On 14.03.2013, at 13:13, Jan Kiszka wrote: > On 2013-03-14 13:09, Alexander Graf wrote: >> >> On 14.03.2013, at 12:57, Jan Kiszka wrote: >> >>> On 2013-03-14 12:54, Alexander Graf wrote: >>>> >>>> On 14.03.2013, at 05:42, Bhushan Bharat-R65777 wrote: >>>> >>>>> >>>>> >>>>>> -----Original Message----- >>>>>> From: Alexander Graf [mailto:agraf@xxxxxxx] >>>>>> Sent: Thursday, March 07, 2013 6:51 PM >>>>>> To: Bhushan Bharat-R65777 >>>>>> Cc: kvm-ppc@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; Wood Scott-B07421; Bhushan >>>>>> Bharat-R65777 >>>>>> Subject: Re: [PATCH 3/7] KVM: PPC: debug stub interface parameter defined >>>>>> >>>>>> >>>>>> On 28.02.2013, at 05:13, Bharat Bhushan wrote: >>>>>> >>>>>>> This patch defines the interface parameter for KVM_SET_GUEST_DEBUG >>>>>>> ioctl support. Follow up patches will use this for setting up hardware >>>>>>> breakpoints, watchpoints and software breakpoints. >>>>>>> >>>>>>> Also kvm_arch_vcpu_ioctl_set_guest_debug() is brought one level below. >>>>>>> This is because I am not sure what is required for book3s. So this >>>>>>> ioctl behaviour will not change for book3s. >>>>>>> >>>>>>> Signed-off-by: Bharat Bhushan <bharat.bhushan@xxxxxxxxxxxxx> >>>>>>> --- >>>>>>> arch/powerpc/include/uapi/asm/kvm.h | 23 +++++++++++++++++++++++ >>>>>>> arch/powerpc/kvm/book3s.c | 6 ++++++ >>>>>>> arch/powerpc/kvm/booke.c | 6 ++++++ >>>>>>> arch/powerpc/kvm/powerpc.c | 6 ------ >>>>>>> 4 files changed, 35 insertions(+), 6 deletions(-) >>>>>>> >>>>>>> diff --git a/arch/powerpc/include/uapi/asm/kvm.h >>>>>>> b/arch/powerpc/include/uapi/asm/kvm.h >>>>>>> index c2ff99c..15f9a00 100644 >>>>>>> --- a/arch/powerpc/include/uapi/asm/kvm.h >>>>>>> +++ b/arch/powerpc/include/uapi/asm/kvm.h >>>>>>> @@ -272,8 +272,31 @@ struct kvm_debug_exit_arch { >>>>>>> >>>>>>> /* for KVM_SET_GUEST_DEBUG */ >>>>>>> struct kvm_guest_debug_arch { >>>>>>> + struct { >>>>>>> + /* H/W breakpoint/watchpoint address */ >>>>>>> + __u64 addr; >>>>>>> + /* >>>>>>> + * Type denotes h/w breakpoint, read watchpoint, write >>>>>>> + * watchpoint or watchpoint (both read and write). >>>>>>> + */ >>>>>>> +#define KVMPPC_DEBUG_NOTYPE 0x0 >>>>>>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1) >>>>>>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2) >>>>>>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3) >>>>>>> + __u32 type; >>>>>>> + __u32 reserved; >>>>>>> + } bp[16]; >>>>>>> }; >>>>>>> >>>>>>> +/* Debug related defines */ >>>>>>> +/* >>>>>>> + * kvm_guest_debug->control is a 32 bit field. The lower 16 bits are >>>>>>> +generic >>>>>>> + * 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 >>>>>> >>>>>> You only need >>>>>> >>>>>> #define KVM_GUESTDBG_HW_BP 0x00010000 >>>>>> >>>>>> In absence of the flag, it's a SW breakpoint. >>>>> >>>>> We kept this for 2 reasons; 1) Same logic is applied for i386, so trying to keep consistent 2) better clarity. >>>> >>>> Jan, was there any special reason to have 2 flags for HW/SW breakpoint on x86 rather than one bit that indicates which one is used? >>> >>> Different mechanics on x86: HW goes via debug registers and shows up as >>> INT1, SW is INT3 (plus guest patching done by user land). >> >> Well, the same thing goes for us. What I'm asking is whether there is a specific reason (extensibility, oversight, taste, ...) that you did >> >> #define KVM_GUESTDBG_USE_SW_BP 0x00010000 >> #define KVM_GUESTDBG_USE_HW_BP 0x00020000 >> >> rather than >> >> #define KVM_GUESTDBG_BP_TYPE 0x00010000 >> #define KVM_GUESTDBG_BP_TYPE_SW 0x00010000 >> #define KVM_GUESTDBG_BP_TYPE_HW 0x00000000 >> >> :) > > Those bits enable or disable the features separately. You may also leave > both off if you like (and just use single stepping). Ah, so these are global configuration bits, not per-breakpoint configuration? Alex -- 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
