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linux-stable/arch/powerpc/include/asm/iommu.h
Alexey Kardashevskiy cad32d9d42 KVM: PPC: Book3s: Retire H_PUT_TCE/etc real mode handlers 
LoPAPR defines guest visible IOMMU with hypercalls to use it -
H_PUT_TCE/etc. Implemented first on POWER7 where hypercalls would trap
in the KVM in the real mode (with MMU off). The problem with the real mode
is some memory is not available and some API usage crashed the host but
enabling MMU was an expensive operation.

The problems with the real mode handlers are:
1. Occasionally these cannot complete the request so the code is
copied+modified to work in the virtual mode, very little is shared;
2. The real mode handlers have to be linked into vmlinux to work;
3. An exception in real mode immediately reboots the machine.

If the small DMA window is used, the real mode handlers bring better
performance. However since POWER8, there has always been a bigger DMA
window which VMs use to map the entire VM memory to avoid calling
H_PUT_TCE. Such 1:1 mapping happens once and uses H_PUT_TCE_INDIRECT
(a bulk version of H_PUT_TCE) which virtual mode handler is even closer
to its real mode version.

On POWER9 hypercalls trap straight to the virtual mode so the real mode
handlers never execute on POWER9 and later CPUs.

So with the current use of the DMA windows and MMU improvements in
POWER9 and later, there is no point in duplicating the code.
The 32bit passed through devices may slow down but we do not have many
of these in practice. For example, with this applied, a 1Gbit ethernet
adapter still demostrates above 800Mbit/s of actual throughput.

This removes the real mode handlers from KVM and related code from
the powernv platform.

This updates the list of implemented hcalls in KVM-HV as the realmode
handlers are removed.

This changes ABI - kvmppc_h_get_tce() moves to the KVM module and
kvmppc_find_table() is static now.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220506053755.3820702-1-aik@ozlabs.ru
2022-05-19 00:44:01 +10:00

