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swiotlb: merge swiotlb-xen initialization into swiotlb

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Reuse the generic swiotlb initialization for xen-swiotlb.  For ARM/ARM64
this works trivially, while for x86 xen_swiotlb_fixup needs to be passed
as the remap argument to swiotlb_init_remap/swiotlb_init_late.

Note that the lower bound of the swiotlb size is changed to the smaller
IO_TLB_MIN_SLABS based value with this patch, but that is fine as the
2MB value used in Xen before was just an optimization and is not the
hard lower bound.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
This commit is contained in:
Christoph Hellwig 2022-03-14 07:58:45 +01:00
parent 7374153d29
commit 3f70356edf
6 changed files with 28 additions and 155 deletions
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21
arch/arm/xen/mm.c
View file

@ -23,22 +23,20 @@
#include <asm/xen/hypercall.h>
#include <asm/xen/interface.h>
unsigned long xen_get_swiotlb_free_pages(unsigned int order)
static gfp_t xen_swiotlb_gfp(void)
{
phys_addr_t base;
gfp_t flags = __GFP_NOWARN|__GFP_KSWAPD_RECLAIM;
u64 i;
for_each_mem_range(i, &base, NULL) {
if (base < (phys_addr_t)0xffffffff) {
if (IS_ENABLED(CONFIG_ZONE_DMA32))
flags |= __GFP_DMA32;
else
flags |= __GFP_DMA;
break;
return __GFP_DMA32;
return __GFP_DMA;
}
}
return __get_free_pages(flags, order);
return GFP_KERNEL;
}
static bool hypercall_cflush = false;
@ -140,10 +138,13 @@ static int __init xen_mm_init(void)
if (!xen_swiotlb_detect())
return 0;
rc = xen_swiotlb_init();
/* we can work with the default swiotlb */
if (rc < 0 && rc != -EEXIST)
return rc;
if (!io_tlb_default_mem.nslabs) {
rc = swiotlb_init_late(swiotlb_size_or_default(),
xen_swiotlb_gfp(), NULL);
if (rc < 0)
return rc;
}
cflush.op = 0;
cflush.a.dev_bus_addr = 0;

5
arch/x86/include/asm/xen/page.h
View file

@ -357,9 +357,4 @@ static inline bool xen_arch_need_swiotlb(struct device *dev,
return false;
}
static inline unsigned long xen_get_swiotlb_free_pages(unsigned int order)
{
return __get_free_pages(__GFP_NOWARN, order);
}
#endif /* _ASM_X86_XEN_PAGE_H */

20
arch/x86/kernel/pci-dma.c
View file

@ -72,15 +72,13 @@ static inline void __init pci_swiotlb_detect(void)
#endif /* CONFIG_SWIOTLB */
#ifdef CONFIG_SWIOTLB_XEN
static bool xen_swiotlb;
static void __init pci_xen_swiotlb_init(void)
{
if (!xen_initial_domain() && !x86_swiotlb_enable)
return;
x86_swiotlb_enable = true;
xen_swiotlb = true;
xen_swiotlb_init_early();
x86_swiotlb_flags |= SWIOTLB_ANY;
swiotlb_init_remap(true, x86_swiotlb_flags, xen_swiotlb_fixup);
dma_ops = &xen_swiotlb_dma_ops;
if (IS_ENABLED(CONFIG_PCI))
pci_request_acs();
@ -88,14 +86,16 @@ static void __init pci_xen_swiotlb_init(void)
int pci_xen_swiotlb_init_late(void)
{
int rc;
if (xen_swiotlb)
if (dma_ops == &xen_swiotlb_dma_ops)
return 0;
rc = xen_swiotlb_init();
if (rc)
return rc;
/* we can work with the default swiotlb */
if (!io_tlb_default_mem.nslabs) {
int rc = swiotlb_init_late(swiotlb_size_or_default(),
GFP_KERNEL, xen_swiotlb_fixup);
if (rc < 0)
return rc;
}
/* XXX: this switches the dma ops under live devices! */
dma_ops = &xen_swiotlb_dma_ops;

