On 08/05/2015 11:23, Christoffer Dall wrote:
> On Wed, May 06, 2015 at 05:23:17PM +0100, Alex Bennée wrote:
>> Currently x86, powerpc and soon arm64 use the same two architecture
>> specific bits for guest debug support for software and hardware
>> breakpoints. This makes the shared values explicit while leaving the
>> gate open for another architecture to use some other value if they
>> really really want to.
>>
>> Signed-off-by: Alex Bennée <alex.bennee@xxxxxxxxxx>
>> Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
>>
>> diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
>> index ab4d473..1731569 100644
>> --- a/arch/powerpc/include/uapi/asm/kvm.h
>> +++ b/arch/powerpc/include/uapi/asm/kvm.h
>> @@ -310,8 +310,8 @@ struct kvm_guest_debug_arch {
>> * and upper 16 bits are architecture specific. Architecture specific defines
>> * that ioctl is for setting hardware breakpoint or software breakpoint.
>> */
>> -#define KVM_GUESTDBG_USE_SW_BP 0x00010000
>> -#define KVM_GUESTDBG_USE_HW_BP 0x00020000
>> +#define KVM_GUESTDBG_USE_SW_BP __KVM_GUESTDBG_USE_SW_BP
>> +#define KVM_GUESTDBG_USE_HW_BP __KVM_GUESTDBG_USE_HW_BP
>>
>> /* definition of registers in kvm_run */
>> struct kvm_sync_regs {
>> diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
>> index d7dcef5..1438202 100644
>> --- a/arch/x86/include/uapi/asm/kvm.h
>> +++ b/arch/x86/include/uapi/asm/kvm.h
>> @@ -250,8 +250,8 @@ struct kvm_debug_exit_arch {
>> __u64 dr7;
>> };
>>
>> -#define KVM_GUESTDBG_USE_SW_BP 0x00010000
>> -#define KVM_GUESTDBG_USE_HW_BP 0x00020000
>> +#define KVM_GUESTDBG_USE_SW_BP __KVM_GUESTDBG_USE_SW_BP
>> +#define KVM_GUESTDBG_USE_HW_BP __KVM_GUESTDBG_USE_HW_BP
>> #define KVM_GUESTDBG_INJECT_DB 0x00040000
>> #define KVM_GUESTDBG_INJECT_BP 0x00080000
>>
>> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
>> index 70ac641..3b6252e 100644
>> --- a/include/uapi/linux/kvm.h
>> +++ b/include/uapi/linux/kvm.h
>> @@ -570,8 +570,16 @@ struct kvm_s390_irq_state {
>>
>> /* for KVM_SET_GUEST_DEBUG */
>>
>> -#define KVM_GUESTDBG_ENABLE 0x00000001
>> -#define KVM_GUESTDBG_SINGLESTEP 0x00000002
>> +#define KVM_GUESTDBG_ENABLE (1 << 0)
>> +#define KVM_GUESTDBG_SINGLESTEP (1 << 1)
>> +
>> +/*
>> + * Architecture specific stuff uses the top 16 bits of the field,
>
> s/stuff/<something more specific>/
>
>> + * however there is some shared commonality for the common cases
>> + */
>> +#define __KVM_GUESTDBG_USE_SW_BP (1 << 16)
>> +#define __KVM_GUESTDBG_USE_HW_BP (1 << 17)
>> +
>>
>> struct kvm_guest_debug {
>> __u32 control;
>
> We sort of left this discussion hanging with me expressing slight
> concern about the usefulness about these defines.
>
> Paolo, what are your thoughts?
I would just lift these two KVM_GUESTDBG_* defines to
include/uapi/linux/kvm.h and say that architecture specific stuff uses
the top 14 bits of the field. :)
Paolo
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