[PATCH] powerpc-kvm: fixing page alignment for TCE

[Alexander Graf]

On 04.09.2012, at 09:36, Alexey Kardashevskiy wrote:

> From: Paul Mackerras <paulus at samba.org>
> 
> TODO: ask Paul to make a proper message.

TODO?

Also, Ben or Paul, please ack if you think it's correct.


Alex

> 
> This is the fix for a host kernel compiled with a page size
> other than 4K (TCE page size). In the case of a 64K page size,
> the host used to lose address bits in hpte_rpn().
> The patch fixes it.
> 
> Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
> ---
> arch/powerpc/kvm/book3s_64_mmu_hv.c |    9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> index 80a5775..a41f11b 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> @@ -503,7 +503,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
> 	struct kvm *kvm = vcpu->kvm;
> 	unsigned long *hptep, hpte[3], r;
> 	unsigned long mmu_seq, psize, pte_size;
> -	unsigned long gfn, hva, pfn;
> +	unsigned long gpa, gfn, hva, pfn;
> 	struct kvm_memory_slot *memslot;
> 	unsigned long *rmap;
> 	struct revmap_entry *rev;
> @@ -541,15 +541,14 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
> 
> 	/* Translate the logical address and get the page */
> 	psize = hpte_page_size(hpte[0], r);
> -	gfn = hpte_rpn(r, psize);
> +	gpa = (r & HPTE_R_RPN & ~(psize - 1)) | (ea & (psize - 1));
> +	gfn = gpa >> PAGE_SHIFT;
> 	memslot = gfn_to_memslot(kvm, gfn);
> 
> 	/* No memslot means it's an emulated MMIO region */
> -	if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID)) {
> -		unsigned long gpa = (gfn << PAGE_SHIFT) | (ea & (psize - 1));
> +	if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
> 		return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea,
> 					      dsisr & DSISR_ISSTORE);
> -	}
> 
> 	if (!kvm->arch.using_mmu_notifiers)
> 		return -EFAULT;		/* should never get here */
> -- 
> 1.7.10.4
> 
> --
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