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

[Alexander Graf <agraf@suse.de>]

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@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