[RFC,2/5] iommu/vt-d: Add generic IO page table support
Commit Message
Add basic hook up code to implement generic IO page table framework.
Signed-off-by: Tina Zhang <tina.zhang@intel.com>
---
drivers/iommu/intel/Kconfig | 1 +
drivers/iommu/intel/iommu.c | 94 +++++++++++++++++++++++++++++++++++++
drivers/iommu/intel/iommu.h | 7 +++
drivers/iommu/io-pgtable.c | 3 ++
include/linux/io-pgtable.h | 2 +
5 files changed, 107 insertions(+)
Comments
On Mon, Nov 06, 2023 at 02:12:23AM -0500, Tina Zhang wrote:
> Add basic hook up code to implement generic IO page table framework.
>
> Signed-off-by: Tina Zhang <tina.zhang@intel.com>
> ---
> drivers/iommu/intel/Kconfig | 1 +
> drivers/iommu/intel/iommu.c | 94 +++++++++++++++++++++++++++++++++++++
> drivers/iommu/intel/iommu.h | 7 +++
> drivers/iommu/io-pgtable.c | 3 ++
> include/linux/io-pgtable.h | 2 +
> 5 files changed, 107 insertions(+)
If this is going to happen can we also convert vt-d to actually use
the io page table stuff directly and shuffle the code around so it is
structured like the rest of the io page table implementations?
Jason
Hi Jason,
> -----Original Message-----
> From: Jason Gunthorpe <jgg@ziepe.ca>
> Sent: Tuesday, November 7, 2023 3:32 AM
> To: Zhang, Tina <tina.zhang@intel.com>
> Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>; Tian, Kevin
> <kevin.tian@intel.com>; Lu Baolu <baolu.lu@linux.intel.com>; joro@8bytes.org;
> will@kernel.org; Liu, Yi L <yi.l.liu@intel.com>; virtualization@lists.linux-
> foundation.org; iommu@lists.linux.dev; linux-kernel@vger.kernel.org
> Subject: Re: [RFC PATCH 2/5] iommu/vt-d: Add generic IO page table support
>
> On Mon, Nov 06, 2023 at 02:12:23AM -0500, Tina Zhang wrote:
> > Add basic hook up code to implement generic IO page table framework.
> >
> > Signed-off-by: Tina Zhang <tina.zhang@intel.com>
> > ---
> > drivers/iommu/intel/Kconfig | 1 +
> > drivers/iommu/intel/iommu.c | 94
> > +++++++++++++++++++++++++++++++++++++
> > drivers/iommu/intel/iommu.h | 7 +++
> > drivers/iommu/io-pgtable.c | 3 ++
> > include/linux/io-pgtable.h | 2 +
> > 5 files changed, 107 insertions(+)
>
> If this is going to happen can we also convert vt-d to actually use the io page
> table stuff directly and shuffle the code around so it is structured like the rest of
> the io page table implementations?
Converting VT-d driver to use io page table involves much code change. I made a local version of it, and it didn't prove much benefit.
VT-d only supports one 1st-stage IO pgtable format and one 2nd-stage IO pgtable format. So, the current IO pgtable handling operations seems more efficient comparing to adding another layer callbacks in them.
We have a plan to add a new io_pgtable.c file under VT-d driver directory and use that file to collect IO pgtable related functions. But we want to hold on converting VT-d to use the IO page table directly unless we can see some benefits.
Regards,
-Tina
>
> Jason
On Thu, Nov 09, 2023 at 12:10:59AM +0000, Zhang, Tina wrote:
> > If this is going to happen can we also convert vt-d to actually use the io page
> > table stuff directly and shuffle the code around so it is structured like the rest of
> > the io page table implementations?
> Converting VT-d driver to use io page table involves much code
> change. I made a local version of it, and it didn't prove much
> benefit.
Well, it structures the code in a similar way to all the other
drivers, though I admit to having not looked closely at the io page
table stuff.
> VT-d only supports one 1st-stage IO pgtable format and one 2nd-stage
> IO pgtable format. So, the current IO pgtable handling operations
> seems more efficient comparing to adding another layer callbacks in
> them.
I would like to de-virtualize those callbacks, is is completely
pointless when we have per-format iommu_domain ops now.
