Subject: Re: [PATCH v2 1/1] KVM: PPC: Book3S: correct width in XER handling

From: Alexander Graf <[email-masked]>
Date: Tue, 26 May 2015 10:35:08 +0200

On 26.05.15 02:27, 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 <[email-masked]>
> ---
> 
> v2:
> 
> Also extend kvmppc_book3s_shadow_vcpu.xer to 64 bit.
> 
>  arch/powerpc/include/asm/kvm_book3s.h     |    4 ++--
>  arch/powerpc/include/asm/kvm_book3s_asm.h |    2 +-
>  arch/powerpc/kvm/book3s_hv_rmhandlers.S   |    6 +++---
>  arch/powerpc/kvm/book3s_segment.S         |    4 ++--
>  4 files changed, 8 insertions(+), 8 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)

Now we have book3s and booke files with different prototypes on the same
inline function names. That's really ugly. Please keep them in sync ;).

Alex

>  {
>  	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/include/asm/kvm_book3s_asm.h b/arch/powerpc/include/asm/kvm_book3s_asm.h
> index 5bdfb5d..c4ccd2d 100644
> --- a/arch/powerpc/include/asm/kvm_book3s_asm.h
> +++ b/arch/powerpc/include/asm/kvm_book3s_asm.h
> @@ -112,7 +112,7 @@ struct kvmppc_book3s_shadow_vcpu {
>  	bool in_use;
>  	ulong gpr[14];
>  	u32 cr;
> -	u32 xer;
> +	ulong xer;
>  	ulong ctr;
>  	ulong lr;
>  	ulong pc;
> 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)
>  
>  	mtctr	r8
>  	mtlr	r9
> @@ -237,7 +237,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
>  	mfctr	r8
>  	mflr	r9
>  
> -	stw	r5, SVCPU_XER(r13)
> +	PPC_STL	r5, SVCPU_XER(r13)
>  	PPC_STL	r6, SVCPU_FAULT_DAR(r13)
>  	stw	r7, SVCPU_FAULT_DSISR(r13)
>  	PPC_STL	r8, SVCPU_CTR(r13)
>