm: disable debug mode if we don't actually need it. KVM: arm: implement lazy world switch for debug registers KVM: arm: enable trapping of all debug registers arch/arm/include/asm/hw_breakpoint.h | 54 ++--- arch/arm/include/asm/kvm_asm.h | 15 ++ arch/arm/include/asm/kvm_coproc.h | 3 +- arch/arm/include/asm/kvm_host.h | 6 + arch/arm/kernel/asm-offsets.c | 2 + arch/arm/kernel/hw_breakpoint.c | 55 ++++- arch/arm/kvm/coproc.c | 386 +++++++++++++++++++++++++++++------ arch/arm/kvm/handle_exit.c | 4 +- arch/arm/kvm/interrupts.S | 16 ++ arch/arm/kvm/interrupts_head.S | 313 +++++++++++++++++++++++++++- 10 files changed, 757 insertions(+), 97 deletions(-) -- 1.7.12.4 -- 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
