KVM: PPC: Make shared struct aka magic page guest endian

The shared (magic) page is a data structure that contains often used
supervisor privileged SPRs accessible via memory to the user to reduce
the number of exits we have to take to read/write them.

When we actually share this structure with the guest we have to maintain
it in guest endianness, because some of the patch tricks only work with
native endian load/store operations.

Since we only share the structure with either host or guest in little
endian on book3s_64 pr mode, we don't have to worry about booke or book3s hv.

For booke, the shared struct stays big endian. For book3s_64 hv we maintain
the struct in host native endian, since it never gets shared with the guest.

For book3s_64 pr we introduce a variable that tells us which endianness the
shared struct is in and route every access to it through helper inline
functions that evaluate this variable.

Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 10 insertions, 9 deletions

diff --git a/arch/powerpc/kvm/book3s_64_mmu.c b/arch/powerpc/kvm/book3s_64_mmu.c
index b93c2456253d..278729f4df80 100644
--- a/arch/powerpc/kvm/book3s_64_mmu.c
+++ b/arch/powerpc/kvm/book3s_64_mmu.c
@@ -226,7 +226,7 @@ static int kvmppc_mmu_book3s_64_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
 	/* Magic page override */
 	if (unlikely(mp_ea) &&
 	    unlikely((eaddr & ~0xfffULL) == (mp_ea & ~0xfffULL)) &&
-	    !(vcpu->arch.shared->msr & MSR_PR)) {
+	    !(kvmppc_get_msr(vcpu) & MSR_PR)) {
 		gpte->eaddr = eaddr;
 		gpte->vpage = kvmppc_mmu_book3s_64_ea_to_vp(vcpu, eaddr, data);
 		gpte->raddr = vcpu->arch.magic_page_pa | (gpte->raddr & 0xfff);
@@ -269,9 +269,9 @@ do_second:
 		goto no_page_found;
 	}
 
-	if ((vcpu->arch.shared->msr & MSR_PR) && slbe->Kp)
+	if ((kvmppc_get_msr(vcpu) & MSR_PR) && slbe->Kp)
 		key = 4;
-	else if (!(vcpu->arch.shared->msr & MSR_PR) && slbe->Ks)
+	else if (!(kvmppc_get_msr(vcpu) & MSR_PR) && slbe->Ks)
 		key = 4;
 
 	for (i=0; i<16; i+=2) {
@@ -482,7 +482,7 @@ static void kvmppc_mmu_book3s_64_slbia(struct kvm_vcpu *vcpu)
 		vcpu->arch.slb[i].origv = 0;
 	}
 
-	if (vcpu->arch.shared->msr & MSR_IR) {
+	if (kvmppc_get_msr(vcpu) & MSR_IR) {
 		kvmppc_mmu_flush_segments(vcpu);
 		kvmppc_mmu_map_segment(vcpu, kvmppc_get_pc(vcpu));
 	}
@@ -566,7 +566,7 @@ static int segment_contains_magic_page(struct kvm_vcpu *vcpu, ulong esid)
 {
 	ulong mp_ea = vcpu->arch.magic_page_ea;
 
-	return mp_ea && !(vcpu->arch.shared->msr & MSR_PR) &&
+	return mp_ea && !(kvmppc_get_msr(vcpu) & MSR_PR) &&
 		(mp_ea >> SID_SHIFT) == esid;
 }
 #endif
@@ -579,8 +579,9 @@ static int kvmppc_mmu_book3s_64_esid_to_vsid(struct kvm_vcpu *vcpu, ulong esid,
 	u64 gvsid = esid;
 	ulong mp_ea = vcpu->arch.magic_page_ea;
 	int pagesize = MMU_PAGE_64K;
+	u64 msr = kvmppc_get_msr(vcpu);
 
-	if (vcpu->arch.shared->msr & (MSR_DR|MSR_IR)) {
+	if (msr & (MSR_DR|MSR_IR)) {
 		slb = kvmppc_mmu_book3s_64_find_slbe(vcpu, ea);
 		if (slb) {
 			gvsid = slb->vsid;
@@ -593,7 +594,7 @@ static int kvmppc_mmu_book3s_64_esid_to_vsid(struct kvm_vcpu *vcpu, ulong esid,
 		}
 	}
 
-	switch (vcpu->arch.shared->msr & (MSR_DR|MSR_IR)) {
+	switch (msr & (MSR_DR|MSR_IR)) {
 	case 0:
 		gvsid = VSID_REAL | esid;
 		break;
@@ -626,7 +627,7 @@ static int kvmppc_mmu_book3s_64_esid_to_vsid(struct kvm_vcpu *vcpu, ulong esid,
 		gvsid |= VSID_64K;
 #endif
 
-	if (vcpu->arch.shared->msr & MSR_PR)
+	if (kvmppc_get_msr(vcpu) & MSR_PR)
 		gvsid |= VSID_PR;
 
 	*vsid = gvsid;
@@ -636,7 +637,7 @@ no_slb:
 	/* Catch magic page case */
 	if (unlikely(mp_ea) &&
 	    unlikely(esid == (mp_ea >> SID_SHIFT)) &&
-	    !(vcpu->arch.shared->msr & MSR_PR)) {
+	    !(kvmppc_get_msr(vcpu) & MSR_PR)) {
 		*vsid = VSID_REAL | esid;
 		return 0;
 	}