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2001 Mike Corrigan & Dave Engebretsen, IBM Corporation
* Rewrite, cleanup:
* Copyright (C) 2004 Olof Johansson <olof@lixom.net>, IBM Corporation
*/
#ifndef _ASM_IOMMU_H
#define _ASM_IOMMU_H
#ifdef __KERNEL__
#include <linux/compiler.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/dma-map-ops.h>
#include <linux/bitops.h>
#include <asm/machdep.h>
#include <asm/types.h>
#include <asm/pci-bridge.h>
#include <asm/asm-const.h>
#define IOMMU_PAGE_SHIFT_4K 12
#define IOMMU_PAGE_SIZE_4K (ASM_CONST(1) << IOMMU_PAGE_SHIFT_4K)
#define IOMMU_PAGE_MASK_4K (~((1 << IOMMU_PAGE_SHIFT_4K) - 1))
#define IOMMU_PAGE_ALIGN_4K(addr) ALIGN(addr, IOMMU_PAGE_SIZE_4K)
#define IOMMU_PAGE_SIZE(tblptr) (ASM_CONST(1) << (tblptr)->it_page_shift)
#define IOMMU_PAGE_MASK(tblptr) (~((1 << (tblptr)->it_page_shift) - 1))
#define IOMMU_PAGE_ALIGN(addr, tblptr) ALIGN(addr, IOMMU_PAGE_SIZE(tblptr))
/* Boot time flags */
extern int iommu_is_off;
extern int iommu_force_on;
struct iommu_table_ops {
/*
* When called with direction==DMA_NONE, it is equal to clear().
* uaddr is a linear map address.
*/
int (*set)(struct iommu_table *tbl,
long index, long npages,
unsigned long uaddr,
enum dma_data_direction direction,
unsigned long attrs);
#ifdef CONFIG_IOMMU_API
/*
* Exchanges existing TCE with new TCE plus direction bits;
* returns old TCE and DMA direction mask.
* @tce is a physical address.
*/
int (*xchg_no_kill)(struct iommu_table *tbl,
long index,
unsigned long *hpa,
enum dma_data_direction *direction);
void (*tce_kill)(struct iommu_table *tbl,
unsigned long index,
unsigned long pages);
__be64 *(*useraddrptr)(struct iommu_table *tbl, long index, bool alloc);
#endif
void (*clear)(struct iommu_table *tbl,
long index, long npages);
/* get() returns a physical address */
unsigned long (*get)(struct iommu_table *tbl, long index);
void (*flush)(struct iommu_table *tbl);
void (*free)(struct iommu_table *tbl);
};
/* These are used by VIO */
extern struct iommu_table_ops iommu_table_lpar_multi_ops;
extern struct iommu_table_ops iommu_table_pseries_ops;
/*
* IOMAP_MAX_ORDER defines the largest contiguous block
* of dma space we can get. IOMAP_MAX_ORDER = 13
* allows up to 2**12 pages (4096 * 4096) = 16 MB
*/
#define IOMAP_MAX_ORDER 13
#define IOMMU_POOL_HASHBITS 2
#define IOMMU_NR_POOLS (1 << IOMMU_POOL_HASHBITS)
struct iommu_pool {
unsigned long start;
unsigned long end;
unsigned long hint;
spinlock_t lock;
} ____cacheline_aligned_in_smp;
struct iommu_table {
unsigned long it_busno; /* Bus number this table belongs to */
unsigned long it_size; /* Size of iommu table in entries */
unsigned long it_indirect_levels;
unsigned long it_level_size;
unsigned long it_allocated_size;
unsigned long it_offset; /* Offset into global table */
unsigned long it_base; /* mapped address of tce table */
unsigned long it_index; /* which iommu table this is */
unsigned long it_type; /* type: PCI or Virtual Bus */
unsigned long it_blocksize; /* Entries in each block (cacheline) */
unsigned long poolsize;
unsigned long nr_pools;
struct iommu_pool large_pool;
struct iommu_pool pools[IOMMU_NR_POOLS];
unsigned long *it_map; /* A simple allocation bitmap for now */
unsigned long it_page_shift;/* table iommu page size */
struct list_head it_group_list;/* List of iommu_table_group_link */
__be64 *it_userspace; /* userspace view of the table */
struct iommu_table_ops *it_ops;
struct kref it_kref;
int it_nid;
unsigned long it_reserved_start; /* Start of not-DMA-able (MMIO) area */
unsigned long it_reserved_end;
};
#define IOMMU_TABLE_USERSPACE_ENTRY_RO(tbl, entry) \
((tbl)->it_ops->useraddrptr((tbl), (entry), false))
#define IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry) \
((tbl)->it_ops->useraddrptr((tbl), (entry), true))
/* Pure 2^n version of get_order */
static inline __attribute_const__
int get_iommu_order(unsigned long size, struct iommu_table *tbl)
{
return __ilog2((size - 1) >> tbl->it_page_shift) + 1;
}
struct scatterlist;
#ifdef CONFIG_PPC64
static inline void set_iommu_table_base(struct device *dev,
struct iommu_table *base)
{
dev->archdata.iommu_table_base = base;
}
static inline void *get_iommu_table_base(struct device *dev)
{
return dev->archdata.iommu_table_base;
}
extern int dma_iommu_dma_supported(struct device *dev, u64 mask);
extern struct iommu_table *iommu_tce_table_get(struct iommu_table *tbl);
extern int iommu_tce_table_put(struct iommu_table *tbl);
/* Initializes an iommu_table based in values set in the passed-in
* structure
*/
extern struct iommu_table *iommu_init_table(struct iommu_table *tbl,
int nid, unsigned long res_start, unsigned long res_end);
bool iommu_table_in_use(struct iommu_table *tbl);
#define IOMMU_TABLE_GROUP_MAX_TABLES 2
struct iommu_table_group;
struct iommu_table_group_ops {
unsigned long (*get_table_size)(
