On Thu, Jan 21, 2016 at 06:39:36PM +1100, Alexey Kardashevskiy wrote: > Upcoming multi-tce support (H_PUT_TCE_INDIRECT/H_STUFF_TCE hypercalls) > will validate TCE (not to have unexpected bits) and IO address > (to be within the DMA window boundaries). > > This introduces helpers to validate TCE and IO address. The helpers are > exported as they compile into vmlinux (to work in realmode) and will be > used later by KVM kernel module in virtual mode. > > Signed-off-by: Alexey Kardashevskiy <[email protected]> > --- > Changes: > v2: > * added note to the commit log about why new helpers are exported > * did not add a note that xxx_validate() validate TCEs for KVM (not for > host kernel DMA) as the helper names and file location tell what are > they for > --- > arch/powerpc/include/asm/kvm_ppc.h | 4 ++ > arch/powerpc/kvm/book3s_64_vio_hv.c | 92 > ++++++++++++++++++++++++++++++++----- > 2 files changed, 84 insertions(+), 12 deletions(-) > > diff --git a/arch/powerpc/include/asm/kvm_ppc.h > b/arch/powerpc/include/asm/kvm_ppc.h > index 2241d53..9513911 100644 > --- a/arch/powerpc/include/asm/kvm_ppc.h > +++ b/arch/powerpc/include/asm/kvm_ppc.h > @@ -166,6 +166,10 @@ extern int kvmppc_pseries_do_hcall(struct kvm_vcpu > *vcpu); > > extern long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, > struct kvm_create_spapr_tce *args); > +extern long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt, > + unsigned long ioba, unsigned long npages); > +extern long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *tt, > + unsigned long tce); > extern long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn, > unsigned long ioba, unsigned long tce); > extern long kvmppc_h_get_tce(struct kvm_vcpu *vcpu, unsigned long liobn, > diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c > b/arch/powerpc/kvm/book3s_64_vio_hv.c > index e142171..8cd3a95 100644 > --- a/arch/powerpc/kvm/book3s_64_vio_hv.c > +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c > @@ -36,6 +36,7 @@ > #include <asm/kvm_host.h> > #include <asm/udbg.h> > #include <asm/iommu.h> > +#include <asm/tce.h> > > #define TCES_PER_PAGE (PAGE_SIZE / sizeof(u64)) > > @@ -64,18 +65,90 @@ static struct kvmppc_spapr_tce_table > *kvmppc_find_table(struct kvm_vcpu *vcpu, > * WARNING: This will be called in real-mode on HV KVM and virtual > * mode on PR KVM > */ > -static long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt, > +long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt, > unsigned long ioba, unsigned long npages) > { > - unsigned long mask = (1ULL << IOMMU_PAGE_SHIFT_4K) - 1; > + unsigned long mask = IOMMU_PAGE_MASK_4K; > unsigned long idx = ioba >> IOMMU_PAGE_SHIFT_4K; > unsigned long size = stt->window_size >> IOMMU_PAGE_SHIFT_4K; > > - if ((ioba & mask) || (idx + npages > size)) > + if ((ioba & ~mask) || (idx + npages > size)) > 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 > + * to the table and user space is supposed to process them), we can skip > + * checking other things (such as TCE is a guest RAM address or the page > + * was actually allocated). > + * > + * WARNING: This will be called in real-mode on HV KVM and virtual > + * mode on PR KVM > + */ > +long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt, > unsigned long tce)
It would be nice to write this in terms of kvmppc_ioba_validate() above.
> +{
> + unsigned long mask = IOMMU_PAGE_MASK_4K | TCE_PCI_WRITE | TCE_PCI_READ;
> +
> + if (tce & ~mask)
> + return H_PARAMETER;
> +
> + return H_SUCCESS;
> +}
> +EXPORT_SYMBOL_GPL(kvmppc_tce_validate);
> +
> +/* Note on the use of page_address() in real mode,
> + *
> + * It is safe to use page_address() in real mode on ppc64 because
> + * page_address() is always defined as lowmem_page_address()
> + * which returns __va(PFN_PHYS(page_to_pfn(page))) which is arithmetial
> + * operation and does not access page struct.
> + *
> + * Theoretically page_address() could be defined different
> + * but either WANT_PAGE_VIRTUAL or HASHED_PAGE_VIRTUAL
> + * should be enabled.
> + * WANT_PAGE_VIRTUAL is never enabled on ppc32/ppc64,
> + * HASHED_PAGE_VIRTUAL could be enabled for ppc32 only and only
> + * if CONFIG_HIGHMEM is defined. As CONFIG_SPARSEMEM_VMEMMAP
> + * is not expected to be enabled on ppc32, page_address()
> + * is safe for ppc32 as well.
> + *
> + * WARNING: This will be called in real-mode on HV KVM and virtual
> + * mode on PR KVM
> + */
> +static u64 *kvmppc_page_address(struct page *page)
> +{
> +#if defined(HASHED_PAGE_VIRTUAL) || defined(WANT_PAGE_VIRTUAL)
> +#error TODO: fix to avoid page_address() here
> +#endif
> + return (u64 *) page_address(page);
> +}
> +
> +/*
> + * Handles TCE requests for emulated devices.
> + * Puts guest TCE values to the table and expects user space to convert them.
> + * Called in both real and virtual modes.
> + * Cannot fail so kvmppc_tce_validate must be called before it.
> + *
> + * WARNING: This will be called in real-mode on HV KVM and virtual
> + * mode on PR KVM
> + */
> +void kvmppc_tce_put(struct kvmppc_spapr_tce_table *stt,
> + unsigned long idx, unsigned long tce)
> +{
> + struct page *page;
> + u64 *tbl;
> +
> + page = stt->pages[idx / TCES_PER_PAGE];
> + tbl = kvmppc_page_address(page);
> +
> + tbl[idx % TCES_PER_PAGE] = tce;
> +}
> +EXPORT_SYMBOL_GPL(kvmppc_tce_put);
>
> /* WARNING: This will be called in real-mode on HV KVM and virtual
> * mode on PR KVM
> @@ -85,9 +158,6 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long
> liobn,
> {
> struct kvmppc_spapr_tce_table *stt = kvmppc_find_table(vcpu, liobn);
> long ret;
> - unsigned long idx;
> - struct page *page;
> - u64 *tbl;
>
> /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
> /* liobn, ioba, tce); */
> @@ -99,13 +169,11 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned
> long liobn,
> if (ret != H_SUCCESS)
> return ret;
>
> - idx = ioba >> IOMMU_PAGE_SHIFT_4K;
> - page = stt->pages[idx / TCES_PER_PAGE];
> - tbl = (u64 *)page_address(page);
> + ret = kvmppc_tce_validate(stt, tce);
> + if (ret != H_SUCCESS)
> + return ret;
>
> - /* FIXME: Need to validate the TCE itself */
> - /* udbg_printf("tce @ %p\n", &tbl[idx % TCES_PER_PAGE]); */
> - tbl[idx % TCES_PER_PAGE] = tce;
> + kvmppc_tce_put(stt, ioba >> IOMMU_PAGE_SHIFT_4K, tce);
>
> 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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