Merge tag 'kvm_mips_4.12_1' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/kvm-mips

From: James Hogan <james.hogan@imgtec.com>

KVM: MIPS: VZ support, Octeon III, and TLBR

Add basic support for the MIPS Virtualization Module (generally known as
MIPS VZ) in KVM. We primarily support the ImgTec P5600, P6600, I6400,
and Cavium Octeon III cores so far. Support is included for the
following VZ / guest hardware features:
- MIPS32 and MIPS64, r5 (VZ requires r5 or later) and r6
- TLBs with GuestID (IMG cores) or Root ASID Dealias (Octeon III)
- Shared physical root/guest TLB (IMG cores)
- FPU / MSA
- Cop0 timer (up to 1GHz for now due to soft timer limit)
- Segmentation control (EVA)
- Hardware page table walker (HTW) both for root and guest TLB

Also included is a proper implementation of the TLBR instruction for the
trap & emulate MIPS KVM implementation.

Preliminary MIPS architecture changes are applied directly with Ralf's
ack.

1 files changed, 89 insertions, 31 deletions

diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 15a1b1716c2e..1fc6fef463db 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -59,6 +59,16 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ "fpe",	  VCPU_STAT(fpe_exits),		 KVM_STAT_VCPU },
 	{ "msa_disabled", VCPU_STAT(msa_disabled_exits), KVM_STAT_VCPU },
 	{ "flush_dcache", VCPU_STAT(flush_dcache_exits), KVM_STAT_VCPU },
+#ifdef CONFIG_KVM_MIPS_VZ
+	{ "vz_gpsi",	  VCPU_STAT(vz_gpsi_exits),	 KVM_STAT_VCPU },
+	{ "vz_gsfc",	  VCPU_STAT(vz_gsfc_exits),	 KVM_STAT_VCPU },
+	{ "vz_hc",	  VCPU_STAT(vz_hc_exits),	 KVM_STAT_VCPU },
+	{ "vz_grr",	  VCPU_STAT(vz_grr_exits),	 KVM_STAT_VCPU },
+	{ "vz_gva",	  VCPU_STAT(vz_gva_exits),	 KVM_STAT_VCPU },
+	{ "vz_ghfc",	  VCPU_STAT(vz_ghfc_exits),	 KVM_STAT_VCPU },
+	{ "vz_gpa",	  VCPU_STAT(vz_gpa_exits),	 KVM_STAT_VCPU },
+	{ "vz_resvd",	  VCPU_STAT(vz_resvd_exits),	 KVM_STAT_VCPU },
+#endif
 	{ "halt_successful_poll", VCPU_STAT(halt_successful_poll), KVM_STAT_VCPU },
 	{ "halt_attempted_poll", VCPU_STAT(halt_attempted_poll), KVM_STAT_VCPU },
 	{ "halt_poll_invalid", VCPU_STAT(halt_poll_invalid), KVM_STAT_VCPU },
@@ -66,6 +76,19 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{NULL}
 };
 
+bool kvm_trace_guest_mode_change;
+
+int kvm_guest_mode_change_trace_reg(void)
+{
+	kvm_trace_guest_mode_change = 1;
+	return 0;
+}
+
+void kvm_guest_mode_change_trace_unreg(void)
+{
+	kvm_trace_guest_mode_change = 0;
+}
+
 /*
  * XXXKYMA: We are simulatoring a processor that has the WII bit set in
  * Config7, so we are "runnable" if interrupts are pending
@@ -82,7 +105,12 @@ int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
 
 int kvm_arch_hardware_enable(void)
 {
-	return 0;
+	return kvm_mips_callbacks->hardware_enable();
+}
+
+void kvm_arch_hardware_disable(void)
+{
+	kvm_mips_callbacks->hardware_disable();
 }
 
 int kvm_arch_hardware_setup(void)
@@ -97,6 +125,18 @@ void kvm_arch_check_processor_compat(void *rtn)
 
