On Wed, Jan 27, 2016 at 02:29:25PM +1100, Alexey Kardashevskiy wrote:

On 01/25/2016 04:37 PM, David Gibson wrote:

quoted

On Thu, Jan 21, 2016 at 07:15:26PM +1100, Alexey Kardashevskiy wrote:

quoted

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 <redacted>
---
 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 :-/

quoted

quoted

+};
+
+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.
+
+@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?

Ah, yes, that should be enough.

Sorry, missed that.

-- 
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