[PATCH kernel v5 09/10] KVM: PPC: iommu: Unify TCE checking
David Gibson
david at gibson.dropbear.id.au
Thu Feb 23 15:40:27 AEDT 2017
On Wed, Feb 22, 2017 at 07:21:32PM +1100, Alexey Kardashevskiy wrote:
> Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
I like this, except for one detail
> ---
> arch/powerpc/include/asm/iommu.h | 20 +++++++++++++++-----
> arch/powerpc/include/asm/kvm_ppc.h | 6 ++++--
> arch/powerpc/kernel/iommu.c | 37 +++++++++++++------------------------
> arch/powerpc/kvm/book3s_64_vio_hv.c | 31 +++++++------------------------
> 4 files changed, 39 insertions(+), 55 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
> index 82e77ebf85f4..d4396d1d89df 100644
> --- a/arch/powerpc/include/asm/iommu.h
> +++ b/arch/powerpc/include/asm/iommu.h
> @@ -296,11 +296,21 @@ static inline void iommu_restore(void)
> #endif
>
> /* The API to support IOMMU operations for VFIO */
> -extern int iommu_tce_clear_param_check(struct iommu_table *tbl,
> - unsigned long ioba, unsigned long tce_value,
> - unsigned long npages);
> -extern int iommu_tce_put_param_check(struct iommu_table *tbl,
> - unsigned long ioba, unsigned long tce);
> +extern int iommu_tce_check_ioba(unsigned long page_shift,
> + unsigned long offset, unsigned long size,
> + unsigned long ioba, unsigned long npages);
> +extern int iommu_tce_check_tce(unsigned long page_shift,
> + unsigned long tce);
> +
> +#define iommu_tce_clear_param_check(tbl, ioba, tce_value, npages) \
> + (iommu_tce_check_ioba((tbl)->it_page_shift, \
> + (tbl)->it_offset, (tbl)->it_size, \
> + (ioba), (npages)) || (tce_value))
> +#define iommu_tce_put_param_check(tbl, ioba, tce) \
> + (iommu_tce_check_ioba((tbl)->it_page_shift, \
> + (tbl)->it_offset, (tbl)->it_size, \
> + (ioba), 1) || \
> + iommu_tce_check_tce((tbl)->it_page_shift, (tce)))
>
> extern void iommu_flush_tce(struct iommu_table *tbl);
> extern int iommu_take_ownership(struct iommu_table *tbl);
> diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
> index 37bc9e7e90ba..e04b7fb8ccaa 100644
> --- a/arch/powerpc/include/asm/kvm_ppc.h
> +++ b/arch/powerpc/include/asm/kvm_ppc.h
> @@ -168,8 +168,10 @@ extern long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
> struct kvm_create_spapr_tce_64 *args);
> extern struct kvmppc_spapr_tce_table *kvmppc_find_table(
> struct kvm *kvm, unsigned long liobn);
> -extern long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt,
> - unsigned long ioba, unsigned long npages);
> +#define kvmppc_ioba_validate(stt, ioba, npages) \
> + (iommu_tce_check_ioba((stt)->page_shift, (stt)->offset, \
> + (stt)->size, (ioba), (npages)) ? \
> + H_PARAMETER : H_SUCCESS)
> extern long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *tt,
> unsigned long tce);
> extern long kvmppc_gpa_to_ua(struct kvm *kvm, unsigned long gpa,
> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
> index d02b8d22fb50..a419bd3997ba 100644
> --- a/arch/powerpc/kernel/iommu.c
> +++ b/arch/powerpc/kernel/iommu.c
> @@ -960,47 +960,36 @@ void iommu_flush_tce(struct iommu_table *tbl)
> }
> EXPORT_SYMBOL_GPL(iommu_flush_tce);
>
> -int iommu_tce_clear_param_check(struct iommu_table *tbl,
> - unsigned long ioba, unsigned long tce_value,
> - unsigned long npages)
> +int iommu_tce_check_ioba(unsigned long page_shift,
> + unsigned long offset, unsigned long size,
