KVM: PPC: Book3S HV: Basic little-endian guest support

We create a guest MSR from scratch when delivering exceptions in
a few places.  Instead of extracting LPCR[ILE] and inserting it
into MSR_LE each time, we simply create a new variable intr_msr which
contains the entire MSR to use.  For a little-endian guest, userspace
needs to set the ILE (interrupt little-endian) bit in the LPCR for
each vcpu (or at least one vcpu in each virtual core).

[paulus@samba.org - removed H_SET_MODE implementation from original
version of the patch, and made kvmppc_set_lpcr update vcpu->arch.intr_msr.]
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/include/asm/kvm_host.h

@@ -636,6 +636,7 @@ struct kvm_vcpu_arch {
 	spinlock_t tbacct_lock;
 	u64 busy_stolen;
 	u64 busy_preempt;
+	unsigned long intr_msr;
 #endif
 };
 

arch/powerpc/kernel/asm-offsets.c

@@ -480,6 +480,7 @@ int main(void)
 	DEFINE(VCPU_DAR, offsetof(struct kvm_vcpu, arch.shregs.dar));
 	DEFINE(VCPU_VPA, offsetof(struct kvm_vcpu, arch.vpa.pinned_addr));
 	DEFINE(VCPU_VPA_DIRTY, offsetof(struct kvm_vcpu, arch.vpa.dirty));
+	DEFINE(VCPU_INTR_MSR, offsetof(struct kvm_vcpu, arch.intr_msr));
 #endif
 #ifdef CONFIG_PPC_BOOK3S
 	DEFINE(VCPU_VCPUID, offsetof(struct kvm_vcpu, vcpu_id));

arch/powerpc/kvm/book3s_64_mmu_hv.c

@@ -262,7 +262,7 @@ int kvmppc_mmu_hv_init(void)
 
 static void kvmppc_mmu_book3s_64_hv_reset_msr(struct kvm_vcpu *vcpu)
 {
-	kvmppc_set_msr(vcpu, MSR_SF | MSR_ME);
+	kvmppc_set_msr(vcpu, vcpu->arch.intr_msr);
 }
 
 /*

arch/powerpc/kvm/book3s_hv.c

@@ -787,6 +787,27 @@ static void kvmppc_set_lpcr(struct kvm_vcpu *vcpu, u64 new_lpcr)
 	u64 mask;
 
 	spin_lock(&vc->lock);
+	/*
+	 * If ILE (interrupt little-endian) has changed, update the
+	 * MSR_LE bit in the intr_msr for each vcpu in this vcore.
+	 */
+	if ((new_lpcr & LPCR_ILE) != (vc->lpcr & LPCR_ILE)) {
+		struct kvm *kvm = vcpu->kvm;
+		struct kvm_vcpu *vcpu;
+		int i;
+
+		mutex_lock(&kvm->lock);
+		kvm_for_each_vcpu(i, vcpu, kvm) {
+			if (vcpu->arch.vcore != vc)
+				continue;
+			if (new_lpcr & LPCR_ILE)
+				vcpu->arch.intr_msr |= MSR_LE;
+			else
+				vcpu->arch.intr_msr &= ~MSR_LE;
+		}
+		mutex_unlock(&kvm->lock);
+	}
+
 	/*
 	 * Userspace can only modify DPFD (default prefetch depth),
 	 * ILE (interrupt little-endian) and TC (translation control).
@@ -1155,6 +1176,7 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_hv(struct kvm *kvm,
 	spin_lock_init(&vcpu->arch.vpa_update_lock);
 	spin_lock_init(&vcpu->arch.tbacct_lock);
 	vcpu->arch.busy_preempt = TB_NIL;
+	vcpu->arch.intr_msr = MSR_SF | MSR_ME;
 
 	kvmppc_mmu_book3s_hv_init(vcpu);
 

arch/powerpc/kvm/book3s_hv_rmhandlers.S

@@ -812,8 +812,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
 12:	mtspr	SPRN_SRR0, r10
 	mr	r10,r0
 	mtspr	SPRN_SRR1, r11
-	li	r11,(MSR_ME << 1) | 1	/* synthesize MSR_SF | MSR_ME */
-	rotldi	r11,r11,63
+	ld	r11, VCPU_INTR_MSR(r4)
 5:
 
 /*
@@ -1551,8 +1550,7 @@ kvmppc_hdsi:
 	mtspr	SPRN_SRR0, r10
 	mtspr	SPRN_SRR1, r11
 	li	r10, BOOK3S_INTERRUPT_DATA_STORAGE
-	li	r11, (MSR_ME << 1) | 1	/* synthesize MSR_SF | MSR_ME */
-	rotldi	r11, r11, 63
+	ld	r11, VCPU_INTR_MSR(r9)
 fast_interrupt_c_return:
 6:	ld	r7, VCPU_CTR(r9)
 	lwz	r8, VCPU_XER(r9)
@@ -1621,8 +1619,7 @@ kvmppc_hisi:
 1:	mtspr	SPRN_SRR0, r10
 	mtspr	SPRN_SRR1, r11
 	li	r10, BOOK3S_INTERRUPT_INST_STORAGE
-	li	r11, (MSR_ME << 1) | 1	/* synthesize MSR_SF | MSR_ME */
-	rotldi	r11, r11, 63
+	ld	r11, VCPU_INTR_MSR(r9)
 	b	fast_interrupt_c_return
 
 3:	ld	r6, VCPU_KVM(r9)	/* not relocated, use VRMA */
@@ -1665,8 +1662,7 @@ sc_1_fast_return:
 	mtspr	SPRN_SRR0,r10
 	mtspr	SPRN_SRR1,r11
 	li	r10, BOOK3S_INTERRUPT_SYSCALL
-	li	r11, (MSR_ME << 1) | 1  /* synthesize MSR_SF | MSR_ME */
-	rotldi	r11, r11, 63
+	ld	r11, VCPU_INTR_MSR(r9)
 	mr	r4,r9
 	b	fast_guest_return
 
@@ -1994,8 +1990,7 @@ machine_check_realmode:
 	beq	mc_cont
 	/* If not, deliver a machine check.  SRR0/1 are already set */
 	li	r10, BOOK3S_INTERRUPT_MACHINE_CHECK
-	li	r11, (MSR_ME << 1) | 1	/* synthesize MSR_SF | MSR_ME */
-	rotldi	r11, r11, 63
+	ld	r11, VCPU_INTR_MSR(r9)
 	b	fast_interrupt_c_return
 
 /*