__u32 page_shift,
__u64 window_size,
__u32 levels);
long (*create_table)(struct iommu_table_group *table_group,
int num,
__u32 page_shift,
__u64 window_size,
__u32 levels,
struct iommu_table **ptbl);
long (*set_window)(struct iommu_table_group *table_group,
int num,
struct iommu_table *tblnew);
long (*unset_window)(struct iommu_table_group *table_group,
int num);
/* Switch ownership from platform code to external user (e.g. VFIO) */
void (*take_ownership)(struct iommu_table_group *table_group);
/* Switch ownership from external user (e.g. VFIO) back to core */
void (*release_ownership)(struct iommu_table_group *table_group);
};
struct iommu_table_group_link {
struct list_head next;
struct rcu_head rcu;
struct iommu_table_group *table_group;
};
struct iommu_table_group {
/* IOMMU properties */
__u32 tce32_start;
__u32 tce32_size;
__u64 pgsizes; /* Bitmap of supported page sizes */
__u32 max_dynamic_windows_supported;
__u32 max_levels;
struct iommu_group *group;
struct iommu_table *tables[IOMMU_TABLE_GROUP_MAX_TABLES];
struct iommu_table_group_ops *ops;
};
#ifdef CONFIG_IOMMU_API
extern void iommu_register_group(struct iommu_table_group *table_group,
int pci_domain_number, unsigned long pe_num);
extern int iommu_add_device(struct iommu_table_group *table_group,
struct device *dev);
extern void iommu_del_device(struct device *dev);
extern long iommu_tce_xchg(struct mm_struct *mm, struct iommu_table *tbl,
unsigned long entry, unsigned long *hpa,
enum dma_data_direction *direction);
extern long iommu_tce_xchg_no_kill(struct mm_struct *mm,
struct iommu_table *tbl,
unsigned long entry, unsigned long *hpa,
enum dma_data_direction *direction);
extern void iommu_tce_kill(struct iommu_table *tbl,
unsigned long entry, unsigned long pages);
#else
static inline void iommu_register_group(struct iommu_table_group *table_group,
int pci_domain_number,
unsigned long pe_num)
{
}
static inline int iommu_add_device(struct iommu_table_group *table_group,
struct device *dev)
{
return 0;
}
static inline void iommu_del_device(struct device *dev)
{
}
#endif /* !CONFIG_IOMMU_API */
u64 dma_iommu_get_required_mask(struct device *dev);
#else
static inline void *get_iommu_table_base(struct device *dev)
{
return NULL;
}
static inline int dma_iommu_dma_supported(struct device *dev, u64 mask)
{
return 0;
}
#endif /* CONFIG_PPC64 */
extern int ppc_iommu_map_sg(struct device *dev, struct iommu_table *tbl,
struct scatterlist *sglist, int nelems,
unsigned long mask,
enum dma_data_direction direction,
unsigned long attrs);
extern void ppc_iommu_unmap_sg(struct iommu_table *tbl,
struct scatterlist *sglist,
int nelems,
enum dma_data_direction direction,
unsigned long attrs);
extern void *iommu_alloc_coherent(struct device *dev, struct iommu_table *tbl,
size_t size, dma_addr_t *dma_handle,
unsigned long mask, gfp_t flag, int node);
extern void iommu_free_coherent(struct iommu_table *tbl, size_t size,
void *vaddr, dma_addr_t dma_handle);
extern dma_addr_t iommu_map_page(struct device *dev, struct iommu_table *tbl,
struct page *page, unsigned long offset,
size_t size, unsigned long mask,
enum dma_data_direction direction,
unsigned long attrs);
extern void iommu_unmap_page(struct iommu_table *tbl, dma_addr_t dma_handle,
size_t size, enum dma_data_direction direction,
unsigned long attrs);
void __init iommu_init_early_pSeries(void);
extern void iommu_init_early_dart(struct pci_controller_ops *controller_ops);
extern void iommu_init_early_pasemi(void);
#if defined(CONFIG_PPC64) && defined(CONFIG_PM)
static inline void iommu_restore(void)
{
if (ppc_md.iommu_restore)
ppc_md.iommu_restore();
}
#endif
/* The API to support IOMMU operations for VFIO */
extern int iommu_tce_check_ioba(unsigned long page_shift,
unsigned long offset, unsigned long size,
unsigned long ioba, unsigned long npages);
extern int iommu_tce_check_gpa(unsigned long page_shift,
unsigned long gpa);
#define iommu_tce_clear_param_check(tbl, ioba, tce_value, npages) \
(iommu_tce_check_ioba((tbl)->it_page_shift, \
(tbl)->it_offset, (tbl)->it_size, \
(ioba), (npages)) || (tce_value))
#define iommu_tce_put_param_check(tbl, ioba, gpa) \
(iommu_tce_check_ioba((tbl)->it_page_shift, \
(tbl)->it_offset, (tbl)->it_size, \
(ioba), 1) || \
iommu_tce_check_gpa((tbl)->it_page_shift, (gpa)))
extern void iommu_flush_tce(struct iommu_table *tbl);
extern int iommu_take_ownership(struct iommu_table *tbl);
extern void iommu_release_ownership(struct iommu_table *tbl);
extern enum dma_data_direction iommu_tce_direction(unsigned long tce);
extern unsigned long iommu_direction_to_tce_perm(enum dma_data_direction dir);
#ifdef CONFIG_PPC_CELL_NATIVE
extern bool iommu_fixed_is_weak;
#else
#define iommu_fixed_is_weak false
#endif
extern const struct dma_map_ops dma_iommu_ops;
#endif /* __KERNEL__ */
#endif /* _ASM_IOMMU_H */
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