KVM: PPC: Add helper functions to call real mode loaders

Linux contains quite some bits of code to load FPU, Altivec and VSX lazily for
a task. It calls those bits in real mode, coming from an interrupt handler.

For KVM we better reuse those, so let's wrap a bit of trampoline magic around
them and then we can call them from normal module code.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

3 files changed, 44 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index c7db69f1e779..e1b441cce416 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -124,6 +124,9 @@ extern void kvmppc_set_bat(struct kvm_vcpu *vcpu, struct kvmppc_bat *bat,
 extern u32 kvmppc_trampoline_lowmem;
 extern u32 kvmppc_trampoline_enter;
 extern void kvmppc_rmcall(ulong srr0, ulong srr1);
+extern void kvmppc_load_up_fpu(void);
+extern void kvmppc_load_up_altivec(void);
+extern void kvmppc_load_up_vsx(void);
 
 static inline struct kvmppc_vcpu_book3s *to_book3s(struct kvm_vcpu *vcpu)
 {
diff --git a/arch/powerpc/kvm/book3s_64_exports.c b/arch/powerpc/kvm/book3s_64_exports.c
index 99b07125c529..1dd5a1ddfd0d 100644
--- a/arch/powerpc/kvm/book3s_64_exports.c
+++ b/arch/powerpc/kvm/book3s_64_exports.c
@@ -23,3 +23,10 @@
 EXPORT_SYMBOL_GPL(kvmppc_trampoline_enter);
 EXPORT_SYMBOL_GPL(kvmppc_trampoline_lowmem);
 EXPORT_SYMBOL_GPL(kvmppc_rmcall);
+EXPORT_SYMBOL_GPL(kvmppc_load_up_fpu);
+#ifdef CONFIG_ALTIVEC
+EXPORT_SYMBOL_GPL(kvmppc_load_up_altivec);
+#endif
+#ifdef CONFIG_VSX
+EXPORT_SYMBOL_GPL(kvmppc_load_up_vsx);
+#endif
diff --git a/arch/powerpc/kvm/book3s_64_rmhandlers.S b/arch/powerpc/kvm/book3s_64_rmhandlers.S
index e7091c9459a8..c83c60ad96c5 100644
--- a/arch/powerpc/kvm/book3s_64_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_64_rmhandlers.S
@@ -158,6 +158,40 @@ _GLOBAL(kvmppc_rmcall)
         mtsrr1  r4
         RFI
 
+/*
+ * Activate current's external feature (FPU/Altivec/VSX)
+ */
+#define define_load_up(what)                            \
+                                                        \
+_GLOBAL(kvmppc_load_up_ ## what);                       \
+        subi    r1, r1, INT_FRAME_SIZE;                 \
+        mflr    r3;                                     \
+        std     r3, _LINK(r1);                          \
+        mfmsr   r4;                                     \
+        std     r31, GPR3(r1);                          \
+        mr      r31, r4;                                \
+        li      r5, MSR_DR;                             \
+        oris    r5, r5, MSR_EE@h;                       \
+        andc    r4, r4, r5;                             \
+        mtmsr   r4;                                     \
+                                                        \
+        bl      .load_up_ ## what;                      \
+                                                        \
+        mtmsr   r31;                                    \
+        ld      r3, _LINK(r1);                          \
+        ld      r31, GPR3(r1);                          \
+        addi    r1, r1, INT_FRAME_SIZE;                 \
+        mtlr    r3;                                     \
+        blr
+
+define_load_up(fpu)
+#ifdef CONFIG_ALTIVEC
+define_load_up(altivec)
+#endif
+#ifdef CONFIG_VSX
+define_load_up(vsx)
+#endif
+
 .global kvmppc_trampoline_lowmem
 kvmppc_trampoline_lowmem:
         .long kvmppc_handler_lowmem_trampoline - _stext