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Commit 6398da13 authored by James Hogan's avatar James Hogan Committed by Paolo Bonzini
Browse files

MIPS: KVM: Trace guest register access emulation 



Trace emulation of guest access to various registers via
MFC0/MTC0/DMFC0/DMTC0 instructions (coprocessor 0) and the RDHWR
instruction (hardware registers exposed to userland), replacing some
existing kvm_debug calls. Trace events are much more practical for this
kind of debug output.

Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 93258604

arch/mips/kvm/emulate.c

+19 −12
Original line number Diff line number Diff line
@@ -979,7 +979,6 @@ enum emulation_result kvm_mips_emulate_CP0(u32 inst, u32 *opc, u32 cause, 
	struct mips_coproc *cop0 = vcpu->arch.cop0;

	enum emulation_result er = EMULATE_DONE;

	u32 rt, rd, copz, sel, co_bit, op;

	unsigned long pc = vcpu->arch.pc;

	unsigned long curr_pc;



	/*
@@ -1046,20 +1045,27 @@ enum emulation_result kvm_mips_emulate_CP0(u32 inst, u32 *opc, u32 cause, 
#endif

			}



			kvm_debug

			    ("[%#lx] MFCz[%d][%d], vcpu->arch.gprs[%d]: %#lx\n",

			     pc, rd, sel, rt, vcpu->arch.gprs[rt]);



			trace_kvm_hwr(vcpu, KVM_TRACE_MFC0,

				      KVM_TRACE_COP0(rd, sel),

				      vcpu->arch.gprs[rt]);

			break;



		case dmfc_op:

			vcpu->arch.gprs[rt] = cop0->reg[rd][sel];



			trace_kvm_hwr(vcpu, KVM_TRACE_DMFC0,

				      KVM_TRACE_COP0(rd, sel),

				      vcpu->arch.gprs[rt]);

			break;



		case mtc_op:

#ifdef CONFIG_KVM_MIPS_DEBUG_COP0_COUNTERS

			cop0->stat[rd][sel]++;

#endif

			trace_kvm_hwr(vcpu, KVM_TRACE_MTC0,

				      KVM_TRACE_COP0(rd, sel),

				      vcpu->arch.gprs[rt]);



			if ((rd == MIPS_CP0_TLB_INDEX)

			    && (vcpu->arch.gprs[rt] >=

				KVM_MIPS_GUEST_TLB_SIZE)) {
@@ -1098,10 +1104,6 @@ enum emulation_result kvm_mips_emulate_CP0(u32 inst, u32 *opc, u32 cause, 
				kvm_mips_write_count(vcpu, vcpu->arch.gprs[rt]);

				goto done;

			} else if ((rd == MIPS_CP0_COMPARE) && (sel == 0)) {

				kvm_debug("[%#lx] MTCz, COMPARE %#lx <- %#lx\n",

					  pc, kvm_read_c0_guest_compare(cop0),

					  vcpu->arch.gprs[rt]);



				/* If we are writing to COMPARE */

				/* Clear pending timer interrupt, if any */

				kvm_mips_write_compare(vcpu,
@@ -1237,14 +1239,14 @@ enum emulation_result kvm_mips_emulate_CP0(u32 inst, u32 *opc, u32 cause, 
				kvm_mips_trans_mtc0(inst, opc, vcpu);

#endif

			}



			kvm_debug("[%#lx] MTCz, cop0->reg[%d][%d]: %#lx\n", pc,

				  rd, sel, cop0->reg[rd][sel]);

			break;



		case dmtc_op:

			kvm_err("!!!!!!![%#lx]dmtc_op: rt: %d, rd: %d, sel: %d!!!!!!\n",

				vcpu->arch.pc, rt, rd, sel);

			trace_kvm_hwr(vcpu, KVM_TRACE_DMTC0,

				      KVM_TRACE_COP0(rd, sel),

				      vcpu->arch.gprs[rt]);

			er = EMULATE_FAIL;

			break;
@@ -2307,6 +2309,8 @@ enum emulation_result kvm_mips_handle_ri(u32 cause, u32 *opc, 
		int usermode = !KVM_GUEST_KERNEL_MODE(vcpu);

		int rd = (inst & RD) >> 11;

		int rt = (inst & RT) >> 16;

		int sel = (inst >> 6) & 0x7;



		/* If usermode, check RDHWR rd is allowed by guest HWREna */

		if (usermode && !(kvm_read_c0_guest_hwrena(cop0) & BIT(rd))) {

			kvm_debug("RDHWR %#x disallowed by HWREna @ %p\n",
@@ -2342,6 +2346,9 @@ enum emulation_result kvm_mips_handle_ri(u32 cause, u32 *opc, 
			kvm_debug("RDHWR %#x not supported @ %p\n", rd, opc);

			goto emulate_ri;

		}



		trace_kvm_hwr(vcpu, KVM_TRACE_RDHWR, KVM_TRACE_HWR(rd, sel),

			      vcpu->arch.gprs[rt]);

	} else {

		kvm_debug("Emulate RI not supported @ %p: %#x\n", opc, inst);

		goto emulate_ri;

arch/mips/kvm/trace.h

+88 −0
Original line number Diff line number Diff line
@@ -124,6 +124,94 @@ TRACE_EVENT(kvm_exit, 
		      __entry->pc)

