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. Signed-off-by: Alexey Kardashevskiy <[email protected]> --- arch/powerpc/include/asm/kvm_ppc.h | 4 ++ arch/powerpc/kvm/book3s_64_vio_hv.c | 89 ++++++++++++++++++++++++++++++++----- 2 files changed, 83 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h index c6ef05b..fcde896 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 6cf1ab3..f0fd84c 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)) @@ -64,7 +65,7 @@ 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; @@ -76,6 +77,79 @@ static long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt, 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) +{ + unsigned long mask = ((1ULL << IOMMU_PAGE_SHIFT_4K) - 1) & + ~(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 +159,6 @@ 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 = H_TOO_HARD; - 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 +170,11 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn, if (ret) 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) + 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 ret; } -- 2.4.0.rc3.8.gfb3e7d5 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