 int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 {
+	switch (type) {
+#ifdef CONFIG_KVM_MIPS_VZ
+	case KVM_VM_MIPS_VZ:
+#else
+	case KVM_VM_MIPS_TE:
+#endif
+		break;
+	default:
+		/* Unsupported KVM type */
+		return -EINVAL;
+	};
+
 	/* Allocate page table to map GPA -> RPA */
 	kvm->arch.gpa_mm.pgd = kvm_pgd_alloc();
 	if (!kvm->arch.gpa_mm.pgd)
@@ -301,8 +341,10 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 	/* Build guest exception vectors dynamically in unmapped memory */
 	handler = gebase + 0x2000;
 
-	/* TLB refill */
+	/* TLB refill (or XTLB refill on 64-bit VZ where KX=1) */
 	refill_start = gebase;
+	if (IS_ENABLED(CONFIG_KVM_MIPS_VZ) && IS_ENABLED(CONFIG_64BIT))
+		refill_start += 0x080;
 	refill_end = kvm_mips_build_tlb_refill_exception(refill_start, handler);
 
 	/* General Exception Entry point */
@@ -353,9 +395,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 
 	/* Init */
 	vcpu->arch.last_sched_cpu = -1;
-
-	/* Start off the timer */
-	kvm_mips_init_count(vcpu);
+	vcpu->arch.last_exec_cpu = -1;
 
 	return vcpu;
 
@@ -1059,7 +1099,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		r = cpu_has_msa && !(boot_cpu_data.msa_id & MSA_IR_WRPF);
 		break;
 	default:
-		r = 0;
+		r = kvm_mips_callbacks->check_extension(kvm, ext);
 		break;
 	}
 	return r;
@@ -1067,7 +1107,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 
 int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
 {
-	return kvm_mips_pending_timer(vcpu);
+	return kvm_mips_pending_timer(vcpu) ||
+		kvm_read_c0_guest_cause(vcpu->arch.cop0) & C_TI;
 }
 
 int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu)
@@ -1092,7 +1133,7 @@ int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu)
 	kvm_debug("\tlo: 0x%08lx\n", vcpu->arch.lo);
 
 	cop0 = vcpu->arch.cop0;
-	kvm_debug("\tStatus: 0x%08lx, Cause: 0x%08lx\n",
+	kvm_debug("\tStatus: 0x%08x, Cause: 0x%08x\n",
 		  kvm_read_c0_guest_status(cop0),
 		  kvm_read_c0_guest_cause(cop0));
 
@@ -1208,7 +1249,8 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
 	vcpu->mode = OUTSIDE_GUEST_MODE;
 
 	/* re-enable HTW before enabling interrupts */
-	htw_start();
+	if (!IS_ENABLED(CONFIG_KVM_MIPS_VZ))
+		htw_start();
 
 	/* Set a default exit reason */
 	run->exit_reason = KVM_EXIT_UNKNOWN;
@@ -1226,17 +1268,20 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
 			cause, opc, run, vcpu);
 	trace_kvm_exit(vcpu, exccode);
 
-	/*
-	 * Do a privilege check, if in UM most of these exit conditions end up
-	 * causing an exception to be delivered to the Guest Kernel
-	 */
-	er = kvm_mips_check_privilege(cause, opc, run, vcpu);
-	if (er == EMULATE_PRIV_FAIL) {
-		goto skip_emul;
-	} else if (er == EMULATE_FAIL) {
-		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
-		ret = RESUME_HOST;
-		goto skip_emul;
+	if (!IS_ENABLED(CONFIG_KVM_MIPS_VZ)) {
+		/*
+		 * Do a privilege check, if in UM most of these exit conditions
+		 * end up causing an exception to be delivered to the Guest
+		 * Kernel
+		 */
+		er = kvm_mips_check_privilege(cause, opc, run, vcpu);
+		if (er == EMULATE_PRIV_FAIL) {
+			goto skip_emul;
+		} else if (er == EMULATE_FAIL) {
+			run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+			ret = RESUME_HOST;
+			goto skip_emul;
+		}
 	}
 
