[PATCH kernel 4/4] KVM: PPC: Add support for 64bit TCE windows
Alexey Kardashevskiy
aik at ozlabs.ru
Wed Jan 27 14:29:25 AEDT 2016
On 01/25/2016 04:37 PM, David Gibson wrote:
> 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.
Agrh. I did this again :-/
>> +};
>> +
>> +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?
kvmppc_account_memlimit() below is some kind of bound, not enough?
>
>> 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 */
>
--
Alexey
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