> -----Original Message-----
> From: tiejun.chen [mailto:tiejun.c...@windriver.com]
> Sent: Wednesday, June 26, 2013 12:25 PM
> To: Bhushan Bharat-R65777
> Cc: kvm-...@vger.kernel.org; k...@vger.kernel.org; ag...@suse.de; Wood Scott-
> B07421; b...@kernel.crashing.org; linuxppc-dev@lists.ozlabs.org; linux-
> ker...@vger.kernel.org; mi...@neuling.org; Bhushan Bharat-R65777
> Subject: Re: [PATCH 4/6 v5] KVM: PPC: exit to user space on "ehpriv"
> instruction
>
> On 06/26/2013 01:42 PM, Bharat Bhushan wrote:
> > "ehpriv" instruction is used for setting software breakpoints
> > by user space. This patch adds support to exit to user space
> > with "run->debug" have relevant information.
> >
> > As this is the first point we are using run->debug, also defined
> > the run->debug structure.
> >
> > Signed-off-by: Bharat Bhushan <bharat.bhus...@freescale.com>
> > ---
> > arch/powerpc/include/asm/disassemble.h | 4 ++++
> > arch/powerpc/include/uapi/asm/kvm.h | 21 +++++++++++++++++----
> > arch/powerpc/kvm/e500_emulate.c | 27 +++++++++++++++++++++++++++
> > 3 files changed, 48 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/disassemble.h
> b/arch/powerpc/include/asm/disassemble.h
> > index 9b198d1..856f8de 100644
> > --- a/arch/powerpc/include/asm/disassemble.h
> > +++ b/arch/powerpc/include/asm/disassemble.h
> > @@ -77,4 +77,8 @@ static inline unsigned int get_d(u32 inst)
> > return inst & 0xffff;
> > }
> >
> > +static inline unsigned int get_oc(u32 inst)
> > +{
> > + return (inst >> 11) & 0x7fff;
> > +}
> > #endif /* __ASM_PPC_DISASSEMBLE_H__ */
> > diff --git a/arch/powerpc/include/uapi/asm/kvm.h
> b/arch/powerpc/include/uapi/asm/kvm.h
> > index 0fb1a6e..ded0607 100644
> > --- a/arch/powerpc/include/uapi/asm/kvm.h
> > +++ b/arch/powerpc/include/uapi/asm/kvm.h
> > @@ -269,7 +269,24 @@ struct kvm_fpu {
> > __u64 fpr[32];
> > };
> >
> > +/*
> > + * Defines for h/w breakpoint, watchpoint (read, write or both) and
> > + * software breakpoint.
> > + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
> > + * for KVM_DEBUG_EXIT.
> > + */
> > +#define KVMPPC_DEBUG_NONE 0x0
> > +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
> > +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
> > +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
> > struct kvm_debug_exit_arch {
> > + __u64 address;
> > + /*
> > + * exiting to userspace because of h/w breakpoint, watchpoint
> > + * (read, write or both) and software breakpoint.
> > + */
> > + __u32 status;
> > + __u32 reserved;
> > };
> >
> > /* for KVM_SET_GUEST_DEBUG */
> > @@ -281,10 +298,6 @@ struct kvm_guest_debug_arch {
> > * Type denotes h/w breakpoint, read watchpoint, write
> > * watchpoint or watchpoint (both read and write).
> > */
> > -#define KVMPPC_DEBUG_NONE 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];
> > diff --git a/arch/powerpc/kvm/e500_emulate.c
> > b/arch/powerpc/kvm/e500_emulate.c
> > index b10a012..dab9d07 100644
> > --- a/arch/powerpc/kvm/e500_emulate.c
> > +++ b/arch/powerpc/kvm/e500_emulate.c
> > @@ -26,6 +26,8 @@
> > #define XOP_TLBRE 946
> > #define XOP_TLBWE 978
> > #define XOP_TLBILX 18
> > +#define XOP_EHPRIV 270
> > +#define EHPRIV_OC_DEBUG 0
>
> As I think the case, "OC = 0", is a bit specific since IIRC, if the OC
> operand is omitted, its equal 0 by default. So I think we should start this OC
> value from 1 or other magic number.
ehpriv instruction is defined to be used as:
ehpriv OC // where OC can be 0,1, ... n
and in extended for it can be used as
ehpriv // With no OC, and here it assumes OC = 0
So OC = 0 is not specific but "ehpriv" is same as "ehpriv 0".
I do not think of any special reason to reserve "ehpriv" and "ehpriv 0".
Thanks
-Bharat
>
> And if possible, we'd better add some comments to describe this to make the OC
> definition readable.
>
> Tiejun
>
> >
> > #ifdef CONFIG_KVM_E500MC
> > static int dbell2prio(ulong param)
> > @@ -82,6 +84,26 @@ static int kvmppc_e500_emul_msgsnd(struct kvm_vcpu *vcpu,
> int rb)
> > }
> > #endif
> >
> > +static int kvmppc_e500_emul_ehpriv(struct kvm_run *run, struct kvm_vcpu
> *vcpu,
> > + unsigned int inst, int *advance)
> > +{
> > + int emulated = EMULATE_DONE;
> > +
> > + switch (get_oc(inst)) {
> > + case EHPRIV_OC_DEBUG:
> > + run->exit_reason = KVM_EXIT_DEBUG;
> > + run->debug.arch.address = vcpu->arch.pc;
> > + run->debug.arch.status = 0;
> > + kvmppc_account_exit(vcpu, DEBUG_EXITS);
> > + emulated = EMULATE_EXIT_USER;
> > + *advance = 0;
> > + break;
> > + default:
> > + emulated = EMULATE_FAIL;
> > + }
> > + return emulated;
> > +}
> > +
> > int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
> > unsigned int inst, int *advance)
> > {
> > @@ -130,6 +152,11 @@ int kvmppc_core_emulate_op(struct kvm_run *run, struct
> kvm_vcpu *vcpu,
> > emulated = kvmppc_e500_emul_tlbivax(vcpu, ea);
> > break;
> >
> > + case XOP_EHPRIV:
> > + emulated = kvmppc_e500_emul_ehpriv(run, vcpu, inst,
> > + advance);
> > + break;
> > +
> > default:
> > emulated = EMULATE_FAIL;
> > }
> >
>
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