[PATCH kernel 4/4] KVM: PPC: Add support for 64bit TCE windows
David Gibson
david at gibson.dropbear.id.au
Mon Jan 25 16:37:27 AEDT 2016
On Thu, Jan 21, 2016 at 07:15:26PM +1100, Alexey Kardashevskiy wrote:
> The existing KVM_CREATE_SPAPR_TCE only supports 32bit windows which is not
> enough for directly mapped windows as the guest can get more than 4GB.
>
> This adds KVM_CREATE_SPAPR_TCE_64 ioctl and advertises it
> via KVM_CAP_SPAPR_TCE_64 capability.
>
> Since 64bit windows are to support Dynamic DMA windows (DDW), let's add
> @bus_offset and @page_shift which are also required by DDW.
>
> Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
> ---
> Documentation/virtual/kvm/api.txt | 32 ++++++++++++++++++++++++++++++++
> arch/powerpc/include/asm/kvm_ppc.h | 2 +-
> arch/powerpc/include/uapi/asm/kvm.h | 9 +++++++++
> arch/powerpc/kvm/book3s_64_vio.c | 10 +++++++---
> arch/powerpc/kvm/powerpc.c | 25 ++++++++++++++++++++++++-
> include/uapi/linux/kvm.h | 2 ++
> 6 files changed, 75 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> index da39435..d1c5655 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -3060,6 +3060,38 @@ an implementation for these despite the in kernel acceleration.
>
> This capability is always enabled.
>
> +4.96 KVM_CREATE_SPAPR_TCE_64
> +
> +Capability: KVM_CAP_SPAPR_TCE_64
> +Architectures: powerpc
> +Type: vm ioctl
> +Parameters: struct kvm_create_spapr_tce_64 (in)
> +Returns: file descriptor for manipulating the created TCE table
> +
> +This is an extension for KVM_CAP_SPAPR_TCE which only supports 32bit
> +windows, described in 4.62 KVM_CREATE_SPAPR_TCE
> +
> +This capability uses extended struct in ioctl interface:
> +
> +/* for KVM_CAP_SPAPR_TCE_64 */
> +struct kvm_create_spapr_tce_64 {
> + __u64 liobn;
> + __u32 page_shift;
> + __u64 offset; /* in pages */
> + __u64 size; /* in pages */
> + __u32 flags;
Best to move page_shift after offset and size, so the structure
doesn't get an alignment gap.
> +};
> +
> +The aim of extension is to support an additional bigger DMA window with
> +a variable page size.
> +KVM_CREATE_SPAPR_TCE_64 receives a 64bit window size, an IOMMU page shift and
> +a bus offset of the corresponding DMA window, @size and @offset are numbers
> +of IOMMU pages.
> +
> + at flags are not used at the moment.
> +
> +The rest of functionality is identical to KVM_CREATE_SPAPR_TCE.
> +
> 5. The kvm_run structure
> ------------------------
>
> diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
> index 4cadee5..6e4d1dc 100644
> --- a/arch/powerpc/include/asm/kvm_ppc.h
> +++ b/arch/powerpc/include/asm/kvm_ppc.h
> @@ -165,7 +165,7 @@ extern void kvmppc_map_vrma(struct kvm_vcpu *vcpu,
> 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);
> + struct kvm_create_spapr_tce_64 *args);
> extern struct kvmppc_spapr_tce_table *kvmppc_find_table(
> struct kvm_vcpu *vcpu, unsigned long liobn);
> extern long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt,
> diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
> index ab4d473..9c8b4cbc 100644
> --- a/arch/powerpc/include/uapi/asm/kvm.h
> +++ b/arch/powerpc/include/uapi/asm/kvm.h
> @@ -333,6 +333,15 @@ struct kvm_create_spapr_tce {
> __u32 window_size;
> };
>
> +/* for KVM_CAP_SPAPR_TCE_64 */
> +struct kvm_create_spapr_tce_64 {
> + __u64 liobn;
> + __u32 page_shift;
> + __u64 offset; /* in pages */
> + __u64 size; /* in pages */
> + __u32 flags;
> +};
> +
> /* for KVM_ALLOCATE_RMA */
> struct kvm_allocate_rma {
> __u64 rma_size;
> diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
> index 85ee572..5479446 100644
> --- a/arch/powerpc/kvm/book3s_64_vio.c
> +++ b/arch/powerpc/kvm/book3s_64_vio.c
> @@ -144,20 +144,23 @@ static const struct file_operations kvm_spapr_tce_fops = {
> };
>
> long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
> - struct kvm_create_spapr_tce *args)
> + struct kvm_create_spapr_tce_64 *args)
> {
> struct kvmppc_spapr_tce_table *stt = NULL;
> unsigned long npages, size;
> int ret = -ENOMEM;
> int i;
>
> + if (!args->size)
> + return -EINVAL;
> +
> /* Check this LIOBN hasn't been previously allocated */
> list_for_each_entry(stt, &kvm->arch.spapr_tce_tables, list) {
> if (stt->liobn == args->liobn)
> return -EBUSY;
> }
>
> - size = args->window_size >> IOMMU_PAGE_SHIFT_4K;
> + size = args->size;
Doesn't this need some kind of bounds on the allowed size?