 	switch (exccode) {
@@ -1267,7 +1312,7 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
 		break;
 
 	case EXCCODE_TLBS:
-		kvm_debug("TLB ST fault:  cause %#x, status %#lx, PC: %p, BadVaddr: %#lx\n",
+		kvm_debug("TLB ST fault:  cause %#x, status %#x, PC: %p, BadVaddr: %#lx\n",
 			  cause, kvm_read_c0_guest_status(vcpu->arch.cop0), opc,
 			  badvaddr);
 
@@ -1328,12 +1373,17 @@ 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;
 		inst = 0;
 		kvm_get_badinstr(opc, vcpu, &inst);
-		kvm_err("Exception Code: %d, not yet handled, @ PC: %p, inst: 0x%08x  BadVaddr: %#lx Status: %#lx\n",
+		kvm_err("Exception Code: %d, not yet handled, @ PC: %p, inst: 0x%08x  BadVaddr: %#lx Status: %#x\n",
 			exccode, opc, inst, badvaddr,
 			kvm_read_c0_guest_status(vcpu->arch.cop0));
 		kvm_arch_vcpu_dump_regs(vcpu);
@@ -1346,6 +1396,9 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
 skip_emul:
 	local_irq_disable();
 
+	if (ret == RESUME_GUEST)
+		kvm_vz_acquire_htimer(vcpu);
+
 	if (er == EMULATE_DONE && !(ret & RESUME_HOST))
 		kvm_mips_deliver_interrupts(vcpu, cause);
 
@@ -1391,7 +1444,8 @@ skip_emul:
 	}
 
 	/* Disable HTW before returning to guest or host */
-	htw_stop();
+	if (!IS_ENABLED(CONFIG_KVM_MIPS_VZ))
+		htw_stop();
 
 	return ret;
 }
@@ -1527,16 +1581,18 @@ void kvm_drop_fpu(struct kvm_vcpu *vcpu)
 void kvm_lose_fpu(struct kvm_vcpu *vcpu)
 {
 	/*
-	 * FPU & MSA get disabled in root context (hardware) when it is disabled
-	 * in guest context (software), but the register state in the hardware
-	 * may still be in use. This is why we explicitly re-enable the hardware
-	 * before saving.
+	 * With T&E, FPU & MSA get disabled in root context (hardware) when it
+	 * is disabled in guest context (software), but the register state in
+	 * the hardware may still be in use.
+	 * This is why we explicitly re-enable the hardware before saving.
 	 */
 
 	preempt_disable();
 	if (cpu_has_msa && vcpu->arch.aux_inuse & KVM_MIPS_AUX_MSA) {
-		set_c0_config5(MIPS_CONF5_MSAEN);
-		enable_fpu_hazard();
+		if (!IS_ENABLED(CONFIG_KVM_MIPS_VZ)) {
+			set_c0_config5(MIPS_CONF5_MSAEN);
+			enable_fpu_hazard();
+		}
 
 		__kvm_save_msa(&vcpu->arch);
 		trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_FPU_MSA);
@@ -1549,8 +1605,10 @@ void kvm_lose_fpu(struct kvm_vcpu *vcpu)
 		}
 		vcpu->arch.aux_inuse &= ~(KVM_MIPS_AUX_FPU | KVM_MIPS_AUX_MSA);
 	} else if (vcpu->arch.aux_inuse & KVM_MIPS_AUX_FPU) {
-		set_c0_status(ST0_CU1);
-		enable_fpu_hazard();
+		if (!IS_ENABLED(CONFIG_KVM_MIPS_VZ)) {
+			set_c0_status(ST0_CU1);
+			enable_fpu_hazard();
+		}
 
 		__kvm_save_fpu(&vcpu->arch);
 		vcpu->arch.aux_inuse &= ~KVM_MIPS_AUX_FPU;