KVM: PPC: Add @offset to kvmppc_spapr_tce_table

This enables userspace view of TCE tables to start from non-zero offset
on a bus. This will be used for huge DMA windows.

This only changes the internal structure, the user interface needs to
change in order to use an offset.

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>

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index edf66f77049868c4049c6708c90896e5d71fd2cb..2e7c79101652ef863ee049da91b6047a193a440b 100644 (file)
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -184,6 +184,7 @@ struct kvmppc_spapr_tce_table {
        u64 liobn;
        struct rcu_head rcu;
        u32 page_shift;
+       u64 offset;             /* in pages */
        u64 size;               /* window size in pages */
        struct page *pages[0];
 };

diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
index c786a58c28a7761647c06df0835065a91796d598..44be73e6aa26b6563d1cc4cc91e1a332a84271c3 100644 (file)
--- a/arch/powerpc/kvm/book3s_64_vio_hv.c
+++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
@@ -75,7 +75,9 @@ long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt,
        unsigned long mask = (1ULL << stt->page_shift) - 1;
        unsigned long idx = ioba >> stt->page_shift;
 
-       if ((ioba & mask) || (idx + npages > stt->size) || (idx + npages < idx))
+       if ((ioba & mask) || (idx < stt->offset) ||
+                       (idx - stt->offset + npages > stt->size) ||
+                       (idx + npages < idx))
                return H_PARAMETER;
 
        return H_SUCCESS;
@@ -147,6 +149,7 @@ void kvmppc_tce_put(struct kvmppc_spapr_tce_table *stt,
        struct page *page;
        u64 *tbl;
 
+       idx -= stt->offset;
        page = stt->pages[idx / TCES_PER_PAGE];
        tbl = kvmppc_page_address(page);
 
@@ -335,7 +338,7 @@ long kvmppc_h_get_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
        if (ret != H_SUCCESS)
                return ret;
 
-       idx = ioba >> stt->page_shift;
+       idx = (ioba >> stt->page_shift) - stt->offset;
        page = stt->pages[idx / TCES_PER_PAGE];
        tbl = (u64 *)page_address(page);