KVM: MIPS: Introduce and use cpu_guest_has_ldpte

Loongson-3 has lddir/ldpte instructions and their related CP0 registers
are the same as HTW. So we introduce a cpu_guest_has_ldpte flag and use
it to indicate whether we need to save/restore HTW related CP0 registers
(PWBase, PWSize, PWField and PWCtl).
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Reviewed-by: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Co-developed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-Id: <1590220602-3547-7-git-send-email-chenhc@lemote.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/mips/include/asm/cpu-features.h

@@ -682,6 +682,9 @@
 #ifndef cpu_guest_has_htw
 #define cpu_guest_has_htw	(cpu_data[0].guest.options & MIPS_CPU_HTW)
 #endif
+#ifndef cpu_guest_has_ldpte
+#define cpu_guest_has_ldpte	(cpu_data[0].guest.options & MIPS_CPU_LDPTE)
+#endif
 #ifndef cpu_guest_has_mvh
 #define cpu_guest_has_mvh	(cpu_data[0].guest.options & MIPS_CPU_MVH)
 #endif

arch/mips/kernel/cpu-probe.c

@@ -2017,8 +2017,10 @@ static inline void decode_cpucfg(struct cpuinfo_mips *c)
 	if (cfg2 & LOONGSON_CFG2_LEXT2)
 		c->ases |= MIPS_ASE_LOONGSON_EXT2;
 
-	if (cfg2 & LOONGSON_CFG2_LSPW)
+	if (cfg2 & LOONGSON_CFG2_LSPW) {
 		c->options |= MIPS_CPU_LDPTE;
+		c->guest.options |= MIPS_CPU_LDPTE;
+	}
 
 	if (cfg3 & LOONGSON_CFG3_LCAMP)
 		c->ases |= MIPS_ASE_LOONGSON_CAM;

arch/mips/kvm/vz.c

@@ -1706,7 +1706,7 @@ static unsigned long kvm_vz_num_regs(struct kvm_vcpu *vcpu)
 		ret += ARRAY_SIZE(kvm_vz_get_one_regs_contextconfig);
 	if (cpu_guest_has_segments)
 		ret += ARRAY_SIZE(kvm_vz_get_one_regs_segments);
-	if (cpu_guest_has_htw)
+	if (cpu_guest_has_htw || cpu_guest_has_ldpte)
 		ret += ARRAY_SIZE(kvm_vz_get_one_regs_htw);
 	if (cpu_guest_has_maar && !cpu_guest_has_dyn_maar)
 		ret += 1 + ARRAY_SIZE(vcpu->arch.maar);
@@ -1755,7 +1755,7 @@ static int kvm_vz_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices)
 			return -EFAULT;
 		indices += ARRAY_SIZE(kvm_vz_get_one_regs_segments);
 	}
-	if (cpu_guest_has_htw) {
+	if (cpu_guest_has_htw || cpu_guest_has_ldpte) {
 		if (copy_to_user(indices, kvm_vz_get_one_regs_htw,
 				 sizeof(kvm_vz_get_one_regs_htw)))
 			return -EFAULT;
@@ -1878,17 +1878,17 @@ static int kvm_vz_get_one_reg(struct kvm_vcpu *vcpu,
 		*v = read_gc0_segctl2();
 		break;
 	case KVM_REG_MIPS_CP0_PWBASE:
-		if (!cpu_guest_has_htw)
+		if (!cpu_guest_has_htw && !cpu_guest_has_ldpte)
 			return -EINVAL;
 		*v = read_gc0_pwbase();
 		break;
 	case KVM_REG_MIPS_CP0_PWFIELD:
-		if (!cpu_guest_has_htw)
+		if (!cpu_guest_has_htw && !cpu_guest_has_ldpte)
 			return -EINVAL;
 		*v = read_gc0_pwfield();
 		break;
 	case KVM_REG_MIPS_CP0_PWSIZE:
-		if (!cpu_guest_has_htw)
+		if (!cpu_guest_has_htw && !cpu_guest_has_ldpte)
 			return -EINVAL;
 		*v = read_gc0_pwsize();
 		break;
@@ -1896,7 +1896,7 @@ static int kvm_vz_get_one_reg(struct kvm_vcpu *vcpu,
 		*v = (long)read_gc0_wired();
 		break;
 	case KVM_REG_MIPS_CP0_PWCTL:
-		if (!cpu_guest_has_htw)
+		if (!cpu_guest_has_htw && !cpu_guest_has_ldpte)
 			return -EINVAL;
 		*v = read_gc0_pwctl();
 		break;
@@ -2101,17 +2101,17 @@ static int kvm_vz_set_one_reg(struct kvm_vcpu *vcpu,
 		write_gc0_segctl2(v);
 		break;
 	case KVM_REG_MIPS_CP0_PWBASE:
-		if (!cpu_guest_has_htw)
+		if (!cpu_guest_has_htw && !cpu_guest_has_ldpte)
 			return -EINVAL;
 		write_gc0_pwbase(v);
 		break;
 	case KVM_REG_MIPS_CP0_PWFIELD:
-		if (!cpu_guest_has_htw)
+		if (!cpu_guest_has_htw && !cpu_guest_has_ldpte)
 			return -EINVAL;
 		write_gc0_pwfield(v);
 		break;
 	case KVM_REG_MIPS_CP0_PWSIZE:
-		if (!cpu_guest_has_htw)
+		if (!cpu_guest_has_htw && !cpu_guest_has_ldpte)
 			return -EINVAL;
 		write_gc0_pwsize(v);
 		break;
@@ -2119,7 +2119,7 @@ static int kvm_vz_set_one_reg(struct kvm_vcpu *vcpu,
 		change_gc0_wired(MIPSR6_WIRED_WIRED, v);
 		break;
 	case KVM_REG_MIPS_CP0_PWCTL:
-		if (!cpu_guest_has_htw)
+		if (!cpu_guest_has_htw && !cpu_guest_has_ldpte)
 			return -EINVAL;
 		write_gc0_pwctl(v);
 		break;
@@ -2580,7 +2580,7 @@ static int kvm_vz_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	}
 
 	/* restore HTW registers */
-	if (cpu_guest_has_htw) {
+	if (cpu_guest_has_htw || cpu_guest_has_ldpte) {
 		kvm_restore_gc0_pwbase(cop0);
 		kvm_restore_gc0_pwfield(cop0);
 		kvm_restore_gc0_pwsize(cop0);
@@ -2685,8 +2685,8 @@ static int kvm_vz_vcpu_put(struct kvm_vcpu *vcpu, int cpu)
 	}
 
 	/* save HTW registers if enabled in guest */
-	if (cpu_guest_has_htw &&
-	    kvm_read_sw_gc0_config3(cop0) & MIPS_CONF3_PW) {
+	if (cpu_guest_has_ldpte || (cpu_guest_has_htw &&
+	    kvm_read_sw_gc0_config3(cop0) & MIPS_CONF3_PW)) {
 		kvm_save_gc0_pwbase(cop0);
 		kvm_save_gc0_pwfield(cop0);
 		kvm_save_gc0_pwsize(cop0);