> + unsigned long ioba, unsigned long npages)
> {
> - /* tbl->it_ops->clear() does not support any value but 0 */
> - if (tce_value)
> - return -EINVAL;
> + unsigned long mask = (1 << page_shift) - 1;
>
> - if (ioba & ~IOMMU_PAGE_MASK(tbl))
> + if (ioba & mask)
> return -EINVAL;
>
> - ioba >>= tbl->it_page_shift;
> - if (ioba < tbl->it_offset)
> + ioba >>= page_shift;
> + if (ioba < offset)
> return -EINVAL;
>
> - if ((ioba + npages) > (tbl->it_offset + tbl->it_size))
> + if ((ioba + 1) > (offset + size))
> return -EINVAL;
>
> return 0;
> }
> -EXPORT_SYMBOL_GPL(iommu_tce_clear_param_check);
> +EXPORT_SYMBOL_GPL(iommu_tce_check_ioba);
>
> -int iommu_tce_put_param_check(struct iommu_table *tbl,
> - unsigned long ioba, unsigned long tce)
> +int iommu_tce_check_tce(unsigned long page_shift, unsigned long tce)
> {
> - if (tce & ~IOMMU_PAGE_MASK(tbl))
> - return -EINVAL;
> -
> - if (ioba & ~IOMMU_PAGE_MASK(tbl))
> - return -EINVAL;
> -
> - ioba >>= tbl->it_page_shift;
> - if (ioba < tbl->it_offset)
> - return -EINVAL;
> + unsigned long mask = (1 << page_shift) - 1;
>
> - if ((ioba + 1) > (tbl->it_offset + tbl->it_size))
> + if (tce & mask)
> return -EINVAL;
This doesn't seem to be quite correctly named, since it doesn't check
a TCE (including permission bits), but rather a GPA.
> return 0;
> }
> -EXPORT_SYMBOL_GPL(iommu_tce_put_param_check);
> +EXPORT_SYMBOL_GPL(iommu_tce_check_tce);
>
> long iommu_tce_xchg(struct iommu_table *tbl, unsigned long entry,
> unsigned long *hpa, enum dma_data_direction *direction)
> diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
> index 0f145fc7a3a5..92d769f4eaea 100644
> --- a/arch/powerpc/kvm/book3s_64_vio_hv.c
> +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
> @@ -62,27 +62,6 @@ struct kvmppc_spapr_tce_table *kvmppc_find_table(struct kvm *kvm,
> EXPORT_SYMBOL_GPL(kvmppc_find_table);
>
> /*
> - * Validates IO address.
> - *
> - * WARNING: This will be called in real-mode on HV KVM and virtual
> - * mode on PR KVM
> - */
> -long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt,
> - unsigned long ioba, unsigned long npages)
> -{
> - unsigned long mask = (1ULL << stt->page_shift) - 1;
> - unsigned long idx = ioba >> stt->page_shift;
> -
> - if ((ioba & mask) || (idx < stt->offset) ||
> - (idx - stt->offset + npages > stt->size) ||
> - (idx + npages < idx))
> - return H_PARAMETER;
> -
> - return H_SUCCESS;
> -}
> -EXPORT_SYMBOL_GPL(kvmppc_ioba_validate);
> -
> -/*
> * Validates TCE address.
> * At the moment flags and page mask are validated.
> * As the host kernel does not access those addresses (just puts them
> @@ -95,10 +74,14 @@ EXPORT_SYMBOL_GPL(kvmppc_ioba_validate);
> */
> long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt, unsigned long tce)
> {
> - unsigned long page_mask = ~((1ULL << stt->page_shift) - 1);
> - unsigned long mask = ~(page_mask | TCE_PCI_WRITE | TCE_PCI_READ);
> + unsigned long gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> + enum dma_data_direction dir = iommu_tce_direction(tce);
>
> - if (tce & mask)
> + /* Allow userspace to poison TCE table */
> + if (dir == DMA_NONE)
> + return H_SUCCESS;
> +
> + if (iommu_tce_check_tce(stt->page_shift, gpa))
> return H_PARAMETER;
>
> return H_SUCCESS;
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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