Jason
@@ -15,6 +15,7 @@ config INTEL_IOMMU
select DMA_OPS
select IOMMU_API
select IOMMU_IOVA
+ select IOMMU_IO_PGTABLE
select NEED_DMA_MAP_STATE
select DMAR_TABLE
select SWIOTLB
@@ -23,6 +23,7 @@
#include <linux/syscore_ops.h>
#include <linux/tboot.h>
#include <uapi/linux/iommufd.h>
+#include <linux/io-pgtable.h>
#include "iommu.h"
#include "../dma-iommu.h"
@@ -67,6 +68,20 @@
#define LEVEL_STRIDE (9)
#define LEVEL_MASK (((u64)1 << LEVEL_STRIDE) - 1)
+#define io_pgtable_cfg_to_dmar_pgtable(x) \
+ container_of((x), struct dmar_io_pgtable, pgtbl_cfg)
+
+#define io_pgtable_to_dmar_pgtable(x) \
+ container_of((x), struct dmar_io_pgtable, iop)
+
+#define io_pgtable_to_dmar_domain(x) \
+ container_of(io_pgtable_to_dmar_pgtable(x), \
+ struct dmar_domain, dmar_iop)
+
+#define io_pgtable_ops_to_dmar_domain(x) \
+ container_of(io_pgtable_to_dmar_pgtable(io_pgtable_ops_to_pgtable(x)), \
+ struct dmar_domain, dmar_iop)
+
static inline int agaw_to_level(int agaw)
{
return agaw + 2;
@@ -5171,3 +5186,82 @@ int ecmd_submit_sync(struct intel_iommu *iommu, u8 ecmd, u64 oa, u64 ob)
return ret;
}
+
+static void flush_all(void *cookie)
+{
+}
+
+static void flush_walk(unsigned long iova, size_t size,
+ size_t granule, void *cookie)
+{
+}
+
+static void add_page(struct iommu_iotlb_gather *gather,
+ unsigned long iova, size_t granule,
+ void *cookie)
+{
+}
+
+static const struct iommu_flush_ops flush_ops = {
+ .tlb_flush_all = flush_all,
+ .tlb_flush_walk = flush_walk,
+ .tlb_add_page = add_page,
+};
+
+static void free_pgtable(struct io_pgtable *iop)
+{
+ struct dmar_domain *dmar_domain = io_pgtable_to_dmar_domain(iop);
+
+ if (dmar_domain->pgd) {
+ LIST_HEAD(freelist);
+
+ domain_unmap(dmar_domain, 0, DOMAIN_MAX_PFN(dmar_domain->gaw), &freelist);
+ put_pages_list(&freelist);
+ }
+}
+
+static int pgtable_map_pages(struct io_pgtable_ops *ops, unsigned long iova,
+ phys_addr_t paddr, size_t pgsize, size_t pgcount,
+ int iommu_prot, gfp_t gfp, size_t *mapped)
+{
+ struct dmar_domain *dmar_domain = io_pgtable_ops_to_dmar_domain(ops);
+
+ return intel_iommu_map_pages(&dmar_domain->domain, iova, paddr, pgsize,
+ pgcount, iommu_prot, gfp, mapped);
+}
+
+static size_t pgtable_unmap_pages(struct io_pgtable_ops *ops, unsigned long iova,
+ size_t pgsize, size_t pgcount,
+ struct iommu_iotlb_gather *gather)
+{
+ struct dmar_domain *dmar_domain = io_pgtable_ops_to_dmar_domain(ops);
+
+ return intel_iommu_unmap_pages(&dmar_domain->domain, iova, pgsize,
+ pgcount, gather);
+}
+
+static phys_addr_t pgtable_iova_to_phys(struct io_pgtable_ops *ops,
+ unsigned long iova)
+{
+ struct dmar_domain *dmar_domain = io_pgtable_ops_to_dmar_domain(ops);
+
+ return intel_iommu_iova_to_phys(&dmar_domain->domain, iova);
+}
+
+static struct io_pgtable *alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
+{
+ struct dmar_io_pgtable *pgtable = io_pgtable_cfg_to_dmar_pgtable(cfg);
+
+ pgtable->iop.ops.map_pages = pgtable_map_pages;
+ pgtable->iop.ops.unmap_pages = pgtable_unmap_pages;
+ pgtable->iop.ops.iova_to_phys = pgtable_iova_to_phys;
+
+ cfg->tlb = &flush_ops;
+
+ return &pgtable->iop;
+}
+
+struct io_pgtable_init_fns io_pgtable_intel_iommu_init_fns = {
+ .alloc = alloc_pgtable,
+ .free = free_pgtable,
+};
@@ -18,6 +18,7 @@
#include <linux/list.h>
#include <linux/iommu.h>
#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/io-pgtable.h>
#include <linux/dmar.h>
#include <linux/bitfield.h>
#include <linux/xarray.h>
@@ -579,6 +580,11 @@ struct iommu_domain_info {
* to VT-d spec, section 9.3 */
};
+struct dmar_io_pgtable {
+ struct io_pgtable_cfg pgtbl_cfg;
+ struct io_pgtable iop;
+};
+
struct dmar_domain {
int nid; /* node id */
struct xarray iommu_array; /* Attached IOMMU array */
@@ -633,6 +639,7 @@ struct dmar_domain {
struct iommu_domain domain; /* generic domain data structure for
iommu core */
+ struct dmar_io_pgtable dmar_iop;
};
/*
@@ -35,6 +35,9 @@ io_pgtable_init_table[IO_PGTABLE_NUM_FMTS] = {
#ifdef CONFIG_IOMMU_IO_PGTABLE_VIRT
[VIRT_IO_PGTABLE] = &io_pgtable_virt_init_fns,
#endif
+#ifdef CONFIG_INTEL_IOMMU
+ [INTEL_IOMMU] = &io_pgtable_intel_iommu_init_fns,
+#endif
};
struct io_pgtable_ops *alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,
@@ -20,6 +20,7 @@ enum io_pgtable_fmt {
APPLE_DART,
APPLE_DART2,
VIRT_IO_PGTABLE,
+ INTEL_IOMMU,
IO_PGTABLE_NUM_FMTS,
};
@@ -281,5 +282,6 @@ extern struct io_pgtable_init_fns io_pgtable_amd_iommu_v1_init_fns;
extern struct io_pgtable_init_fns io_pgtable_amd_iommu_v2_init_fns;
extern struct io_pgtable_init_fns io_pgtable_apple_dart_init_fns;
extern struct io_pgtable_init_fns io_pgtable_virt_init_fns;
+extern struct io_pgtable_init_fns io_pgtable_intel_iommu_init_fns;
#endif /* __IO_PGTABLE_H */