KVM: PPC: Add @page_shift to kvmppc_spapr_tce_table

At the moment the kvmppc_spapr_tce_table struct can only describe
4GB windows and handle fixed size (4K) pages. Dynamic DMA windows
support more so these limits need to be extended.

This replaces window_size (in bytes, 4GB max) with page_shift (32bit)
and size (64bit, in pages).

This should cause no behavioural change as this is changing
the internal structures only - the user interface still only
allows one to create a 32-bit table with 4KiB pages at this stage.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 21 insertions, 22 deletions

diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
index 94c8e7e9b58c..61cbc449d0a8 100644
--- a/arch/powerpc/kvm/book3s_64_vio.c
+++ b/arch/powerpc/kvm/book3s_64_vio.c
@@ -40,10 +40,9 @@
 #include <asm/iommu.h>
 #include <asm/tce.h>
 
-static unsigned long kvmppc_tce_pages(unsigned long window_size)
+static unsigned long kvmppc_tce_pages(unsigned long iommu_pages)
 {
-        return ALIGN((window_size >> IOMMU_PAGE_SHIFT_4K)
-                     * sizeof(u64), PAGE_SIZE) / PAGE_SIZE;
+        return ALIGN(iommu_pages * sizeof(u64), PAGE_SIZE) / PAGE_SIZE;
 }
 
 static unsigned long kvmppc_stt_pages(unsigned long tce_pages)
@@ -95,8 +94,7 @@ static void release_spapr_tce_table(struct rcu_head *head)
 {
         struct kvmppc_spapr_tce_table *stt = container_of(head,
                         struct kvmppc_spapr_tce_table, rcu);
-        int i;
-        unsigned long npages = kvmppc_tce_pages(stt->window_size);
+        unsigned long i, npages = kvmppc_tce_pages(stt->size);
 
         for (i = 0; i < npages; i++)
                 __free_page(stt->pages[i]);
@@ -109,7 +107,7 @@ static int kvm_spapr_tce_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
         struct kvmppc_spapr_tce_table *stt = vma->vm_file->private_data;
         struct page *page;
 
-        if (vmf->pgoff >= kvmppc_tce_pages(stt->window_size))
+        if (vmf->pgoff >= kvmppc_tce_pages(stt->size))
                 return VM_FAULT_SIGBUS;
 
         page = stt->pages[vmf->pgoff];
@@ -137,7 +135,7 @@ static int kvm_spapr_tce_release(struct inode *inode, struct file *filp)
         kvm_put_kvm(stt->kvm);
 
         kvmppc_account_memlimit(
-                kvmppc_stt_pages(kvmppc_tce_pages(stt->window_size)), false);
+                kvmppc_stt_pages(kvmppc_tce_pages(stt->size)), false);
         call_rcu(&stt->rcu, release_spapr_tce_table);
 
         return 0;
@@ -152,7 +150,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
                                    struct kvm_create_spapr_tce *args)
 {
         struct kvmppc_spapr_tce_table *stt = NULL;
-        unsigned long npages;
+        unsigned long npages, size;
         int ret = -ENOMEM;
         int i;
 
@@ -162,7 +160,8 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
                         return -EBUSY;
         }
 
-        npages = kvmppc_tce_pages(args->window_size);
+        size = args->window_size >> IOMMU_PAGE_SHIFT_4K;
+        npages = kvmppc_tce_pages(size);
         ret = kvmppc_account_memlimit(kvmppc_stt_pages(npages), true);
         if (ret) {
                 stt = NULL;
@@ -175,7 +174,8 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
                 goto fail;
 
         stt->liobn = args->liobn;
-        stt->window_size = args->window_size;
+        stt->page_shift = IOMMU_PAGE_SHIFT_4K;
+        stt->size = size;
         stt->kvm = kvm;
 
         for (i = 0; i < npages; i++) {
@@ -218,7 +218,7 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
         if (!stt)
                 return H_TOO_HARD;
 
-        entry = ioba >> IOMMU_PAGE_SHIFT_4K;
+        entry = ioba >> stt->page_shift;
         /*
          * SPAPR spec says that the maximum size of the list is 512 TCEs
          * so the whole table fits in 4K page
diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
index 0486aa2329ee..c786a58c28a7 100644
--- a/arch/powerpc/kvm/book3s_64_vio_hv.c
+++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
@@ -72,11 +72,10 @@ EXPORT_SYMBOL_GPL(kvmppc_find_table);
 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;
-        unsigned long idx = ioba >> IOMMU_PAGE_SHIFT_4K;
-        unsigned long size = stt->window_size >> IOMMU_PAGE_SHIFT_4K;
+        unsigned long mask = (1ULL << stt->page_shift) - 1;
+        unsigned long idx = ioba >> stt->page_shift;
 
-        if ((ioba & mask) || (idx + npages > size) || (idx + npages < idx))
+        if ((ioba & mask) || (idx + npages > stt->size) || (idx + npages < idx))
                 return H_PARAMETER;
 
         return H_SUCCESS;
@@ -96,8 +95,8 @@ EXPORT_SYMBOL_GPL(kvmppc_ioba_validate);
  */
 long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt, unsigned long tce)
 {
-        unsigned long mask =
-                        ~(IOMMU_PAGE_MASK_4K | TCE_PCI_WRITE | TCE_PCI_READ);
+        unsigned long page_mask = ~((1ULL << stt->page_shift) - 1);
+        unsigned long mask = ~(page_mask | TCE_PCI_WRITE | TCE_PCI_READ);
 
         if (tce & mask)
                 return H_PARAMETER;
@@ -198,7 +197,7 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
         if (ret != H_SUCCESS)
                 return ret;
 
-        kvmppc_tce_put(stt, ioba >> IOMMU_PAGE_SHIFT_4K, tce);
+        kvmppc_tce_put(stt, ioba >> stt->page_shift, tce);
 
         return H_SUCCESS;
 }
@@ -244,7 +243,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
         if (!stt)
                 return H_TOO_HARD;
 
-        entry = ioba >> IOMMU_PAGE_SHIFT_4K;
+        entry = ioba >> stt->page_shift;
         /*
          * The spec says that the maximum size of the list is 512 TCEs
          * so the whole table addressed resides in 4K page
@@ -313,8 +312,8 @@ long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu,
         if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ))
                 return H_PARAMETER;
 
-        for (i = 0; i < npages; ++i, ioba += IOMMU_PAGE_SIZE_4K)
-                kvmppc_tce_put(stt, ioba >> IOMMU_PAGE_SHIFT_4K, tce_value);
+        for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
+                kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);
 
         return H_SUCCESS;
 }
@@ -336,7 +335,7 @@ long kvmppc_h_get_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
         if (ret != H_SUCCESS)
                 return ret;
 
-        idx = ioba >> IOMMU_PAGE_SHIFT_4K;
+        idx = ioba >> stt->page_shift;
         page = stt->pages[idx / TCES_PER_PAGE];
         tbl = (u64 *)page_address(page);