Alex Bennée <alex.bennee@xxxxxxxxxx> writes: <snip> > Alex Bennée <alex.bennee@xxxxxxxxxx> writes: > >> Hi, >> >> I've almost finished the ARMv8 guest debug support but I have one >> problem left to solve. userspace needs to know how many hardware debug >> registers are available for GDB to use. This information is available >> from the ID_AA64DFR0_EL1 register. <Snip> >> So far the options I've examined are: >> >> * KVM ioctl GET_ONE_REG(ID_AA64DFR0_EL1) >> * ptrace(PTRACE_GETREGSET, NT_ARM_HW_WATCH) >> * KVM ioctl KVM_GET_DEBUGREGS >> * Export the information via sysfs >> * Expand /proc/cpuinfo >> * Add another KVM ioctl? Alexander Graf pointed out that KVM_CHECK_EXTENSION can return any positive number for success. How about using: max_hw_bps = kvm_check_extension(kvm_state, KVM_CAP_GUEST_DEBUG_HW_BPS); max_hw_wps = kvm_check_extension(kvm_state, KVM_CAP_GUEST_DEBUG_HW_WPS); Seems pretty sane, doesn't change the semantics of an API and is architecture agnostic if others need the number? -- Alex Bennée -- 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
