On 2013-03-14 13:19, Alexander Graf wrote: > > 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:ag...@suse.de] >>>>>>> Sent: Thursday, March 07, 2013 6:51 PM >>>>>>> To: Bhushan Bharat-R65777 >>>>>>> Cc: kvm-ppc@vger.kernel.org; k...@vger.kernel.org; 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.bhus...@freescale.com> >>>>>>>> --- >>>>>>>> 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?
Yes, the are meant for kvm_guest_debug.control on x86. I see that this is apparently different for ppc. Those bits you cited just control the general enabling of hard or soft BPs, not the activation of individual one. That is encoded into the BP registers on x86. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