);



#define KVM_TRACE_MFC0		0

#define KVM_TRACE_MTC0		1

#define KVM_TRACE_DMFC0		2

#define KVM_TRACE_DMTC0		3

#define KVM_TRACE_RDHWR		4



#define KVM_TRACE_HWR_COP0	0

#define KVM_TRACE_HWR_HWR	1



#define KVM_TRACE_COP0(REG, SEL)	((KVM_TRACE_HWR_COP0 << 8) |	\

					 ((REG) << 3) | (SEL))

#define KVM_TRACE_HWR(REG, SEL)		((KVM_TRACE_HWR_HWR  << 8) |	\

					 ((REG) << 3) | (SEL))



#define kvm_trace_symbol_hwr_ops				\

	{ KVM_TRACE_MFC0,		"MFC0" },		\

	{ KVM_TRACE_MTC0,		"MTC0" },		\

	{ KVM_TRACE_DMFC0,		"DMFC0" },		\

	{ KVM_TRACE_DMTC0,		"DMTC0" },		\

	{ KVM_TRACE_RDHWR,		"RDHWR" }



#define kvm_trace_symbol_hwr_cop				\

	{ KVM_TRACE_HWR_COP0,		"COP0" },		\

	{ KVM_TRACE_HWR_HWR,		"HWR" }



#define kvm_trace_symbol_hwr_regs				\

	{ KVM_TRACE_COP0( 0, 0),	"Index" },		\

	{ KVM_TRACE_COP0( 2, 0),	"EntryLo0" },		\

	{ KVM_TRACE_COP0( 3, 0),	"EntryLo1" },		\

	{ KVM_TRACE_COP0( 4, 0),	"Context" },		\

	{ KVM_TRACE_COP0( 4, 2),	"UserLocal" },		\

	{ KVM_TRACE_COP0( 5, 0),	"PageMask" },		\

	{ KVM_TRACE_COP0( 6, 0),	"Wired" },		\

	{ KVM_TRACE_COP0( 7, 0),	"HWREna" },		\

	{ KVM_TRACE_COP0( 8, 0),	"BadVAddr" },		\

	{ KVM_TRACE_COP0( 9, 0),	"Count" },		\

	{ KVM_TRACE_COP0(10, 0),	"EntryHi" },		\

	{ KVM_TRACE_COP0(11, 0),	"Compare" },		\

	{ KVM_TRACE_COP0(12, 0),	"Status" },		\

	{ KVM_TRACE_COP0(12, 1),	"IntCtl" },		\

	{ KVM_TRACE_COP0(12, 2),	"SRSCtl" },		\

	{ KVM_TRACE_COP0(13, 0),	"Cause" },		\

	{ KVM_TRACE_COP0(14, 0),	"EPC" },		\

	{ KVM_TRACE_COP0(15, 0),	"PRId" },		\

	{ KVM_TRACE_COP0(15, 1),	"EBase" },		\

	{ KVM_TRACE_COP0(16, 0),	"Config" },		\

	{ KVM_TRACE_COP0(16, 1),	"Config1" },		\

	{ KVM_TRACE_COP0(16, 2),	"Config2" },		\

	{ KVM_TRACE_COP0(16, 3),	"Config3" },		\

	{ KVM_TRACE_COP0(16, 4),	"Config4" },		\

	{ KVM_TRACE_COP0(16, 5),	"Config5" },		\

	{ KVM_TRACE_COP0(16, 7),	"Config7" },		\

	{ KVM_TRACE_COP0(26, 0),	"ECC" },		\

	{ KVM_TRACE_COP0(30, 0),	"ErrorEPC" },		\

	{ KVM_TRACE_HWR( 0, 0),		"CPUNum" },		\

	{ KVM_TRACE_HWR( 1, 0),		"SYNCI_Step" },		\

	{ KVM_TRACE_HWR( 2, 0),		"CC" },			\

	{ KVM_TRACE_HWR( 3, 0),		"CCRes" },		\

	{ KVM_TRACE_HWR(29, 0),		"ULR" }



TRACE_EVENT(kvm_hwr,

	    TP_PROTO(struct kvm_vcpu *vcpu, unsigned int op, unsigned int reg,

		     unsigned long val),

	    TP_ARGS(vcpu, op, reg, val),

	    TP_STRUCT__entry(

			__field(unsigned long, val)

			__field(u16, reg)

			__field(u8, op)

	    ),



	    TP_fast_assign(

			__entry->val = val;

			__entry->reg = reg;

			__entry->op = op;

	    ),



	    TP_printk("%s %s (%s:%u:%u) 0x%08lx",

		      __print_symbolic(__entry->op,

				       kvm_trace_symbol_hwr_ops),

		      __print_symbolic(__entry->reg,

				       kvm_trace_symbol_hwr_regs),

		      __print_symbolic(__entry->reg >> 8,

				       kvm_trace_symbol_hwr_cop),

		      (__entry->reg >> 3) & 0x1f,

		      __entry->reg & 0x7,

		      __entry->val)

);



#define KVM_TRACE_AUX_RESTORE		0

#define KVM_TRACE_AUX_SAVE		1

#define KVM_TRACE_AUX_ENABLE		2