[PATCH RFC v1 5/6] xen-swiotlb: convert variables to arrays

Dongli Zhang
2021-02-03T23:41:47Z

This patch converts several xen-swiotlb related variables to arrays, in
order to maintain stat/status for different swiotlb buffers. Here are
variables involved:

- xen_io_tlb_start and xen_io_tlb_end
- xen_io_tlb_nslabs
- MAX_DMA_BITS

There is no functional change and this is to prepare to enable 64-bit
xen-swiotlb.

Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
---
drivers/xen/swiotlb-xen.c | 75 +++++++++++++++++++++------------------
1 file changed, 40 insertions(+), 35 deletions(-)

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 662638093542..e18cae693cdc 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -39,15 +39,17 @@
#include <asm/xen/page-coherent.h>

#include <trace/events/swiotlb.h>
-#define MAX_DMA_BITS 32
/*
* Used to do a quick range check in swiotlb_tbl_unmap_single and
* swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
* API.
*/

-static char *xen_io_tlb_start, *xen_io_tlb_end;
-static unsigned long xen_io_tlb_nslabs;
+static char *xen_io_tlb_start[SWIOTLB_MAX], *xen_io_tlb_end[SWIOTLB_MAX];
+static unsigned long xen_io_tlb_nslabs[SWIOTLB_MAX];
+
+static int max_dma_bits[] = {32, 64};
+
/*
* Quick lookup value of the bus address of the IOTLB.
*/
@@ -112,8 +114,8 @@ static int is_xen_swiotlb_buffer(struct device *dev, dma_addr_t dma_addr)
* in our domain. Therefore _only_ check address within our domain.
*/
if (pfn_valid(PFN_DOWN(paddr))) {
- return paddr >= virt_to_phys(xen_io_tlb_start) &&
- paddr < virt_to_phys(xen_io_tlb_end);
+ return paddr >= virt_to_phys(xen_io_tlb_start[SWIOTLB_LO]) &&
+ paddr < virt_to_phys(xen_io_tlb_end[SWIOTLB_LO]);
}
return 0;
}
@@ -137,7 +139,7 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
p + (i << IO_TLB_SHIFT),
get_order(slabs << IO_TLB_SHIFT),
dma_bits, &dma_handle);
- } while (rc && dma_bits++ < MAX_DMA_BITS);
+ } while (rc && dma_bits++ < max_dma_bits[SWIOTLB_LO]);
if (rc)
return rc;

@@ -148,12 +150,13 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
static unsigned long xen_set_nslabs(unsigned long nr_tbl)
{
if (!nr_tbl) {
- xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
- xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
+ xen_io_tlb_nslabs[SWIOTLB_LO] = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
+ xen_io_tlb_nslabs[SWIOTLB_LO] = ALIGN(xen_io_tlb_nslabs[SWIOTLB_LO],
+ IO_TLB_SEGSIZE);
} else
- xen_io_tlb_nslabs = nr_tbl;
+ xen_io_tlb_nslabs[SWIOTLB_LO] = nr_tbl;

- return xen_io_tlb_nslabs << IO_TLB_SHIFT;
+ return xen_io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT;
}

enum xen_swiotlb_err {
@@ -184,16 +187,16 @@ int __ref xen_swiotlb_init(int verbose, bool early)
enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;
unsigned int repeat = 3;

- xen_io_tlb_nslabs = swiotlb_nr_tbl(SWIOTLB_LO);
+ xen_io_tlb_nslabs[SWIOTLB_LO] = swiotlb_nr_tbl(SWIOTLB_LO);
retry:
- bytes = xen_set_nslabs(xen_io_tlb_nslabs);
- order = get_order(xen_io_tlb_nslabs << IO_TLB_SHIFT);
+ bytes = xen_set_nslabs(xen_io_tlb_nslabs[SWIOTLB_LO]);
+ order = get_order(xen_io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT);

/*
* IO TLB memory already allocated. Just use it.
*/
if (io_tlb_start[SWIOTLB_LO] != 0) {
- xen_io_tlb_start = phys_to_virt(io_tlb_start[SWIOTLB_LO]);
+ xen_io_tlb_start[SWIOTLB_LO] = phys_to_virt(io_tlb_start[SWIOTLB_LO]);
goto end;
}