> npages = kvmppc_stt_npages(size);
> ret = kvmppc_account_memlimit(npages, true);
> if (ret) {
> @@ -171,7 +174,8 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
> goto fail;
>
> stt->liobn = args->liobn;
> - stt->page_shift = IOMMU_PAGE_SHIFT_4K;
> + stt->page_shift = args->page_shift;
> + stt->offset = args->offset;
> stt->size = size;
> stt->kvm = kvm;
>
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index 164735c..2b0fe92 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -33,6 +33,7 @@
> #include <asm/tlbflush.h>
> #include <asm/cputhreads.h>
> #include <asm/irqflags.h>
> +#include <asm/iommu.h>
> #include "timing.h"
> #include "irq.h"
> #include "../mm/mmu_decl.h"
> @@ -509,6 +510,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
>
> #ifdef CONFIG_PPC_BOOK3S_64
> case KVM_CAP_SPAPR_TCE:
> + case KVM_CAP_SPAPR_TCE_64:
> case KVM_CAP_PPC_ALLOC_HTAB:
> case KVM_CAP_PPC_RTAS:
> case KVM_CAP_PPC_FIXUP_HCALL:
> @@ -1334,13 +1336,34 @@ long kvm_arch_vm_ioctl(struct file *filp,
> break;
> }
> #ifdef CONFIG_PPC_BOOK3S_64
> + case KVM_CREATE_SPAPR_TCE_64: {
> + struct kvm_create_spapr_tce_64 create_tce_64;
> +
> + r = -EFAULT;
> + if (copy_from_user(&create_tce_64, argp, sizeof(create_tce_64)))
> + goto out;
> + if (create_tce_64.flags) {
> + r = -EINVAL;
> + goto out;
> + }
> + r = kvm_vm_ioctl_create_spapr_tce(kvm, &create_tce_64);
> + goto out;
> + }
> case KVM_CREATE_SPAPR_TCE: {
> struct kvm_create_spapr_tce create_tce;
> + struct kvm_create_spapr_tce_64 create_tce_64;
>
> r = -EFAULT;
> if (copy_from_user(&create_tce, argp, sizeof(create_tce)))
> goto out;
> - r = kvm_vm_ioctl_create_spapr_tce(kvm, &create_tce);
> +
> + create_tce_64.liobn = create_tce.liobn;
> + create_tce_64.page_shift = IOMMU_PAGE_SHIFT_4K;
> + create_tce_64.offset = 0;
> + create_tce_64.size = create_tce.window_size >>
> + IOMMU_PAGE_SHIFT_4K;
> + create_tce_64.flags = 0;
> + r = kvm_vm_ioctl_create_spapr_tce(kvm, &create_tce_64);
> goto out;
> }
> case KVM_PPC_GET_SMMU_INFO: {
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 8ce5f64..b06208b 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -1143,6 +1143,8 @@ struct kvm_s390_ucas_mapping {
> /* Available with KVM_CAP_PPC_ALLOC_HTAB */
> #define KVM_PPC_ALLOCATE_HTAB _IOWR(KVMIO, 0xa7, __u32)
> #define KVM_CREATE_SPAPR_TCE _IOW(KVMIO, 0xa8, struct kvm_create_spapr_tce)
> +#define KVM_CREATE_SPAPR_TCE_64 _IOW(KVMIO, 0xa8, \
> + struct kvm_create_spapr_tce_64)
> /* Available with KVM_CAP_RMA */
> #define KVM_ALLOCATE_RMA _IOR(KVMIO, 0xa9, struct kvm_allocate_rma)
> /* Available with KVM_CAP_PPC_HTAB_FD */
--
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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