path: root/arch/sparc/kernel/hvapi.c
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authorDavid S. Miller <davem@davemloft.net>2016-11-18 11:17:10 -0800
committerDavid S. Miller <davem@davemloft.net>2016-11-18 11:17:10 -0800
commit49cc0c43d0d60ba8ca1cd754921bb50119d42940 (patch)
tree9aa3298173c5cc35683d8e01259e856e1ae84921 /arch/sparc/kernel/hvapi.c
parentsparc64: fix compile warning section mismatch in find_node() (diff)
parentsparc64: Enable 64-bit DMA (diff)
Merge branch 'sun4v-64bit-DMA'
Tushar Dave says: ==================== sparc: Enable sun4v hypervisor PCI IOMMU v2 APIs and ATU ATU (Address Translation Unit) is a new IOMMU in SPARC supported with sun4v hypervisor PCI IOMMU v2 APIs. Current SPARC IOMMU supports only 32bit address ranges and one TSB per PCIe root complex that has a 2GB per root complex DVMA space limit. The limit has become a scalability bottleneck nowadays that a typical 10G/40G NIC can consume 500MB DVMA space per instance. When DVMA resource is exhausted, devices will not be usable since the driver can't allocate DVMA. For example, we recently experienced legacy IOMMU limitation while using i40e driver in system with large number of CPUs (e.g. 128). Four ports of i40e, each request 128 QP (Queue Pairs). Each queue has 512 (default) descriptors. So considering only RX queues (because RX premap DMA buffers), i40e takes 4*128*512 number of DMA entries in IOMMU table. Legacy IOMMU can have at max (2G/8K)- 1 entries available in table. So bringing up four instance of i40e alone saturate existing IOMMU resource. ATU removes bottleneck by allowing guest os to create IOTSB of size 32G (or more) with 64bit address ranges available in ATU HW. 32G is more than enough DVMA space to be shared by all PCIe devices under root complex contrast to 2G space provided by legacy IOMMU. ATU allows PCIe devices to use 64bit DMA addressing. Devices which choose to use 32bit DMA mask will continue to work with the existing legacy IOMMU. The patch set is tested on sun4v (T1000, T2000, T3, T4, T5, T7, S7) and sun4u SPARC. Thanks. -Tushar v2->v3: - Patch #5 addresses comment by Joe Perches. -- use %s, __func__ instead of embedding the function name. v1->v2: - Patch #2 addresses comments by Dave M. -- use page allocator to allocate IOTSB. -- use true/false with boolean variables. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc/kernel/hvapi.c')
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/sparc/kernel/hvapi.c b/arch/sparc/kernel/hvapi.c
index 662500fa555f..267731234ce8 100644
--- a/arch/sparc/kernel/hvapi.c
+++ b/arch/sparc/kernel/hvapi.c
@@ -39,6 +39,7 @@ static struct api_info api_table[] = {
{ .group = HV_GRP_SDIO, },
{ .group = HV_GRP_SDIO_ERR, },
{ .group = HV_GRP_REBOOT_DATA, },
+ { .group = HV_GRP_ATU, .flags = FLAG_PRE_API },
{ .group = HV_GRP_NIAG_PERF, .flags = FLAG_PRE_API },
{ .group = HV_GRP_FIRE_PERF, },
{ .group = HV_GRP_N2_CPU, },