From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 575F81A0C62 for ; Mon, 25 Jan 2016 11:43:11 +1100 (AEDT) Date: Mon, 25 Jan 2016 11:12:36 +1100 From: David Gibson To: Alexey Kardashevskiy Cc: linuxppc-dev@lists.ozlabs.org, Paul Mackerras , kvm-ppc@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH kernel v2 5/6] KVM: PPC: Move reusable bits of H_PUT_TCE handler to helpers Message-ID: <20160125001236.GD27454@voom.redhat.com> References: <1453361977-19589-1-git-send-email-aik@ozlabs.ru> <1453361977-19589-6-git-send-email-aik@ozlabs.ru> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="6a4z/rxILaXg6B+u" In-Reply-To: <1453361977-19589-6-git-send-email-aik@ozlabs.ru> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --6a4z/rxILaXg6B+u Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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). >=20 > 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. >=20 > Signed-off-by: Alexey Kardashevskiy > --- > 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(-) >=20 > diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/as= m/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); > =20 > 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/book3= s_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 > #include > #include > +#include > =20 > #define TCES_PER_PAGE (PAGE_SIZE / sizeof(u64)) > =20 > @@ -64,18 +65,90 @@ static struct kvmppc_spapr_tce_table *kvmppc_find_tab= le(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 =3D (1ULL << IOMMU_PAGE_SHIFT_4K) - 1; > + unsigned long mask =3D IOMMU_PAGE_MASK_4K; > unsigned long idx =3D ioba >> IOMMU_PAGE_SHIFT_4K; > unsigned long size =3D stt->window_size >> IOMMU_PAGE_SHIFT_4K; > =20 > - if ((ioba & mask) || (idx + npages > size)) > + if ((ioba & ~mask) || (idx + npages > size)) > return H_PARAMETER; > =20 > 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 =3D IOMMU_PAGE_MASK_4K | TCE_PCI_WRITE | TCE_PCI_REA= D; > + > + 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 =3D stt->pages[idx / TCES_PER_PAGE]; > + tbl =3D kvmppc_page_address(page); > + > + tbl[idx % TCES_PER_PAGE] =3D tce; > +} > +EXPORT_SYMBOL_GPL(kvmppc_tce_put); > =20 > /* 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 =3D kvmppc_find_table(vcpu, liobn); > long ret; > - unsigned long idx; > - struct page *page; > - u64 *tbl; > =20 > /* udbg_printf("H_PUT_TCE(): liobn=3D0x%lx ioba=3D0x%lx, tce=3D0x%lx\n"= , */ > /* liobn, ioba, tce); */ > @@ -99,13 +169,11 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigne= d long liobn, > if (ret !=3D H_SUCCESS) > return ret; > =20 > - idx =3D ioba >> IOMMU_PAGE_SHIFT_4K; > - page =3D stt->pages[idx / TCES_PER_PAGE]; > - tbl =3D (u64 *)page_address(page); > + ret =3D kvmppc_tce_validate(stt, tce); > + if (ret !=3D H_SUCCESS) > + return ret; > =20 > - /* FIXME: Need to validate the TCE itself */ > - /* udbg_printf("tce @ %p\n", &tbl[idx % TCES_PER_PAGE]); */ > - tbl[idx % TCES_PER_PAGE] =3D tce; > + kvmppc_tce_put(stt, ioba >> IOMMU_PAGE_SHIFT_4K, tce); > =20 > return H_SUCCESS; > } --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. 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