128
drivers/xen/swiotlb-xen.c
View file

@ -104,7 +104,7 @@ static int is_xen_swiotlb_buffer(struct device *dev, dma_addr_t dma_addr)
return 0;
}
static int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
{
int rc;
unsigned int order = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT);
@ -130,132 +130,6 @@ static int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
return 0;
}
enum xen_swiotlb_err {
XEN_SWIOTLB_UNKNOWN = 0,
XEN_SWIOTLB_ENOMEM,
XEN_SWIOTLB_EFIXUP
};
static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
{
switch (err) {
case XEN_SWIOTLB_ENOMEM:
return "Cannot allocate Xen-SWIOTLB buffer\n";
case XEN_SWIOTLB_EFIXUP:
return "Failed to get contiguous memory for DMA from Xen!\n"\
"You either: don't have the permissions, do not have"\
" enough free memory under 4GB, or the hypervisor memory"\
" is too fragmented!";
default:
break;
}
return "";
}
int xen_swiotlb_init(void)
{
enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;
unsigned long bytes = swiotlb_size_or_default();
unsigned long nslabs = bytes >> IO_TLB_SHIFT;
unsigned int order, repeat = 3;
int rc = -ENOMEM;
char *start;
if (io_tlb_default_mem.nslabs) {
pr_warn("swiotlb buffer already initialized\n");
return -EEXIST;
}
retry:
m_ret = XEN_SWIOTLB_ENOMEM;
order = get_order(bytes);
/*
* Get IO TLB memory from any location.
*/
#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
start = (void *)xen_get_swiotlb_free_pages(order);
if (start)
break;
order--;
}
if (!start)
goto exit;
if (order != get_order(bytes)) {
pr_warn("Warning: only able to allocate %ld MB for software IO TLB\n",
(PAGE_SIZE << order) >> 20);
nslabs = SLABS_PER_PAGE << order;
bytes = nslabs << IO_TLB_SHIFT;
}
/*
* And replace that memory with pages under 4GB.
*/
rc = xen_swiotlb_fixup(start, nslabs);
if (rc) {
free_pages((unsigned long)start, order);
m_ret = XEN_SWIOTLB_EFIXUP;
goto error;
}
rc = swiotlb_late_init_with_tbl(start, nslabs);
if (rc)
return rc;
return 0;
error:
if (nslabs > 1024 && repeat--) {
/* Min is 2MB */
nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE));
bytes = nslabs << IO_TLB_SHIFT;
pr_info("Lowering to %luMB\n", bytes >> 20);
goto retry;
}
exit:
pr_err("%s (rc:%d)\n", xen_swiotlb_error(m_ret), rc);
return rc;
}
#ifdef CONFIG_X86
void __init xen_swiotlb_init_early(void)
{
unsigned long bytes = swiotlb_size_or_default();
unsigned long nslabs = bytes >> IO_TLB_SHIFT;
unsigned int repeat = 3;
char *start;
int rc;
retry:
/*
* Get IO TLB memory from any location.
*/
start = memblock_alloc(PAGE_ALIGN(bytes),
IO_TLB_SEGSIZE << IO_TLB_SHIFT);
if (!start)
panic("%s: Failed to allocate %lu bytes\n",
__func__, PAGE_ALIGN(bytes));
/*
* And replace that memory with pages under 4GB.
*/
rc = xen_swiotlb_fixup(start, nslabs);
if (rc) {
memblock_free(start, PAGE_ALIGN(bytes));
if (nslabs > 1024 && repeat--) {
/* Min is 2MB */
nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE));
bytes = nslabs << IO_TLB_SHIFT;
pr_info("Lowering to %luMB\n", bytes >> 20);
goto retry;
}
panic("%s (rc:%d)", xen_swiotlb_error(XEN_SWIOTLB_EFIXUP), rc);
}
if (swiotlb_init_with_tbl(start, nslabs, SWIOTLB_VERBOSE))
panic("Cannot allocate SWIOTLB buffer");
}
#endif /* CONFIG_X86 */
static void *
xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
dma_addr_t *dma_handle, gfp_t flags,

1
include/xen/arm/page.h
View file

@ -115,6 +115,5 @@ static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
bool xen_arch_need_swiotlb(struct device *dev,
phys_addr_t phys,
dma_addr_t dev_addr);
unsigned long xen_get_swiotlb_free_pages(unsigned int order);
#endif /* _ASM_ARM_XEN_PAGE_H */

8
include/xen/swiotlb-xen.h
View file

@ -10,8 +10,12 @@ void xen_dma_sync_for_cpu(struct device *dev, dma_addr_t handle,
void xen_dma_sync_for_device(struct device *dev, dma_addr_t handle,
size_t size, enum dma_data_direction dir);
int xen_swiotlb_init(void);
void __init xen_swiotlb_init_early(void);
#ifdef CONFIG_SWIOTLB_XEN
int xen_swiotlb_fixup(void *buf, unsigned long nslabs);
#else
#define xen_swiotlb_fixup NULL
#endif
extern const struct dma_map_ops xen_swiotlb_dma_ops;
#endif /* __LINUX_SWIOTLB_XEN_H */