[PATCH] KVM: PPC: exit to user space on "ehpriv" instruction

Bharat Bhushan
2013-05-07T09:52:51Z

"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.bhushan@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

#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;
}
--
1.5.6.5