[PATCH 16/32] KVM: MIPS: Add guest exit exception callback

From: James Hogan <james.hogan@imgtec.com>
To: <linux-mips@linux-mips.org>, <kvm@vger.kernel.org>
Cc: "James Hogan" <james.hogan@imgtec.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Ralf Baechle" <ralf@linux-mips.org>,
	"Steven Rostedt" <rostedt@goodmis.org>,
	"Ingo Molnar" <mingo@redhat.com>
Subject: [PATCH 16/32] KVM: MIPS: Add guest exit exception callback
Date: Thu, 2 Mar 2017 09:36:43 +0000	[thread overview]
Message-ID: <dbd9d1313c2d076f9536c59694fe1bc3a6757d53.1488447004.git-series.james.hogan@imgtec.com> (raw)
In-Reply-To: <cover.5cfb5298ebc2f5308f4f56aaac7fa31c39a8ab58.1488447004.git-series.james.hogan@imgtec.com>

Add a callback for MIPS KVM implementations to handle the VZ guest
exit exception. Currently the trap & emulate implementation contains a
stub which reports an internal error, but the callback will be used
properly by the VZ implementation.

Signed-off-by: James 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
---
 arch/mips/include/asm/kvm_host.h |  1 +
 arch/mips/kvm/mips.c             |  5 +++++
 arch/mips/kvm/trace.h            |  2 ++
 arch/mips/kvm/trap_emul.c        | 24 ++++++++++++++++++++++++
 4 files changed, 32 insertions(+), 0 deletions(-)

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 8572f024f728..3fee98e44f67 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -545,6 +545,7 @@ struct kvm_mips_callbacks {
 	int (*handle_msa_fpe)(struct kvm_vcpu *vcpu);
 	int (*handle_fpe)(struct kvm_vcpu *vcpu);
 	int (*handle_msa_disabled)(struct kvm_vcpu *vcpu);
+	int (*handle_guest_exit)(struct kvm_vcpu *vcpu);
 	int (*hardware_enable)(void);
 	void (*hardware_disable)(void);
 	int (*check_extension)(struct kvm *kvm, long ext);
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 59e79ca76720..9dd9905681ed 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -1350,6 +1350,11 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
 		ret = kvm_mips_callbacks->handle_msa_disabled(vcpu);
 		break;
 
+	case EXCCODE_GE:
+		/* defer exit accounting to handler */
+		ret = kvm_mips_callbacks->handle_guest_exit(vcpu);
+		break;
+
 	default:
 		if (cause & CAUSEF_BD)
 			opc += 1;
diff --git a/arch/mips/kvm/trace.h b/arch/mips/kvm/trace.h
index 6e43c89114b8..0c59282a2f7d 100644
--- a/arch/mips/kvm/trace.h
+++ b/arch/mips/kvm/trace.h
@@ -62,6 +62,7 @@ DEFINE_EVENT(kvm_transition, kvm_out,
 #define KVM_TRACE_EXIT_MSA_FPE		14
 #define KVM_TRACE_EXIT_FPE		15
 #define KVM_TRACE_EXIT_MSA_DISABLED	21
+#define KVM_TRACE_EXIT_GUEST_EXIT	27
 /* Further exit reasons */
 #define KVM_TRACE_EXIT_WAIT		32
 #define KVM_TRACE_EXIT_CACHE		33
@@ -92,6 +93,7 @@ DEFINE_EVENT(kvm_transition, kvm_out,
 	{ KVM_TRACE_EXIT_MSA_FPE,	"MSA FPE" },		\
 	{ KVM_TRACE_EXIT_FPE,		"FPE" },		\
 	{ KVM_TRACE_EXIT_MSA_DISABLED,	"MSA Disabled" },	\
+	{ KVM_TRACE_EXIT_GUEST_EXIT,	"Guest Exit" },		\
 	{ KVM_TRACE_EXIT_WAIT,		"WAIT" },		\
 	{ KVM_TRACE_EXIT_CACHE,		"CACHE" },		\
 	{ KVM_TRACE_EXIT_SIGNAL,	"Signal" },		\
diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
index c8a0e927220b..1e039fb592e0 100644
--- a/arch/mips/kvm/trap_emul.c
+++ b/arch/mips/kvm/trap_emul.c
@@ -40,6 +40,29 @@ static gpa_t kvm_trap_emul_gva_to_gpa_cb(gva_t gva)
 	return gpa;
 }
 
+static int kvm_trap_emul_no_handler(struct kvm_vcpu *vcpu)
+{
+	u32 __user *opc = (u32 __user *) vcpu->arch.pc;
+	u32 cause = vcpu->arch.host_cp0_cause;
+	u32 exccode = (cause & CAUSEF_EXCCODE) >> CAUSEB_EXCCODE;
+	unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
+	u32 inst = 0;
+
+	/*
+	 *  Fetch the instruction.
+	 */
+	if (cause & CAUSEF_BD)
+		opc += 1;
+	kvm_get_badinstr(opc, vcpu, &inst);
+
+	kvm_err("Exception Code: %d not handled @ PC: %p, inst: 0x%08x BadVaddr: %#lx Status: %#lx\n",
+		exccode, opc, inst, badvaddr,
+		kvm_read_c0_guest_status(vcpu->arch.cop0));
+	kvm_arch_vcpu_dump_regs(vcpu);
+	vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+	return RESUME_HOST;
+}
+
 static int kvm_trap_emul_handle_cop_unusable(struct kvm_vcpu *vcpu)
 {
 	struct mips_coproc *cop0 = vcpu->arch.cop0;
@@ -1251,6 +1274,7 @@ static struct kvm_mips_callbacks kvm_trap_emul_callbacks = {
 	.handle_msa_fpe = kvm_trap_emul_handle_msa_fpe,
 	.handle_fpe = kvm_trap_emul_handle_fpe,
 	.handle_msa_disabled = kvm_trap_emul_handle_msa_disabled,
+	.handle_guest_exit = kvm_trap_emul_no_handler,
 
 	.hardware_enable = kvm_trap_emul_hardware_enable,
 	.hardware_disable = kvm_trap_emul_hardware_disable,
-- 
git-series 0.8.10
