[PATCH 1/1] KVM: PPC: Book3S: correct width in XER handling

[Sam Bobroff]

On Mon, May 25, 2015 at 11:08:08PM +0200, Alexander Graf wrote:
> 
> 
> On 20.05.15 07:26, Sam Bobroff wrote:
> > In 64 bit kernels, the Fixed Point Exception Register (XER) is a 64
> > bit field (e.g. in kvm_regs and kvm_vcpu_arch) and in most places it is
> > accessed as such.
> > 
> > This patch corrects places where it is accessed as a 32 bit field by a
> > 64 bit kernel.  In some cases this is via a 32 bit load or store
> > instruction which, depending on endianness, will cause either the
> > lower or upper 32 bits to be missed.  In another case it is cast as a
> > u32, causing the upper 32 bits to be cleared.
> > 
> > This patch corrects those places by extending the access methods to
> > 64 bits.
> > 
> > Signed-off-by: Sam Bobroff <sam.bobroff at au1.ibm.com>
> > ---
> > 
> >  arch/powerpc/include/asm/kvm_book3s.h   |    4 ++--
> >  arch/powerpc/kvm/book3s_hv_rmhandlers.S |    6 +++---
> >  arch/powerpc/kvm/book3s_segment.S       |    4 ++--
> >  3 files changed, 7 insertions(+), 7 deletions(-)
> > 
> > diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
> > index b91e74a..05a875a 100644
> > --- a/arch/powerpc/include/asm/kvm_book3s.h
> > +++ b/arch/powerpc/include/asm/kvm_book3s.h
> > @@ -225,12 +225,12 @@ static inline u32 kvmppc_get_cr(struct kvm_vcpu *vcpu)
> >  	return vcpu->arch.cr;
> >  }
> >  
> > -static inline void kvmppc_set_xer(struct kvm_vcpu *vcpu, u32 val)
> > +static inline void kvmppc_set_xer(struct kvm_vcpu *vcpu, ulong val)
> >  {
> >  	vcpu->arch.xer = val;
> >  }
> >  
> > -static inline u32 kvmppc_get_xer(struct kvm_vcpu *vcpu)
> > +static inline ulong kvmppc_get_xer(struct kvm_vcpu *vcpu)
> >  {
> >  	return vcpu->arch.xer;
> >  }
> > diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> > index 4d70df2..d75be59 100644
> > --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> > +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> > @@ -870,7 +870,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
> >  	blt	hdec_soon
> >  
> >  	ld	r6, VCPU_CTR(r4)
> > -	lwz	r7, VCPU_XER(r4)
> > +	ld	r7, VCPU_XER(r4)
> >  
> >  	mtctr	r6
> >  	mtxer	r7
> > @@ -1103,7 +1103,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
> >  	mfctr	r3
> >  	mfxer	r4
> >  	std	r3, VCPU_CTR(r9)
> > -	stw	r4, VCPU_XER(r9)
> > +	std	r4, VCPU_XER(r9)
> >  
> >  	/* If this is a page table miss then see if it's theirs or ours */
> >  	cmpwi	r12, BOOK3S_INTERRUPT_H_DATA_STORAGE
> > @@ -1675,7 +1675,7 @@ kvmppc_hdsi:
> >  	bl	kvmppc_msr_interrupt
> >  fast_interrupt_c_return:
> >  6:	ld	r7, VCPU_CTR(r9)
> > -	lwz	r8, VCPU_XER(r9)
> > +	ld	r8, VCPU_XER(r9)
> >  	mtctr	r7
> >  	mtxer	r8
> >  	mr	r4, r9
> > diff --git a/arch/powerpc/kvm/book3s_segment.S b/arch/powerpc/kvm/book3s_segment.S
> > index acee37c..ca8f174 100644
> > --- a/arch/powerpc/kvm/book3s_segment.S
> > +++ b/arch/powerpc/kvm/book3s_segment.S
> > @@ -123,7 +123,7 @@ no_dcbz32_on:
> >  	PPC_LL	r8, SVCPU_CTR(r3)
> >  	PPC_LL	r9, SVCPU_LR(r3)
> >  	lwz	r10, SVCPU_CR(r3)
> > -	lwz	r11, SVCPU_XER(r3)
> > +	PPC_LL	r11, SVCPU_XER(r3)
> 
> struct kvmppc_book3s_shadow_vcpu {
>         bool in_use;
>         ulong gpr[14];
>         u32 cr;
>         u32 xer;
> [...]
> 
> so at least this change looks wrong. Please double-check all fields in
> your patch again.
> 
> 
> Alex

Thanks for the review and the catch!

The xer field in kvm_vcpu_arch is already ulong, so it looks like the one in
kvmppc_book3s_shadow_vcpu is the only other case. I'll fix that and repost.

Cheers,
Sam.