[PULL 06/36] KVM: PPC: Use load_fp/vr_state rather than load_up_fpu/altivec

Alexander Graf
2014-01-29T16:12:45Z

From: Paul Mackerras <paulus@samba.org>

The load_up_fpu and load_up_altivec functions were never intended to
be called from C, and do things like modifying the MSR value in their
callers' stack frames, which are assumed to be interrupt frames. In
addition, on 32-bit Book S they require the MMU to be off.

This makes KVM use the new load_fp_state() and load_vr_state() functions
instead of load_up_fpu/altivec. This means we can remove the assembler
glue in book3s_rmhandlers.S, and potentially fixes a bug on Book E,
where load_up_fpu was called directly from C.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
arch/powerpc/include/asm/kvm_book3s.h | 3 ---
arch/powerpc/include/asm/switch_to.h | 2 --
arch/powerpc/kvm/book3s_exports.c | 4 ---
arch/powerpc/kvm/book3s_pr.c | 18 +++++++++-----
arch/powerpc/kvm/book3s_rmhandlers.S | 47 -----------------------------------
arch/powerpc/kvm/booke.h | 3 ++-
6 files changed, 14 insertions(+), 63 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index 4a594b7..8bb8706 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -186,9 +186,6 @@ extern void kvmppc_update_lpcr(struct kvm *kvm, unsigned long lpcr,

extern void kvmppc_entry_trampoline(void);
extern void kvmppc_hv_entry_trampoline(void);
-extern void kvmppc_load_up_fpu(void);
-extern void kvmppc_load_up_altivec(void);
-extern void kvmppc_load_up_vsx(void);
extern u32 kvmppc_alignment_dsisr(struct kvm_vcpu *vcpu, unsigned int inst);
extern ulong kvmppc_alignment_dar(struct kvm_vcpu *vcpu, unsigned int inst);
extern int kvmppc_h_pr(struct kvm_vcpu *vcpu, unsigned long cmd);
diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h
index 9ee1261..971ca33 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -25,10 +25,8 @@ static inline void save_tar(struct thread_struct *prev)
static inline void save_tar(struct thread_struct *prev) {}
#endif

-extern void load_up_fpu(void);
extern void enable_kernel_fp(void);
extern void enable_kernel_altivec(void);
-extern void load_up_altivec(struct task_struct *);
extern int emulate_altivec(struct pt_regs *);
extern void __giveup_vsx(struct task_struct *);
extern void giveup_vsx(struct task_struct *);
diff --git a/arch/powerpc/kvm/book3s_exports.c b/arch/powerpc/kvm/book3s_exports.c
index 852989a..20d4ea8 100644
--- a/arch/powerpc/kvm/book3s_exports.c
+++ b/arch/powerpc/kvm/book3s_exports.c
@@ -25,9 +25,5 @@ EXPORT_SYMBOL_GPL(kvmppc_hv_entry_trampoline);
#endif
#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
EXPORT_SYMBOL_GPL(kvmppc_entry_trampoline);
-EXPORT_SYMBOL_GPL(kvmppc_load_up_fpu);
-#ifdef CONFIG_ALTIVEC
-EXPORT_SYMBOL_GPL(kvmppc_load_up_altivec);
-#endif
#endif

diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 21bf7c5..d63a91f 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -691,7 +691,8 @@ static int kvmppc_handle_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr,
#endif
t->fp_state.fpscr = vcpu->arch.fpscr;
t->fpexc_mode = 0;
- kvmppc_load_up_fpu();
+ enable_kernel_fp();
+ load_fp_state(&t->fp_state);
}

if (msr & MSR_VEC) {
@@ -699,7 +700,8 @@ static int kvmppc_handle_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr,
memcpy(t->vr_state.vr, vcpu->arch.vr, sizeof(vcpu->arch.vr));
t->vr_state.vscr = vcpu->arch.vscr;
t->vrsave = -1;
- kvmppc_load_up_altivec();
+ enable_kernel_altivec();
+ load_vr_state(&t->vr_state);
#endif
}

@@ -722,11 +724,15 @@ static void kvmppc_handle_lost_ext(struct kvm_vcpu *vcpu)
if (!lost_ext)
return;

- if (lost_ext & MSR_FP)
- kvmppc_load_up_fpu();
+ if (lost_ext & MSR_FP) {
+ enable_kernel_fp();
+ load_fp_state(&current->thread.fp_state);
+ }
#ifdef CONFIG_ALTIVEC
- if (lost_ext & MSR_VEC)
- kvmppc_load_up_altivec();
+ if (lost_ext & MSR_VEC) {
+ enable_kernel_altivec();
+ load_vr_state(&current->thread.vr_state);
+ }
#endif
current->thread.regs->msr |= lost_ext;
}
diff --git a/arch/powerpc/kvm/book3s_rmhandlers.S b/arch/powerpc/kvm/book3s_rmhandlers.S
index a38c4c9..c78ffbc 100644
--- a/arch/powerpc/kvm/book3s_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_rmhandlers.S
@@ -166,51 +166,4 @@ _GLOBAL(kvmppc_entry_trampoline)
mtsrr1 r6
RFI

-#if defined(CONFIG_PPC_BOOK3S_32)
-#define STACK_LR INT_FRAME_SIZE+4
-
-/* load_up_xxx have to run with MSR_DR=0 on Book3S_32 */
-#define MSR_EXT_START \
- PPC_STL r20, _NIP(r1); \
- mfmsr r20; \
- LOAD_REG_IMMEDIATE(r3, MSR_DR|MSR_EE); \
- andc r3,r20,r3; /* Disable DR,EE */ \
- mtmsr r3; \
- sync
-
-#define MSR_EXT_END \
- mtmsr r20; /* Enable DR,EE */ \
- sync; \
- PPC_LL r20, _NIP(r1)
-
-#elif defined(CONFIG_PPC_BOOK3S_64)
-#define STACK_LR _LINK
-#define MSR_EXT_START
-#define MSR_EXT_END
-#endif
-
-/*
- * Activate current's external feature (FPU/Altivec/VSX)
- */
-#define define_load_up(what) \
- \
-_GLOBAL(kvmppc_load_up_ ## what); \
- PPC_STLU r1, -INT_FRAME_SIZE(r1); \
- mflr r3; \
- PPC_STL r3, STACK_LR(r1); \
- MSR_EXT_START; \
- \
- bl FUNC(load_up_ ## what); \
- \
- MSR_EXT_END; \
- PPC_LL r3, STACK_LR(r1); \
- mtlr r3; \
- addi r1, r1, INT_FRAME_SIZE; \
- blr
-
-define_load_up(fpu)
-#ifdef CONFIG_ALTIVEC
-define_load_up(altivec)
-#endif
-
#include "book3s_segment.S"
diff --git a/arch/powerpc/kvm/booke.h b/arch/powerpc/kvm/booke.h
index 09bfd9b..fe59f22 100644
--- a/arch/powerpc/kvm/booke.h
+++ b/arch/powerpc/kvm/booke.h
@@ -136,7 +136,8 @@ static inline void kvmppc_load_guest_fp(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_PPC_FPU
if (vcpu->fpu_active && !(current->thread.regs->msr & MSR_FP)) {
- load_up_fpu();
+ enable_kernel_fp();
+ load_fp_state(&current->thread.fp_state);
current->thread.regs->msr |= MSR_FP;
}
#endif
--
1.8.1.4