@@ -201,76 +204,78 @@ int __ref xen_swiotlb_init(int verbose, bool early)
* Get IO TLB memory from any location.
*/
if (early) {
- xen_io_tlb_start = memblock_alloc(PAGE_ALIGN(bytes),
+ xen_io_tlb_start[SWIOTLB_LO] = memblock_alloc(PAGE_ALIGN(bytes),
PAGE_SIZE);
- if (!xen_io_tlb_start)
+ if (!xen_io_tlb_start[SWIOTLB_LO])
panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
__func__, PAGE_ALIGN(bytes), PAGE_SIZE);
} else {
#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) {
- xen_io_tlb_start = (void *)xen_get_swiotlb_free_pages(order);
- if (xen_io_tlb_start)
+ xen_io_tlb_start[SWIOTLB_LO] = (void *)xen_get_swiotlb_free_pages(order);
+ if (xen_io_tlb_start[SWIOTLB_LO])
break;
order--;
}
if (order != get_order(bytes)) {
pr_warn("Warning: only able to allocate %ld MB for software IO TLB\n",
(PAGE_SIZE << order) >> 20);
- xen_io_tlb_nslabs = SLABS_PER_PAGE << order;
- bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
+ xen_io_tlb_nslabs[SWIOTLB_LO] = SLABS_PER_PAGE << order;
+ bytes = xen_io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT;
}
}
- if (!xen_io_tlb_start) {
+ if (!xen_io_tlb_start[SWIOTLB_LO]) {
m_ret = XEN_SWIOTLB_ENOMEM;
goto error;
}
/*
* And replace that memory with pages under 4GB.
*/
- rc = xen_swiotlb_fixup(xen_io_tlb_start,
+ rc = xen_swiotlb_fixup(xen_io_tlb_start[SWIOTLB_LO],
bytes,
- xen_io_tlb_nslabs);
+ xen_io_tlb_nslabs[SWIOTLB_LO]);
if (rc) {
if (early)
- memblock_free(__pa(xen_io_tlb_start),
+ memblock_free(__pa(xen_io_tlb_start[SWIOTLB_LO]),
PAGE_ALIGN(bytes));
else {
- free_pages((unsigned long)xen_io_tlb_start, order);
- xen_io_tlb_start = NULL;
+ free_pages((unsigned long)xen_io_tlb_start[SWIOTLB_LO], order);
+ xen_io_tlb_start[SWIOTLB_LO] = NULL;
}
m_ret = XEN_SWIOTLB_EFIXUP;
goto error;
}
if (early) {
- if (swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs,
+ if (swiotlb_init_with_tbl(xen_io_tlb_start[SWIOTLB_LO],
+ xen_io_tlb_nslabs[SWIOTLB_LO],
SWIOTLB_LO, verbose))
panic("Cannot allocate SWIOTLB buffer");
rc = 0;
} else
- rc = swiotlb_late_init_with_tbl(xen_io_tlb_start,
- xen_io_tlb_nslabs, SWIOTLB_LO);
+ rc = swiotlb_late_init_with_tbl(xen_io_tlb_start[SWIOTLB_LO],
+ xen_io_tlb_nslabs[SWIOTLB_LO],
+ SWIOTLB_LO);

end:
- xen_io_tlb_end = xen_io_tlb_start + bytes;
+ xen_io_tlb_end[SWIOTLB_LO] = xen_io_tlb_start[SWIOTLB_LO] + bytes;
if (!rc)
swiotlb_set_max_segment(PAGE_SIZE, SWIOTLB_LO);

return rc;
error:
if (repeat--) {
- xen_io_tlb_nslabs = max(1024UL, /* Min is 2MB */
- (xen_io_tlb_nslabs >> 1));
+ xen_io_tlb_nslabs[SWIOTLB_LO] = max(1024UL, /* Min is 2MB */
+ (xen_io_tlb_nslabs[SWIOTLB_LO] >> 1));
pr_info("Lowering to %luMB\n",
- (xen_io_tlb_nslabs << IO_TLB_SHIFT) >> 20);
+ (xen_io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT) >> 20);
goto retry;
}
pr_err("%s (rc:%d)\n", xen_swiotlb_error(m_ret), rc);
if (early)
panic("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);
else
- free_pages((unsigned long)xen_io_tlb_start, order);
+ free_pages((unsigned long)xen_io_tlb_start[SWIOTLB_LO], order);
return rc;
}

@@ -561,7 +566,7 @@ xen_swiotlb_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
static int
xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
{
- return xen_virt_to_bus(hwdev, xen_io_tlb_end - 1) <= mask;
+ return xen_virt_to_bus(hwdev, xen_io_tlb_end[SWIOTLB_LO] - 1) <= mask;
}

const struct dma_map_ops xen_swiotlb_dma_ops = {
--
2.17.1